[feat](trx-rs): make spectrum affordable over a slow link

Spectrum dominates the server↔client connection, and all three things that
govern its cost were working against a poor link.

**It was polled, one round trip per frame.** The client asked for a frame every
50 ms on a dedicated connection and waited for the reply, so the frame rate was
capped at 1/RTT — on a 200 ms link, five frames a second no matter what was
configured.  Add SubscribeSpectrum alongside the existing SubscribeMeter: the
server pushes frames from a per-rig broadcast that rig_task fills only while
somebody is subscribed.  A server too old to know the command answers with an
error and leaves the connection usable, so the client falls back to polling on
the same connection without reconnecting.

**Bins were JSON floats.** 1024 bins spelled out as decimal text is around
10 KB a frame, ~200 KB/s at full rate — while the very next hop, client to
browser, already sends the same information as base64 i8 in about 1.4 KB.  Bins
now travel base64-encoded whole dBFS, the resolution the display draws at
anyway.  Decoding still accepts the old array form.

**Nothing was tunable.** [sdr].spectrum_fft_size and [sdr].spectrum_interval_ms
replace the compile-time FFT size and cadence; [[remotes]].spectrum_interval_ms
lets the client ask for less.  512 bins at 5 frames/s is roughly 3.5 KB/s
against roughly 200 KB/s before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SyX26FCpMQxiBoC7r5K1A7
Signed-off-by: Stan Grams <sjg@haxx.space>

CLAUDE.md

@@ -24,6 +24,12 @@ cargo test -p trx-core
 ./target/release/trx-server --print-config > trx-server.toml
 ./target/release/trx-client --print-config > trx-client.toml
 
+# Validate a config without starting anything (reports every problem)
+./target/release/trx-server --check-config --config trx-rs.toml
+
+# Regenerate trx-rs.toml.example after changing a config struct
+cargo run -p trx-config --example generate_example
+
 # Run server
 ./target/release/trx-server --config trx-server.toml
 # or via CLI args:
@@ -41,7 +47,8 @@ This is a Cargo workspace. All crates live under `src/`:
 src/
   trx-core/           # Core types, traits, state machine, controller (~3,500 LOC)
   trx-protocol/       # Client↔server protocol DTOs, auth, codec, mapping (~1,100 LOC)
-  trx-app/            # Shared application helpers (config paths, logging init)
+  trx-app/            # Shared application helpers (logging init, name normalization)
+  trx-config/         # Client + server config structs, loader, validators (~2,500 LOC)
   trx-reporting/      # PSKReporter UDP uplink + APRS-IS TCP uplink (~1,150 LOC)
   trx-server/         # Server binary: rig_task, audio pipeline, listener (~3,700 LOC)
     trx-backend/      # Backend abstraction trait + factory + dummy

Cargo.lock

@@ -2412,6 +2412,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_ignored"
+version = "0.1.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "115dffd5f3853e06e746965a20dcbae6ee747ae30b543d91b0e089668bb07798"
+dependencies = [
+ "serde",
+ "serde_core",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.149"
@@ -3031,10 +3041,6 @@ dependencies = [
 name = "trx-app"
 version = "0.1.0"
 dependencies = [
- "dirs",
- "serde",
- "thiserror 2.0.18",
- "toml",
  "tracing",
  "tracing-subscriber",
 ]
@@ -3115,6 +3121,7 @@ dependencies = [
  "toml",
  "tracing",
  "trx-app",
+ "trx-config",
  "trx-core",
  "trx-frontend",
  "trx-frontend-http",
@@ -3124,6 +3131,23 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "trx-config"
+version = "0.1.0"
+dependencies = [
+ "dirs",
+ "serde",
+ "serde_ignored",
+ "tempfile",
+ "thiserror 2.0.18",
+ "toml",
+ "toml_edit 0.22.27",
+ "tracing",
+ "trx-core",
+ "trx-decode-log",
+ "trx-reporting",
+]
+
 [[package]]
 name = "trx-configurator"
 version = "0.1.0"
@@ -3132,13 +3156,16 @@ dependencies = [
  "dialoguer",
  "tempfile",
  "tokio-serial",
+ "toml",
  "toml_edit 0.22.27",
+ "trx-config",
 ]
 
 [[package]]
 name = "trx-core"
 version = "0.1.0"
 dependencies = [
+ "base64",
  "flate2",
  "reqwest",
  "serde",
@@ -3294,12 +3321,14 @@ dependencies = [
  "trx-app",
  "trx-aprs",
  "trx-backend",
+ "trx-config",
  "trx-core",
  "trx-cw",
  "trx-decode-log",
  "trx-ftx",
  "trx-protocol",
  "trx-reporting",
+ "trx-sstv",
  "trx-vdes",
  "trx-wefax",
  "trx-wspr",
@@ -3307,6 +3336,16 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "trx-sstv"
+version = "0.1.0"
+dependencies = [
+ "base64",
+ "png",
+ "tracing",
+ "trx-core",
+]
+
 [[package]]
 name = "trx-vdes"
 version = "0.1.0"

Cargo.toml

@@ -12,11 +12,13 @@ members = [
     "src/decoders/trx-ftx",
     "src/decoders/trx-rds",
     "src/decoders/trx-vdes",
+    "src/decoders/trx-sstv",
     "src/decoders/trx-wefax",
     "src/decoders/trx-wspr",
     "src/trx-core",
     "src/trx-protocol",
     "src/trx-app",
+    "src/trx-config",
     "src/trx-reporting",
     "src/trx-server",
     "src/trx-server/trx-backend",

README.md

@@ -93,13 +93,17 @@ The wizard walks you through rig selection, serial port detection, audio
 settings, and frontend options, then writes `trx-server.toml` and
 `trx-client.toml`.
 
-Alternatively, generate example configs and edit them by hand:
+Alternatively, copy `trx-rs.toml.example` — a commented example covering every
+setting — and edit it by hand:
 
 ```bash
-./target/release/trx-server --print-config > trx-server.toml
-./target/release/trx-client --print-config > trx-client.toml
+cp trx-rs.toml.example trx-rs.toml
+./target/release/trx-server --check-config --config trx-rs.toml
 ```
 
+`--check-config` reports everything wrong with a config without starting
+anything. `--print-config` prints the same settings without comments.
+
 ### 4. Run
 
 ```bash
@@ -107,6 +111,9 @@ Alternatively, generate example configs and edit them by hand:
 ./target/release/trx-client --config trx-client.toml
 ```
 
+A single `trx-rs.toml` can configure both: the server reads its `[trx-server]`
+section and the client reads `[trx-client]`.
+
 Open the configured HTTP frontend address in a browser (default `http://localhost:8080`).
 
 ## How It Works

docs/Spectrum-Controls-Rework.md

@@ -0,0 +1,116 @@
+# Spectrum Controls — Visual Rework
+
+The strip between the spectrum and the radio controls (`#spectrum-controls`)
+holds eight controls in two groups. This proposes how it should *look*.
+
+Every control stays, in its current order, with its current name and its
+current behaviour. Nothing here changes what a button does, what commits when,
+or what is stored. It is a styling and layout change.
+
+*Status: implemented. Kept as the record of what was changed and why.*
+
+---
+
+## What it looks like now
+
+```
+Bandwidth [ 12 ] kHz  [Set] [Auto BW] [Sweet-spot]            Peak Hold [2 s] Floor [-115] dB Range [90] dB [Auto] Contrast [——●——] 1.0
+```
+
+Four problems, all of them visual:
+
+**1. Four different control heights on one line.** The bare number inputs, the
+buttons, the `select` and the range slider are each sized by their own rule, so
+nothing shares a baseline and the row reads as a pile rather than a strip.
+
+**2. Units are loose text.** `kHz`, `dB`, `dB` and the contrast value `1.0` are
+text nodes sitting outside the control they belong to, separated from it by a
+gap the same size as the gap between unrelated controls. The eye has to work
+out which number owns which unit.
+
+**3. A quarter of the strip is a hole.** `justify-content: space-between` puts
+about 250 px of nothing in the middle at 1600 px, and the two groups read as
+two unrelated things because the only thing between them is emptiness.
+
+**4. The groups stagger between 1100 and 1400 px.** The bandwidth group wraps
+to two lines while the level group stays on one, so the level group floats at a
+height of its own, aligned with neither line of the group beside it. This is
+the worst of it, and it happens at a common window width.
+
+Two smaller things: 24 px controls are below any touch-target guideline, and
+the contrast readout has no fixed width, so the row twitches as the value
+changes between `1.0` and `0.9`.
+
+## Proposed
+
+**One control height, units inside their field, and a rule where the clusters
+meet.**
+
+- **A field is one box.** Label, value and unit share a single bordered box —
+  `Bandwidth │ 12.0 │ kHz` — so a number and its unit can never be read apart.
+  Fields, buttons, the peak-hold select and the contrast slider are all 1.7 rem
+  tall, on 44 px targets under a coarse pointer.
+- **A rule, not a hole.** The two clusters are separated by a thin vertical
+  rule with normal spacing either side. The slack goes to a flexible spacer, so
+  the strip is left-aligned rather than pushed apart.
+- **A cluster never splits.** Each cluster is `nowrap`; the container wraps. If
+  a cluster does not fit on the line it drops whole to the next one,
+  left-aligned with the one above. No staggering, at any width.
+- **Rules fall away at line starts.** A cluster that begins a line has no rule
+  hanging off its left edge.
+- **The contrast readout gets a fixed, tabular slot**, so the row is still.
+
+Below the existing mobile breakpoint the strip already stacks; the same field
+component applies there, which is most of what makes it look deliberate.
+
+## What this does not change
+
+`Set` stays. `Auto BW` and `Auto` keep their names, even though they mean
+different things — that is a naming question, not a styling one. Sweet-spot
+stays where it is and keeps its behaviour. Nothing gains or loses persistence.
+Nothing moves into a popover, and no control is hidden behind a click.
+
+Those are all worth arguing about separately; a note of them is at the end of
+this file so the arguments are not lost.
+
+## Implementation
+
+One pass, no behaviour touched:
+
+1. `.spectrum-field` and `.spectrum-btn` in `style.css`, replacing the six
+   per-id rules (`#spectrum-bw-input`, `#spectrum-floor-input`,
+   `#spectrum-range-input`, `#spectrum-bw-label`, `#spectrum-floor-label`,
+   `#spectrum-range-label`) that currently repeat the same declarations.
+2. Markup in `index.html`: the loose `kHz` / `dB` text nodes move inside their
+   label, which keeps every id and every event handler exactly where it is.
+3. `#spectrum-controls` becomes a wrapping flex row with a spacer;
+   `#spectrum-bw-row` and `#spectrum-level-row` become `nowrap` clusters with a
+   left rule.
+4. The mobile block in the media query drops the rules it no longer needs.
+
+`app.ts` is not touched. Every id survives, so the existing handlers, the
+`spectrum-layout.mjs` geometry test and the broadcast-layout highlight all keep
+working.
+
+### Tests
+
+Extend `spectrum-layout.mjs`, which already measures this area:
+
+- Every control in the strip shares one height, at 1600, 1200 and 900 px.
+- No two clusters sit at different vertical offsets on the same line — the
+  staggering bug, asserted directly.
+- The strip never overflows its container and never overlaps the hint line.
+
+---
+
+## Noted for later, not proposed here
+
+Behavioural observations from reading the code, kept so they are not lost:
+
+- `Auto BW` (filter) and `Auto` (display scaling) are both called Auto, 600 px
+  apart.
+- `Floor`, `Range` and `Contrast` are not persisted; `Peak Hold` is.
+- `Auto` and `Auto BW` are one-shot: no state, nothing to turn off.
+- `Sweet-spot` retunes the SDR and waits up to 1.4 s per candidate centre, with
+  no busy indication.
+- Contrast resets on a double-click that nothing advertises.

docs/User-Manual.md

@@ -17,30 +17,61 @@ frontends.
 
 ## Configuration
 
-Both `trx-server` and `trx-client` use TOML configuration files. Use
-`--print-config` to generate a fully commented example.
+Both `trx-server` and `trx-client` read TOML. The server takes its settings
+from the `[trx-server]` section and the client from `[trx-client]`, so one
+`trx-rs.toml` can configure both — or each may live in its own file with the
+section header left off.
+
+`trx-rs.toml.example` in the repository root is a complete, commented example
+generated from the config definitions themselves. `--print-config` prints the
+same settings without the comments.
 
 ### File Locations
 
-**trx-server** lookup order:
-1. `--config <FILE>`
-2. `./trx-server.toml`
-3. `~/.trx-server.toml`
-4. `~/.config/trx-rs/server.toml`
-5. `/etc/trx-rs/server.toml`
+Both binaries use the same lookup order:
 
-**trx-client** lookup order:
 1. `--config <FILE>`
-2. `./trx-client.toml`
-3. `~/.config/trx-rs/client.toml`
-4. `/etc/trx-rs/client.toml`
+2. `./trx-rs.toml`
+3. `~/.config/trx-rs/trx-rs.toml`
+4. `/etc/trx-rs/trx-rs.toml`
 
 CLI arguments override config file values.
 
-### Environment Variables
+### Checking a Config
 
-- `TRX_PLUGIN_DIRS`: additional plugin directories (path-separated), used by
-  both server and client.
+`--check-config` loads the file, reports every problem it finds — unknown keys,
+invalid values, listeners fighting over a port — and exits without starting
+anything:
+
+```bash
+trx-server --check-config --config trx-rs.toml
+trx-client --check-config --config trx-rs.toml
+```
+
+Unknown keys are warnings by default, so a config written for a newer version
+still runs on an older binary. `--strict-config` makes them fatal.
+
+`trx-configurator --check <FILE>` runs the same checks.
+
+### Environment Variables and Secrets
+
+Any string in the config may reference an environment variable as `${VAR}`;
+an unset variable is an error rather than an empty value.
+
+Credentials can be kept out of the config entirely by pointing at a file
+instead. Every secret has a `*_file` sibling — set one or the other, never
+both:
+
+| Inline key | File key | Contents |
+|------------|----------|----------|
+| `[listen.auth].tokens` | `tokens_file` | one token per line |
+| `[[remotes]].auth.token` | `token_file` | the token |
+| `[frontends.http.auth].rx_passphrase` | `rx_passphrase_file` | the passphrase |
+| `[frontends.http.auth].control_passphrase` | `control_passphrase_file` | the passphrase |
+| `[frontends.http_json.auth].tokens` | `tokens_file` | one token per line |
+
+Blank lines and `#` comments are ignored in the list files. A config that holds
+credentials inline and is readable by group or others is flagged at startup.
 
 ### Server Options
 
@@ -96,6 +127,7 @@ CLI arguments override config file values.
 | Field | Type | Default | Description |
 |-------|------|---------|-------------|
 | `tokens` | string[] | `[]` | Allowed auth tokens (empty = no auth) |
+| `tokens_file` | string | — | Read tokens from this file, one per line |
 
 #### `[audio]`
 
@@ -121,6 +153,13 @@ When audio is enabled, at least one of `rx_enabled` or `tx_enabled` must be true
 | `sample_rate` | u32 | `1920000` | IQ capture rate in Hz |
 | `bandwidth` | u32 | `1500000` | Hardware IF filter bandwidth in Hz |
 | `center_offset_hz` | i64 | `100000` | Offset from dial to avoid DC spur |
+| `spectrum_fft_size` | usize | `1024` | Spectrum FFT bins; power of two, 128–8192 |
+| `spectrum_interval_ms` | u64 | `50` | How often a spectrum frame is pushed to subscribed clients |
+
+Spectrum is the largest thing on the client connection. On a slow or
+high-latency link, halving `spectrum_fft_size` halves the bytes per frame (at
+half the frequency resolution) and raising `spectrum_interval_ms` sends fewer of
+them; see [Spectrum over a slow link](#spectrum-over-a-slow-link).
 
 #### `[sdr.gain]`
 
@@ -197,6 +236,29 @@ Notes:
 Files are appended in JSON Lines format. Supported date tokens: `%YYYY%`,
 `%MM%`, `%DD%` (UTC).
 
+#### `[decoders]`
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `enabled` | string[] | all decoders | Decoders to run for this rig |
+| `output_dir` | string | `"$XDG_CACHE_HOME/trx-rs"` | Base directory for decoders that write images |
+
+Valid decoder names: `aprs`, `aprs_hf`, `ais`, `cw`, `ft2`, `ft4`, `ft8`,
+`lrpt`, `sstv`, `vdes`, `wefax`, `wspr` — the same names `[[sdr.channels]]`
+uses. An unrecognised name is a config error.
+
+Every decoder runs by default, which costs real CPU on a small machine. On a
+station that only works digital modes, listing just what you use is worth it:
+
+```toml
+[decoders]
+enabled = ["ft8", "ft4", "wspr"]
+```
+
+`sstv`, `wefax` and `lrpt` write images into a subdirectory of `output_dir`
+named after the decoder. `ais` and `vdes` additionally require an SDR channel
+configured to feed them.
+
 #### Multi-Rig Configuration
 
 Use `[[rigs]]` arrays instead of the flat `[rig]` section for multi-rig setups:
@@ -240,12 +302,32 @@ Rigs without an explicit `id` get auto-generated IDs like `ft817_0`, `soapysdr_1
 |-------|------|---------|-------------|
 | `url` | string | — | Server address (e.g. `localhost:4530`) |
 | `poll_interval_ms` | u64 | `750` | State poll interval |
+| `spectrum_interval_ms` | u64 | `50` | Spectrum frame interval; also settable per `[[remotes]]` entry |
 
 #### `[remote.auth]`
 
 | Field | Type | Default | Description |
 |-------|------|---------|-------------|
 | `token` | string | — | Auth token (must not be empty if set) |
+| `token_file` | string | — | Read the token from this file instead |
+
+#### `[[remotes]]`
+
+Preferred over the single `[remote]` section: one entry per rig, each mapping a
+short name to a server and an optional server-side rig id.
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `name` | string | — | Short name used everywhere in the client |
+| `url` | string | — | Server address (`host:port`) |
+| `rig_id` | string | — | Rig id on a multi-rig server |
+| `auth.token` | string | — | Auth token |
+| `auth.token_file` | string | — | Read the token from this file instead |
+| `poll_interval_ms` | u64 | `750` | State poll interval |
+
+The `name` is the key used by `default_rig_name`, `rigctl.rig_ports`,
+`audio.rig_urls`, `audio.rig_ports` and `decode_history_retention_min_by_rig`.
+A name in any of those maps that no remote answers to is a config error.
 
 #### `[frontends.http]`
 
@@ -254,6 +336,31 @@ Rigs without an explicit `id` get auto-generated IDs like `ft817_0`, `soapysdr_1
 | `enabled` | bool | `true` | Enable web UI |
 | `listen` | ip | `127.0.0.1` | Bind address |
 | `port` | u16 | `8080` | Bind port |
+| `default_rig_name` | string | — | Remote selected on startup |
+| `initial_map_zoom` | u8 | `10` | Starting zoom for the APRS map |
+| `show_sdr_gain_control` | bool | `true` | Expose the RF gain control |
+| `bandplan_enabled` | bool | `true` | Show the bandplan strip |
+| `bandplan_region` | string | `"iaru_r1"` | `iaru_r1`, `iaru_r2`, or `iaru_r3` |
+| `decode_history_retention_min` | u64 | `1440` | Decode history retention |
+| `decode_history_retention_min_by_rig` | table | `{}` | Per-remote retention override |
+| `spectrum_coverage_margin_hz` | u32 | `50000` | Centre-retune guard margin |
+| `spectrum_usable_span_ratio` | f32 | `0.92` | Usable fraction of the sampled span |
+
+#### `[frontends.http.auth]`
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `enabled` | bool | `false` | Require a passphrase |
+| `rx_passphrase` | string | — | Passphrase granting receive-only access |
+| `rx_passphrase_file` | string | — | Read it from this file instead |
+| `control_passphrase` | string | — | Passphrase granting full control |
+| `control_passphrase_file` | string | — | Read it from this file instead |
+| `tx_access_control_enabled` | bool | `true` | Hide TX from unauthenticated users |
+| `session_ttl_min` | u64 | `480` | Session lifetime |
+| `cookie_secure` | bool | `false` | Set Secure on the session cookie (needs HTTPS) |
+| `cookie_same_site` | string | `"Lax"` | `Strict`, `Lax`, or `None` |
+
+With `enabled = true`, at least one passphrase must be set.
 
 #### `[frontends.rigctl]`
 
@@ -261,7 +368,11 @@ Rigs without an explicit `id` get auto-generated IDs like `ft817_0`, `soapysdr_1
 |-------|------|---------|-------------|
 | `enabled` | bool | `false` | Enable Hamlib rigctl |
 | `listen` | ip | `127.0.0.1` | Bind address |
-| `port` | u16 | `4532` | Bind port |
+| `rig_ports` | table | `{}` | Remote name → local port; one listener each |
+
+One listener is started per `rig_ports` entry, each routing to its rig, so
+`rig_ports` must name at least one remote when the frontend is enabled. The
+older single `port` key and `--rigctl-port` are ignored.
 
 #### `[frontends.http_json]`
 
@@ -271,13 +382,17 @@ Rigs without an explicit `id` get auto-generated IDs like `ft817_0`, `soapysdr_1
 | `listen` | ip | `127.0.0.1` | Bind address |
 | `port` | u16 | `0` | Bind port (0 = ephemeral) |
 | `auth.tokens` | string[] | `[]` | Allowed auth tokens |
+| `auth.tokens_file` | string | — | Read tokens from this file, one per line |
 
 #### `[frontends.audio]`
 
 | Field | Type | Default | Description |
 |-------|------|---------|-------------|
 | `enabled` | bool | `true` | Enable audio client |
-| `server_port` | u16 | `4531` | Server audio port |
+| `server_url` | string | — | Audio endpoint for every remote |
+| `rig_urls` | table | `{}` | Remote name → audio URL (wins over `server_url`) |
+| `server_port` | u16 | `4531` | Fallback port when no URL is configured |
+| `rig_ports` | table | `{}` | Remote name → port; superseded by `rig_urls` |
 | `bridge.enabled` | bool | `false` | Enable local CPAL audio bridge |
 | `bridge.rx_output_device` | string | — | Local playback device |
 | `bridge.tx_input_device` | string | — | Local capture device |
@@ -287,16 +402,88 @@ Rigs without an explicit `id` get auto-generated IDs like `ft817_0`, `soapysdr_1
 The bridge is intended for WSJT-X integration via virtual audio devices (ALSA
 loopback on Linux, BlackHole on macOS).
 
+### Spectrum over a slow link
+
+Spectrum dominates the server↔client connection: everything else is a few
+hundred bytes, a frame is a few kilobytes. Three things govern what it costs.
+
+**Frames are pushed, not polled.** The client subscribes and the server sends
+frames at `[sdr].spectrum_interval_ms`. Polling cost a round trip per frame, so
+the rate was capped at 1/RTT — on a 200 ms link you could not exceed 5 frames a
+second however often the client asked. Clients fall back to polling
+automatically against a server too old to stream.
+
+**Bins travel as whole dBFS.** They are base64-encoded `i8` on the wire, about
+an eighth of the JSON array of floats they used to be, at the resolution the
+display draws anyway.
+
+**Both ends have a rate, and the slower one wins.** The server pushes no faster
+than `[sdr].spectrum_interval_ms`; the client asks for no more than
+`[[remotes]].spectrum_interval_ms`.
+
+For a link that struggles, start here:
+
+```toml
+[trx-server.sdr]
+spectrum_fft_size = 512      # half the bins, half the bytes
+spectrum_interval_ms = 200   # 5 frames/s instead of 20
+
+[[trx-client.remotes]]
+name = "remote-site"
+url = "radio.example.com:4530"
+spectrum_interval_ms = 200
+```
+
+That is roughly 0.7 KB per frame at 5 frames/s — about 3.5 KB/s, against
+roughly 200 KB/s for 1024 float bins at 20 frames/s.
+
 ### CLI Override Summary
 
 **trx-server:**
-`--config`, `--print-config`, `--rig`, `--access`, `--callsign`, `--listen`,
-`--port`. SDR options are file-only.
+`--config`, `--print-config`, `--check-config`, `--strict-config`, `--rig`,
+`--access`, `--callsign`, `--listen`, `--port`. SDR options are file-only.
 
 **trx-client:**
-`--config`, `--print-config`, `--url`, `--token`, `--poll-interval`,
-`--frontend`, `--http-listen`, `--http-port`, `--rigctl-listen`,
-`--rigctl-port`, `--http-json-listen`, `--http-json-port`, `--callsign`.
+`--config`, `--print-config`, `--check-config`, `--strict-config`, `--url`,
+`--token`, `--poll-interval`, `--rig-id`, `--frontend`, `--http-listen`,
+`--http-port`, `--rigctl-listen`, `--http-json-listen`, `--http-json-port`,
+`--callsign`.
+
+`--listen` on the server overrides the bind address of both the control
+listener and every rig's audio listener.
+
+---
+
+## Tune Links
+
+Every page of the web UI carries what the radio is doing in its address, so the
+URL in the address bar is always a link someone else can open:
+
+```
+http://receiver.example:8080/?rig=sdr&f=14074000&mode=USB&bw=3000
+```
+
+| Parameter | Meaning |
+|-----------|---------|
+| `f` | Frequency. Hz by default; `7074k` and `14.074M` also work. |
+| `mode` | Demodulation mode, e.g. `USB`, `CW`, `WFM`. |
+| `bw` | Filter bandwidth in Hz. Ignored by rigs without filter control. |
+| `rig` | Rig to select first, by id, on a multi-rig client. |
+
+Opening such a link selects the rig, sets the mode, tunes, and applies the
+bandwidth, in that order — a mode change carries its own default bandwidth, so
+an explicit `bw` is applied last. Anything the rig cannot do (an unknown mode,
+a frequency outside its range) is reported and the rest of the link still
+applies. All four parameters are optional.
+
+The link button in the top bar copies the current link to the clipboard. The
+address bar itself is updated as you tune, using `replaceState`, so sweeping
+the dial does not fill the browser's history.
+
+Applying a link changes the radio, so it needs the `control` role; an `rx`
+session opens the page and says the link was not applied. Links describe the
+rig's own dial — while a tab is listening to a virtual channel the address is
+left as it was, rather than publishing a frequency the rig is not on.
 
 ---
 

src/decoders/trx-sstv/Cargo.toml

@@ -0,0 +1,14 @@
+# SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+[package]
+name = "trx-sstv"
+version.workspace = true
+edition = "2021"
+
+[dependencies]
+trx-core = { path = "../../trx-core" }
+base64 = "0.22"
+png = "0.17"
+tracing = "0.1"

src/decoders/trx-sstv/examples/round_trip_png.rs

@@ -0,0 +1,91 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Encode a test card, decode it back, write both as PNGs to a directory.
+//!
+//! `cargo run -p trx-sstv --example round_trip_png -- /tmp/out`
+
+use trx_sstv::encode::{encode, Frame};
+use trx_sstv::mode::mode_for_vis;
+use trx_sstv::{ImageCanvas, SstvConfig, SstvDecoder, SstvEvent};
+
+fn main() {
+    let dir = std::env::args().nth(1).unwrap_or_else(|| ".".into());
+    for vis in [44u8, 60, 12, 8, 95] {
+        let mode = mode_for_vis(vis).expect("mode in table");
+        let (w, h) = (usize::from(mode.width), usize::from(mode.height));
+        let mut rgb = vec![0u8; w * h * 3];
+        for y in 0..h {
+            for x in 0..w {
+                let at = (y * w + x) * 3;
+                let (r, g, b) = if y < h / 3 {
+                    [
+                        (255u8, 255u8, 255u8),
+                        (255, 255, 0),
+                        (0, 255, 255),
+                        (0, 255, 0),
+                        (255, 0, 255),
+                        (255, 0, 0),
+                        (0, 0, 255),
+                        (0, 0, 0),
+                    ][x * 8 / w]
+                } else if y < 2 * h / 3 {
+                    let t = (x * 255 / w) as u8;
+                    (t, 255 - t, ((y * 255) / h) as u8)
+                } else {
+                    // Diagonal stripes: a line-timing error shows up as a kink.
+                    if ((x + y) / 16) % 2 == 0 {
+                        (240, 240, 40)
+                    } else {
+                        (20, 20, 90)
+                    }
+                };
+                rgb[at] = r;
+                rgb[at + 1] = g;
+                rgb[at + 2] = b;
+            }
+        }
+        let name = mode.name.replace(' ', "-");
+        let mut sent = ImageCanvas::new(w, h);
+        for y in 0..h {
+            sent.put_row(y, &rgb[y * w * 3..(y + 1) * w * 3]);
+        }
+        std::fs::write(
+            format!("{dir}/{name}-sent.png"),
+            sent.to_png().expect("png"),
+        )
+        .expect("write");
+
+        let frame = Frame {
+            width: w,
+            height: h,
+            rgb: &rgb,
+        };
+        let mut audio = encode(mode, &frame, 48_000);
+        audio.extend(std::iter::repeat_n(0.0, 4800));
+        let mut decoder = SstvDecoder::new(48_000, SstvConfig::default());
+        let mut got = None;
+        for block in audio.chunks(1024) {
+            for event in decoder.process_samples(block) {
+                if let SstvEvent::Complete(image) = event {
+                    got = Some(image);
+                }
+            }
+        }
+        let image = got.expect("no image decoded");
+        let mut canvas = ImageCanvas::new(w, h);
+        for y in 0..h {
+            canvas.put_row(y, &image.rgb[y * w * 3..(y + 1) * w * 3]);
+        }
+        std::fs::write(
+            format!("{dir}/{name}-decoded.png"),
+            canvas.to_png().expect("png"),
+        )
+        .expect("write");
+        println!(
+            "{}: {} lines, complete={}",
+            mode.name, image.lines, image.complete
+        );
+    }
+}

src/decoders/trx-sstv/src/config.rs

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! SSTV decoder configuration.
+
+/// Settings for [`crate::decoder::SstvDecoder`].
+#[derive(Debug, Clone, Default)]
+pub struct SstvConfig {
+    /// VIS code of a mode to assume when no header is heard, so tuning in
+    /// part-way through a transmission still produces a picture. `None` means
+    /// wait for a header, which is the safe default: guessing wrong yields a
+    /// convincing image of nothing.
+    pub force_mode: Option<u8>,
+    /// Directory for saved PNGs. `None` keeps images in memory only.
+    pub output_dir: Option<String>,
+}

src/decoders/trx-sstv/src/decoder.rs

@@ -0,0 +1,659 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! The decoder: audio in, pictures out.
+//!
+//! Reception is a small state machine. It listens for a VIS header, and once
+//! one names a mode it walks the transmission a line at a time, sampling each
+//! scan at the offsets the mode's segment list gives. Every line is looked for
+//! at the time the mode says it should arrive, then nudged into place by the
+//! sync pulse actually found near it — a transmitter's clock and a receiver's
+//! sound card never agree exactly, and over two minutes of Martin M1 an
+//! uncorrected error of a few parts per million visibly shears the picture.
+//!
+//! Rows are emitted as they are decoded so a picture can be watched arriving,
+//! which is most of the appeal of the mode.
+
+use crate::config::SstvConfig;
+use crate::demod::FreqDemod;
+use crate::image::ImageCanvas;
+use crate::mode::{level_from_hz, mode_for_vis, Channel, ColorModel, SstvMode};
+use crate::vis::find_vis;
+
+/// Anything below this is the sync pulse rather than picture: black is 1500 Hz
+/// and sync is 1200 Hz, so the line sits between them.
+const SYNC_THRESHOLD_HZ: f32 = 1350.0;
+
+/// How much of the signal to keep while hunting for a header. A header is 940
+/// ms; two seconds leaves room for one to straddle several blocks of audio.
+const SEARCH_HISTORY_MS: f64 = 2000.0;
+
+/// From the start bit to the end of the stop bit: ten 30 ms cells. A header
+/// search must never retire a stretch shorter than this, or a start bit split
+/// across two blocks of audio is dismissed on half a view of it.
+const HEADER_SPAN_MS: f64 = 330.0;
+
+/// How far from its predicted position a line's sync pulse is looked for.
+const SYNC_SEARCH_MS: f64 = 12.0;
+
+/// Fraction of the observed timing error applied to the next line. Damped,
+/// because a sync pulse found in noise is worth less than the prediction.
+const SYNC_CORRECTION: f64 = 0.45;
+
+/// Consecutive lines with no sync pulse anywhere near the prediction before
+/// the transmission is taken to have ended.
+const MISSING_SYNC_LIMIT: u32 = 8;
+
+/// What the decoder has to say.
+#[derive(Debug, Clone)]
+pub enum SstvEvent {
+    /// A header was decoded and reception has begun.
+    Started {
+        vis: u8,
+        mode: &'static str,
+        width: u16,
+        height: u16,
+    },
+    /// One image row is ready, as RGB triples.
+    Row { line: u16, rgb: Vec<u8> },
+    /// Reception finished — at the bottom of the frame, or because the signal
+    /// went away. Carries the picture either way.
+    Complete(SstvImage),
+}
+
+/// A received picture.
+#[derive(Debug, Clone)]
+pub struct SstvImage {
+    pub vis: u8,
+    pub mode: &'static str,
+    pub width: u16,
+    pub height: u16,
+    /// Rows actually received, which is the height only if it ran to the end.
+    pub lines: u16,
+    /// Whether the whole frame arrived.
+    pub complete: bool,
+    /// RGB triples, `width * height * 3` bytes. Rows never received are grey.
+    pub rgb: Vec<u8>,
+    /// When reception started, in milliseconds since the epoch.
+    pub started_ms: i64,
+}
+
+impl SstvImage {
+    /// The picture as a canvas, for saving or encoding.
+    pub fn canvas(&self) -> ImageCanvas {
+        let width = usize::from(self.width);
+        let mut canvas = ImageCanvas::new(width, usize::from(self.height));
+        for (y, row) in self.rgb.chunks(width * 3).enumerate() {
+            canvas.put_row(y, row);
+        }
+        canvas
+    }
+
+    /// The picture as PNG bytes.
+    pub fn to_png(&self) -> Result<Vec<u8>, String> {
+        self.canvas().to_png()
+    }
+
+    /// The picture as a base64 PNG, for the journey to a client.
+    pub fn to_png_base64(&self) -> Result<String, String> {
+        self.canvas().to_png_base64()
+    }
+
+    /// Write the picture into `dir`, named for when and where it arrived.
+    pub fn save_png(
+        &self,
+        dir: &std::path::Path,
+        freq_hz: u64,
+    ) -> Result<std::path::PathBuf, String> {
+        self.canvas()
+            .save_png(dir, freq_hz, self.mode, &stamp(self.started_ms))
+    }
+}
+
+/// `YYYYMMDDTHHMMSSZ` for a millisecond timestamp, for file names that sort.
+fn stamp(ms: i64) -> String {
+    let secs = ms.div_euclid(1000);
+    let (days, rest) = (secs.div_euclid(86_400), secs.rem_euclid(86_400));
+    let (year, month, day) = civil_from_days(days);
+    let (hour, minute, second) = (rest / 3600, (rest % 3600) / 60, rest % 60);
+    format!("{year:04}{month:02}{day:02}T{hour:02}{minute:02}{second:02}Z")
+}
+
+/// Days since the Unix epoch to a calendar date (Howard Hinnant's algorithm).
+fn civil_from_days(days: i64) -> (i64, u32, u32) {
+    let z = days + 719_468;
+    let era = z.div_euclid(146_097);
+    let doe = z.rem_euclid(146_097);
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365;
+    let y = yoe + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let d = (doy - (153 * mp + 2) / 5 + 1) as u32;
+    let m = if mp < 10 { mp + 3 } else { mp - 9 } as u32;
+    (if m <= 2 { y + 1 } else { y }, m, d)
+}
+
+enum State {
+    /// Listening for a header.
+    Searching,
+    Receiving(Box<Reception>),
+}
+
+struct Reception {
+    mode: &'static SstvMode,
+    canvas: ImageCanvas,
+    /// Absolute sample index at which the next transmitted line begins.
+    next_line: f64,
+    /// Next image row to write.
+    row: u16,
+    started_ms: i64,
+    missing_syncs: u32,
+    /// Set until the first line has been decoded. A VIS header ends exactly
+    /// where the picture begins, so the first line is already aligned — and a
+    /// search would find the header's own 30 ms stop bit, which is at the sync
+    /// frequency and sits immediately before the picture.
+    first_line: bool,
+    /// Robot 36 sends one chroma channel per line and expects the decoder to
+    /// carry the other over from the line before.
+    last_chroma_r: Option<Vec<u8>>,
+    last_chroma_b: Option<Vec<u8>>,
+}
+
+pub struct SstvDecoder {
+    sample_rate: u32,
+    config: SstvConfig,
+    demod: FreqDemod,
+    /// Instantaneous frequency, one entry per audio sample. Delayed by the
+    /// demodulator's group delay, which is constant and so shifts the whole
+    /// stream — header and lines alike — without disturbing their spacing.
+    freqs: Vec<f32>,
+    /// Absolute index of `freqs[0]`, so positions survive the buffer being
+    /// trimmed.
+    base: u64,
+    /// Absolute index the header search has already covered.
+    searched_to: u64,
+    state: State,
+}
+
+impl SstvDecoder {
+    pub fn new(sample_rate: u32, config: SstvConfig) -> Self {
+        Self {
+            sample_rate,
+            config,
+            demod: FreqDemod::new(sample_rate),
+            freqs: Vec::new(),
+            base: 0,
+            searched_to: 0,
+            state: State::Searching,
+        }
+    }
+
+    /// Whether a picture is currently arriving.
+    pub fn is_receiving(&self) -> bool {
+        matches!(self.state, State::Receiving(_))
+    }
+
+    /// Feed a block of mono audio. Returns whatever it produced.
+    pub fn process_samples(&mut self, samples: &[f32]) -> Vec<SstvEvent> {
+        self.demod.process_into(samples, &mut self.freqs);
+        let mut events = Vec::new();
+        loop {
+            let progressed = match self.state {
+                State::Searching => self.try_start(&mut events),
+                State::Receiving(_) => self.try_line(&mut events),
+            };
+            if !progressed {
+                break;
+            }
+        }
+        self.trim();
+        events
+    }
+
+    /// Abandon a reception in progress, returning the picture so far.
+    pub fn reset(&mut self) -> Vec<SstvEvent> {
+        let mut events = Vec::new();
+        if let State::Receiving(reception) = std::mem::replace(&mut self.state, State::Searching) {
+            events.push(SstvEvent::Complete(finish(&reception)));
+        }
+        self.demod.reset();
+        self.freqs.clear();
+        self.base = 0;
+        self.searched_to = 0;
+        events
+    }
+
+    /// Look for a header, or for a bare sync pulse when the mode is forced.
+    fn try_start(&mut self, events: &mut Vec<SstvEvent>) -> bool {
+        let from = self.searched_to.saturating_sub(self.base) as usize;
+        if from >= self.freqs.len() {
+            return false;
+        }
+
+        if let Some(hit) = find_vis(&self.freqs, self.sample_rate, from) {
+            if let Some(mode) = mode_for_vis(hit.code) {
+                self.begin(mode, self.base + hit.image_start as u64, events);
+                return true;
+            }
+            // A header that parses but names a mode this decoder does not know
+            // is still a header: skip past it rather than finding it again.
+            tracing::debug!(vis = hit.code, "SSTV: unsupported mode");
+            self.searched_to = self.base + hit.image_start as u64;
+            return true;
+        }
+
+        // Tuning in mid-transmission means no header to find. With a mode
+        // named in the configuration, the first sync pulse is enough to start.
+        if let Some(mode) = self.config.force_mode.and_then(mode_for_vis) {
+            if let Some(sync) = self.find_sync(from, self.freqs.len(), mode) {
+                let line_start = (self.base + sync as u64) as f64
+                    - ms_to_samples(mode.sync_offset_ms, self.sample_rate);
+                self.begin_at(mode, line_start.max(0.0), events);
+                return true;
+            }
+        }
+
+        // Nothing yet. Rewind the cursor by a header's worth of samples before
+        // marking the buffer searched: audio arrives in blocks of a few
+        // milliseconds, so the search regularly runs over a start bit that is
+        // only half here. Advancing past it would retire the header for good
+        // on the strength of a partial view of it.
+        let unsearchable = ms_to_samples(HEADER_SPAN_MS, self.sample_rate) as u64;
+        let end = self.base + self.freqs.len() as u64;
+        self.searched_to = self.searched_to.max(end.saturating_sub(unsearchable));
+        false
+    }
+
+    fn begin(&mut self, mode: &'static SstvMode, image_start: u64, events: &mut Vec<SstvEvent>) {
+        self.begin_at(mode, image_start as f64, events);
+    }
+
+    fn begin_at(&mut self, mode: &'static SstvMode, line_start: f64, events: &mut Vec<SstvEvent>) {
+        events.push(SstvEvent::Started {
+            vis: mode.vis,
+            mode: mode.name,
+            width: mode.width,
+            height: mode.height,
+        });
+        self.state = State::Receiving(Box::new(Reception {
+            mode,
+            canvas: ImageCanvas::new(usize::from(mode.width), usize::from(mode.height)),
+            next_line: line_start,
+            row: 0,
+            started_ms: now_ms(),
+            missing_syncs: 0,
+            first_line: true,
+            last_chroma_r: None,
+            last_chroma_b: None,
+        }));
+    }
+
+    /// Decode one transmitted line, if all of it has arrived.
+    fn try_line(&mut self, events: &mut Vec<SstvEvent>) -> bool {
+        let State::Receiving(reception) = &mut self.state else {
+            return false;
+        };
+        let mode = reception.mode;
+        let line_samples = ms_to_samples(mode.line_ms, self.sample_rate);
+        let margin = ms_to_samples(SYNC_SEARCH_MS, self.sample_rate);
+
+        let start = reception.next_line;
+        // Enough for the line's own scans, and for the sync search to reach as
+        // far ahead as it looks — no further. Demanding the search margin past
+        // the end of every line would cost the last line of every picture,
+        // which is exactly where the transmission stops.
+        let sync_reach = start + ms_to_samples(mode.sync_offset_ms, self.sample_rate) + margin;
+        let end = (start + line_samples).max(sync_reach);
+        let available = (self.base + self.freqs.len() as u64) as f64;
+        if end > available {
+            return false;
+        }
+        // The line may begin before what is still buffered if the caller fed a
+        // huge block; nothing can be done about that but skip forward.
+        if start < self.base as f64 {
+            reception.next_line = self.base as f64;
+            return true;
+        }
+
+        // Line up on the sync pulse near where this line is predicted to be.
+        let expected_sync = start + ms_to_samples(mode.sync_offset_ms, self.sample_rate);
+        let from = (expected_sync - margin).max(self.base as f64) as u64;
+        let to = (expected_sync + margin) as u64;
+        let searching = !matches!(&self.state, State::Receiving(r) if r.first_line);
+        let found = if searching {
+            self.find_sync_between(from, to, mode)
+        } else {
+            None
+        };
+        let State::Receiving(reception) = &mut self.state else {
+            return false;
+        };
+        let start = match found {
+            Some(sync_at) => {
+                reception.missing_syncs = 0;
+                let error = sync_at as f64 - expected_sync;
+                reception.next_line += error * SYNC_CORRECTION;
+                reception.next_line
+            }
+            None if reception.first_line => start,
+            None => {
+                reception.missing_syncs += 1;
+                start
+            }
+        };
+
+        if reception.missing_syncs >= MISSING_SYNC_LIMIT {
+            let image = finish(reception);
+            self.state = State::Searching;
+            self.searched_to = self.base + self.freqs.len() as u64;
+            events.push(SstvEvent::Complete(image));
+            return true;
+        }
+
+        // Sample every scan of the line, then colour the rows.
+        let mut scans: Vec<(Channel, Vec<u8>)> = Vec::new();
+        for (channel, offset_ms, ms) in mode.scans() {
+            let pixels = mode.scan_pixels(channel);
+            let at = start + ms_to_samples(offset_ms, self.sample_rate);
+            let values = sample_scan(&self.freqs, self.base, at, ms, pixels, self.sample_rate);
+            scans.push((channel, values));
+        }
+
+        let State::Receiving(reception) = &mut self.state else {
+            return false;
+        };
+        let rows = compose_rows(reception, &scans);
+        for (offset, row) in rows.into_iter().enumerate() {
+            let line = reception.row + offset as u16;
+            reception.canvas.put_row(usize::from(line), &row);
+            events.push(SstvEvent::Row { line, rgb: row });
+        }
+        reception.first_line = false;
+        reception.row += mode.lines_per_transmission;
+        reception.next_line += line_samples;
+
+        if reception.row >= mode.height {
+            let image = finish(reception);
+            self.state = State::Searching;
+            self.searched_to = self.base + self.freqs.len() as u64;
+            events.push(SstvEvent::Complete(image));
+        }
+        true
+    }
+
+    /// First sync pulse of about the right length in `freqs[from..to]`,
+    /// as an index of its leading edge.
+    ///
+    /// Works on a smoothed copy of the window: a sync pulse is 1200 Hz, where
+    /// the raw per-sample estimate swings by ±95 Hz, so single samples cross
+    /// and re-cross the threshold throughout a pulse and no run is ever long
+    /// enough. Pixels are sampled from the raw signal, where averaging over
+    /// the pixel does the same job without blurring across its edges.
+    fn find_sync(&self, from: usize, to: usize, mode: &SstvMode) -> Option<usize> {
+        let want = sync_ms(mode);
+        let min_run = (ms_to_samples(want, self.sample_rate) * 0.6) as usize;
+        // A sync pulse ends. Silence and a dead carrier demodulate to near
+        // zero, which is below the threshold too, and without an upper bound a
+        // decoder left running on an empty channel finds sync everywhere and
+        // fills the picture with noise it invented.
+        let max_run = (ms_to_samples(want, self.sample_rate) * 3.0) as usize;
+        let to = to.min(self.freqs.len());
+        if from >= to {
+            return None;
+        }
+        // Reach past the end of the search window by a whole pulse: a sync
+        // starting at the last moment the window allows still has to be
+        // measurable to its full length, or it is rejected for being short and
+        // the line it belongs to goes unaligned.
+        let pad = ms_to_samples(want + 2.0, self.sample_rate) as usize;
+        let window_from = from.saturating_sub(pad);
+        let window_to = (to + pad).min(self.freqs.len());
+        let smoothed = crate::demod::smooth(
+            &self.freqs[window_from..window_to],
+            ms_to_samples(1.0, self.sample_rate) as usize,
+        );
+
+        let mut i = from - window_from;
+        let scan_to = to - window_from;
+        while i < scan_to {
+            if smoothed[i] >= SYNC_THRESHOLD_HZ {
+                i += 1;
+                continue;
+            }
+            let mut run = 0;
+            while i + run < smoothed.len() && smoothed[i + run] < SYNC_THRESHOLD_HZ {
+                run += 1;
+            }
+            if run >= min_run && run <= max_run {
+                return Some(window_from + i);
+            }
+            i += run.max(1);
+        }
+        None
+    }
+
+    /// As [`Self::find_sync`], over an absolute index range.
+    fn find_sync_between(&self, from: u64, to: u64, mode: &SstvMode) -> Option<u64> {
+        let from = from.saturating_sub(self.base) as usize;
+        let to = to.saturating_sub(self.base) as usize;
+        if from >= self.freqs.len() {
+            return None;
+        }
+        self.find_sync(from, to, mode)
+            .map(|at| self.base + at as u64)
+    }
+
+    /// Drop what is behind the decoder, so a long reception does not grow the
+    /// buffer without bound.
+    fn trim(&mut self) {
+        let keep_from = match &self.state {
+            State::Searching => {
+                let history = ms_to_samples(SEARCH_HISTORY_MS, self.sample_rate) as u64;
+                (self.base + self.freqs.len() as u64).saturating_sub(history)
+            }
+            State::Receiving(reception) => {
+                let margin = ms_to_samples(SYNC_SEARCH_MS * 2.0, self.sample_rate) as u64;
+                (reception.next_line as u64).saturating_sub(margin)
+            }
+        };
+        if keep_from <= self.base {
+            return;
+        }
+        let drop = (keep_from - self.base) as usize;
+        if drop >= self.freqs.len() {
+            self.freqs.clear();
+        } else {
+            self.freqs.drain(..drop);
+        }
+        self.base = keep_from;
+        self.searched_to = self.searched_to.max(self.base);
+    }
+}
+
+/// The sync pulse length of a mode, read out of its own segment list.
+fn sync_ms(mode: &SstvMode) -> f64 {
+    mode.segments
+        .iter()
+        .find_map(|segment| match segment {
+            crate::mode::Segment::Sync(ms) => Some(*ms),
+            _ => None,
+        })
+        .unwrap_or(9.0)
+}
+
+/// Milliseconds since the epoch, for stamping a picture with when it arrived.
+fn now_ms() -> i64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_millis() as i64
+}
+
+fn ms_to_samples(ms: f64, sample_rate: u32) -> f64 {
+    ms / 1000.0 * f64::from(sample_rate)
+}
+
+/// Average the frequency across each pixel's window and turn it into a level.
+///
+/// The middle 60% of the window is used: a pixel's edges carry the
+/// demodulator's transition from the pixel before, and including them smears
+/// every edge in the picture.
+fn sample_scan(
+    freqs: &[f32],
+    base: u64,
+    start: f64,
+    ms: f64,
+    pixels: usize,
+    sample_rate: u32,
+) -> Vec<u8> {
+    let mut out = Vec::with_capacity(pixels);
+    let width = ms_to_samples(ms, sample_rate) / pixels as f64;
+    for x in 0..pixels {
+        let pixel_start = start + width * x as f64;
+        let from = (pixel_start + width * 0.2 - base as f64).max(0.0) as usize;
+        let to = ((pixel_start + width * 0.8 - base as f64).max(0.0) as usize).min(freqs.len());
+        // A pixel narrower than a sample still has to produce one.
+        let (from, to) = if to > from {
+            (from, to)
+        } else {
+            let at = (pixel_start - base as f64).max(0.0) as usize;
+            (
+                at.min(freqs.len().saturating_sub(1)),
+                (at + 1).min(freqs.len()),
+            )
+        };
+        if to <= from {
+            out.push(0);
+            continue;
+        }
+        let window = &freqs[from..to];
+        let mean = window.iter().sum::<f32>() / window.len() as f32;
+        out.push(level_from_hz(mean));
+    }
+    out
+}
+
+/// Turn one line's scans into image rows.
+fn compose_rows(reception: &mut Reception, scans: &[(Channel, Vec<u8>)]) -> Vec<Vec<u8>> {
+    let mode = reception.mode;
+    let width = usize::from(mode.width);
+    let find = |channel: Channel| scans.iter().find(|(c, _)| *c == channel).map(|(_, v)| v);
+
+    match mode.color {
+        ColorModel::Rgb => {
+            let red = find(Channel::Red);
+            let green = find(Channel::Green);
+            let blue = find(Channel::Blue);
+            let mut row = vec![0u8; width * 3];
+            for x in 0..width {
+                row[x * 3] = red.and_then(|c| c.get(x).copied()).unwrap_or(0);
+                row[x * 3 + 1] = green.and_then(|c| c.get(x).copied()).unwrap_or(0);
+                row[x * 3 + 2] = blue.and_then(|c| c.get(x).copied()).unwrap_or(0);
+            }
+            vec![row]
+        }
+        ColorModel::YCrCb => {
+            let luma = find(Channel::LumaOdd).cloned().unwrap_or_default();
+            let cr = find(Channel::ChromaR).cloned().unwrap_or_default();
+            let cb = find(Channel::ChromaB).cloned().unwrap_or_default();
+            vec![ycrcb_row(&luma, &cr, &cb, width)]
+        }
+        ColorModel::YCrCbAlternating => {
+            // This line carries one chroma channel; the other is the one from
+            // the line before, which is what the mode expects a decoder to do.
+            let luma = find(Channel::LumaOdd).cloned().unwrap_or_default();
+            let chroma = find(Channel::ChromaAlternating)
+                .cloned()
+                .unwrap_or_default();
+            if reception.row.is_multiple_of(2) {
+                reception.last_chroma_r = Some(chroma);
+            } else {
+                reception.last_chroma_b = Some(chroma);
+            }
+            let neutral = vec![128u8; luma.len().max(1) / 2];
+            let cr = reception
+                .last_chroma_r
+                .clone()
+                .unwrap_or_else(|| neutral.clone());
+            let cb = reception.last_chroma_b.clone().unwrap_or(neutral);
+            vec![ycrcb_row(&luma, &cr, &cb, width)]
+        }
+        ColorModel::YCrCbPaired => {
+            let odd = find(Channel::LumaOdd).cloned().unwrap_or_default();
+            let even = find(Channel::LumaEven).cloned().unwrap_or_default();
+            let cr = find(Channel::ChromaR).cloned().unwrap_or_default();
+            let cb = find(Channel::ChromaB).cloned().unwrap_or_default();
+            vec![
+                ycrcb_row(&odd, &cr, &cb, width),
+                ycrcb_row(&even, &cr, &cb, width),
+            ]
+        }
+    }
+}
+
+/// One RGB row from luminance and chrominance, stretching the chroma scans
+/// across the width when they are narrower than it.
+fn ycrcb_row(luma: &[u8], cr: &[u8], cb: &[u8], width: usize) -> Vec<u8> {
+    let mut row = vec![0u8; width * 3];
+    let pick = |channel: &[u8], x: usize| -> f32 {
+        if channel.is_empty() {
+            return 128.0;
+        }
+        let at = x * channel.len() / width.max(1);
+        f32::from(channel[at.min(channel.len() - 1)])
+    };
+    for x in 0..width {
+        let y = if luma.is_empty() {
+            0.0
+        } else {
+            let at = x * luma.len() / width.max(1);
+            f32::from(luma[at.min(luma.len() - 1)])
+        };
+        let (r, g, b) = ycrcb_to_rgb(y, pick(cr, x), pick(cb, x));
+        row[x * 3] = r;
+        row[x * 3 + 1] = g;
+        row[x * 3 + 2] = b;
+    }
+    row
+}
+
+/// The inverse of the studio-swing conversion SSTV encoders use.
+fn ycrcb_to_rgb(y: f32, cr: f32, cb: f32) -> (u8, u8, u8) {
+    let r = 298.082 * y / 256.0 + 408.583 * cr / 256.0 - 222.921;
+    let g = 298.082 * y / 256.0 - 100.291 * cb / 256.0 - 208.120 * cr / 256.0 + 135.576;
+    let b = 298.082 * y / 256.0 + 516.412 * cb / 256.0 - 276.836;
+    (
+        r.clamp(0.0, 255.0) as u8,
+        g.clamp(0.0, 255.0) as u8,
+        b.clamp(0.0, 255.0) as u8,
+    )
+}
+
+fn finish(reception: &Reception) -> SstvImage {
+    SstvImage {
+        vis: reception.mode.vis,
+        mode: reception.mode.name,
+        width: reception.mode.width,
+        height: reception.mode.height,
+        lines: reception.canvas.filled_rows() as u16,
+        complete: reception.row >= reception.mode.height,
+        rgb: reception.canvas.rgb().to_vec(),
+        started_ms: reception.started_ms,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn file_stamps_are_utc_and_sort_in_time_order() {
+        // Known instants, checked against `date -u -r <secs>`.
+        assert_eq!(stamp(0), "19700101T000000Z");
+        assert_eq!(stamp(1_000_000_000_000), "20010909T014640Z");
+        assert_eq!(stamp(1_770_000_000_000), "20260202T024000Z");
+        // Sorting the names sorts the pictures.
+        assert!(stamp(1_770_000_000_000) < stamp(1_770_000_001_000));
+    }
+}

src/decoders/trx-sstv/src/demod.rs

@@ -0,0 +1,297 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Instantaneous frequency estimation.
+//!
+//! SSTV carries every pixel as a frequency between 1500 and 2300 Hz, and every
+//! line boundary as a 1200 Hz pulse, so one measurement serves the whole
+//! decoder: the frequency of the signal at each sample. A Hilbert transform
+//! FIR forms the analytic signal and the phase difference between consecutive
+//! samples gives the frequency.
+//!
+//! The same approach drives the WEFAX decoder, which maps the result straight
+//! to luminance. Here the frequency itself is the output, because the VIS
+//! header and the sync detector read tones far outside the pixel band.
+//!
+//! Block-based linear processing, per `docs/Optimization-Guidelines.md`: the
+//! FIR runs over a contiguous `[tail | samples]` buffer so the inner loop is
+//! straight indexing the compiler can vectorise.
+
+use std::f32::consts::PI;
+
+/// Taps for the Hilbert transform FIR. Odd, so the delay is a whole sample.
+const HILBERT_TAPS: usize = 65;
+
+/// Group delay of the FIR, in samples.
+const HILBERT_DELAY: usize = HILBERT_TAPS / 2;
+
+/// Taps for the input band-pass. Long enough to be worth having, short enough
+/// that its delay is a couple of milliseconds.
+const BANDPASS_TAPS: usize = 127;
+
+/// The band SSTV lives in: sync at 1200 Hz, black at 1500, white at 2300.
+const BAND_LOW_HZ: f32 = 900.0;
+const BAND_HIGH_HZ: f32 = 2700.0;
+
+/// Produces instantaneous frequency in Hz from real audio samples.
+pub struct FreqDemod {
+    /// Band-pass, applied first. A phase-difference frequency detector answers
+    /// whatever is loudest, so hiss outside the SSTV band steers the estimate
+    /// even when the signal is much stronger — the picture tears rather than
+    /// grows grainy. Every real decoder filters to the band first.
+    bandpass: Vec<f32>,
+    bandpass_tail: Vec<f32>,
+    coeffs: [f32; HILBERT_TAPS],
+    /// The last `HILBERT_TAPS - 1` input samples, priming the next block.
+    tail: Vec<f32>,
+    prev_i: f32,
+    prev_q: f32,
+    /// `sample_rate / 2π`, the constant turning phase step into Hz.
+    hz_per_radian: f32,
+}
+
+impl FreqDemod {
+    pub fn new(sample_rate: u32) -> Self {
+        Self {
+            bandpass: design_bandpass_fir(sample_rate),
+            bandpass_tail: vec![0.0; BANDPASS_TAPS - 1],
+            coeffs: design_hilbert_fir(),
+            tail: vec![0.0; HILBERT_TAPS - 1],
+            prev_i: 0.0,
+            prev_q: 0.0,
+            hz_per_radian: sample_rate as f32 / (2.0 * PI),
+        }
+    }
+
+    /// Band-pass a block, carrying the filter's state across the seam.
+    fn filter(&mut self, samples: &[f32]) -> Vec<f32> {
+        let taps = BANDPASS_TAPS;
+        let tail_len = taps - 1;
+        let mut work = Vec::with_capacity(tail_len + samples.len());
+        work.extend_from_slice(&self.bandpass_tail);
+        work.extend_from_slice(samples);
+
+        let mut out = Vec::with_capacity(samples.len());
+        for i in 0..samples.len() {
+            let window = &work[i..i + taps];
+            let mut acc = 0.0f32;
+            for k in 0..taps {
+                acc += self.bandpass[k] * window[taps - 1 - k];
+            }
+            out.push(acc);
+        }
+        let work_len = work.len();
+        self.bandpass_tail
+            .copy_from_slice(&work[work_len - tail_len..]);
+        out
+    }
+
+    /// Frequency in Hz for each input sample, appended to `out`.
+    ///
+    /// Output is delayed by the FIR's group delay, which is constant and so
+    /// affects only the absolute timing of the whole stream, not the spacing
+    /// between the events in it.
+    pub fn process_into(&mut self, samples: &[f32], out: &mut Vec<f32>) {
+        if samples.is_empty() {
+            return;
+        }
+        let samples = self.filter(samples);
+        let samples = samples.as_slice();
+        let taps = HILBERT_TAPS;
+        let tail_len = taps - 1;
+
+        let mut work = Vec::with_capacity(tail_len + samples.len());
+        work.extend_from_slice(&self.tail);
+        work.extend_from_slice(samples);
+
+        out.reserve(samples.len());
+        for i in 0..samples.len() {
+            let window = &work[i..i + taps];
+            let mut q = 0.0f32;
+            for k in 0..taps {
+                q += self.coeffs[k] * window[taps - 1 - k];
+            }
+            // In phase with the quadrature output: the input, delayed by the
+            // FIR's own group delay.
+            let i_val = window[HILBERT_DELAY];
+
+            // f = |arg(z[n] · conj(z[n-1]))| · fs / 2π
+            let di = i_val * self.prev_i + q * self.prev_q;
+            let dq = q * self.prev_i - i_val * self.prev_q;
+            out.push(dq.atan2(di).abs() * self.hz_per_radian);
+
+            self.prev_i = i_val;
+            self.prev_q = q;
+        }
+
+        let work_len = work.len();
+        self.tail.copy_from_slice(&work[work_len - tail_len..]);
+    }
+
+    pub fn reset(&mut self) {
+        self.bandpass_tail.fill(0.0);
+        self.tail.fill(0.0);
+        self.prev_i = 0.0;
+        self.prev_q = 0.0;
+    }
+}
+
+/// Boxcar mean over `window` samples, centred, returning one value per input.
+///
+/// The per-sample estimate ripples — badly at the low end of the band, where
+/// the Hilbert approximation is weakest: a clean 1200 Hz tone reads anywhere
+/// between 1110 and 1300 Hz sample to sample, though its mean is exact. Pixels
+/// are averaged over their own window and so come out right regardless, but
+/// anything that classifies a single sample by frequency — the VIS bits, the
+/// sync pulses — has to look at a mean or it is reading the ripple.
+pub fn smooth(freqs: &[f32], window: usize) -> Vec<f32> {
+    let window = window.max(1);
+    if freqs.is_empty() {
+        return Vec::new();
+    }
+    // Prefix sums in f64: a minute of audio is three million samples, and a
+    // running f32 total drifts long before that.
+    let mut prefix = Vec::with_capacity(freqs.len() + 1);
+    prefix.push(0.0f64);
+    for &freq in freqs {
+        prefix.push(prefix[prefix.len() - 1] + f64::from(freq));
+    }
+    let half = window / 2;
+    (0..freqs.len())
+        .map(|i| {
+            // Shrinks at the ends rather than reaching past them.
+            let from = i.saturating_sub(half);
+            let to = (i + window - half).min(freqs.len());
+            ((prefix[to] - prefix[from]) / (to - from) as f64) as f32
+        })
+        .collect()
+}
+
+/// Windowed-sinc band-pass over the SSTV band, Hamming-windowed and
+/// linear-phase, so every frequency in the band is delayed alike.
+fn design_bandpass_fir(sample_rate: u32) -> Vec<f32> {
+    let sr = sample_rate as f64;
+    let low = f64::from(BAND_LOW_HZ) / sr;
+    let high = (f64::from(BAND_HIGH_HZ) / sr).min(0.499);
+    let m = (BANDPASS_TAPS - 1) as f64;
+    let mid = m / 2.0;
+    let sinc = |x: f64| {
+        if x.abs() < 1e-9 {
+            1.0
+        } else {
+            (std::f64::consts::PI * x).sin() / (std::f64::consts::PI * x)
+        }
+    };
+    let mut coeffs = Vec::with_capacity(BANDPASS_TAPS);
+    for i in 0..BANDPASS_TAPS {
+        let n = i as f64 - mid;
+        // Difference of two low-passes is a band-pass.
+        let ideal = 2.0 * high * sinc(2.0 * high * n) - 2.0 * low * sinc(2.0 * low * n);
+        let window = 0.54 - 0.46 * (2.0 * std::f64::consts::PI * i as f64 / m).cos();
+        coeffs.push((ideal * window) as f32);
+    }
+    coeffs
+}
+
+/// Type III FIR approximating a 90° phase shift: h[n] = 2/(πn) for odd n,
+/// Blackman-windowed. Independent of sample rate, so the decoder can run at
+/// whatever rate the audio arrives in.
+fn design_hilbert_fir() -> [f32; HILBERT_TAPS] {
+    let mut coeffs = [0.0f32; HILBERT_TAPS];
+    let m = (HILBERT_TAPS - 1) as f64;
+    let mid = m / 2.0;
+    for (i, coeff) in coeffs.iter_mut().enumerate() {
+        let n = i as f64 - mid;
+        let ni = n.round() as i64;
+        if ni != 0 && ni % 2 != 0 {
+            let h = 2.0 / (std::f64::consts::PI * n);
+            let w = 0.42 - 0.5 * (2.0 * std::f64::consts::PI * i as f64 / m).cos()
+                + 0.08 * (4.0 * std::f64::consts::PI * i as f64 / m).cos();
+            *coeff = (h * w) as f32;
+        }
+    }
+    coeffs
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn tone(freq: f32, sample_rate: u32, samples: usize) -> Vec<f32> {
+        (0..samples)
+            .map(|n| (2.0 * PI * freq * n as f32 / sample_rate as f32).sin())
+            .collect()
+    }
+
+    /// Measured on the settled part of the output: the first `HILBERT_TAPS`
+    /// samples are the filter filling up.
+    fn measure(freq: f32, sample_rate: u32) -> f32 {
+        let mut demod = FreqDemod::new(sample_rate);
+        let mut out = Vec::new();
+        demod.process_into(
+            &tone(freq, sample_rate, sample_rate as usize / 10),
+            &mut out,
+        );
+        let settled = &out[HILBERT_TAPS * 2..];
+        settled.iter().sum::<f32>() / settled.len() as f32
+    }
+
+    #[test]
+    fn reads_the_tones_sstv_is_made_of() {
+        for rate in [8000u32, 11025, 44100, 48000] {
+            for freq in [1200.0f32, 1500.0, 1900.0, 2300.0] {
+                let measured = measure(freq, rate);
+                assert!(
+                    (measured - freq).abs() < 5.0,
+                    "{rate} Hz: {freq} Hz tone measured as {measured:.1} Hz",
+                );
+            }
+        }
+    }
+
+    /// Blocks are whatever size the audio pipeline hands over, and a tone that
+    /// straddles two of them must not produce a discontinuity at the seam.
+    #[test]
+    fn block_boundaries_do_not_disturb_the_estimate() {
+        let rate = 48_000;
+        let samples = tone(1900.0, rate, 9600);
+        let mut whole = FreqDemod::new(rate);
+        let mut expected = Vec::new();
+        whole.process_into(&samples, &mut expected);
+
+        let mut split = FreqDemod::new(rate);
+        let mut actual = Vec::new();
+        for chunk in samples.chunks(137) {
+            split.process_into(chunk, &mut actual);
+        }
+
+        assert_eq!(actual.len(), expected.len());
+        for (i, (a, b)) in actual.iter().zip(&expected).enumerate() {
+            assert!((a - b).abs() < 0.01, "sample {i}: {a} vs {b}");
+        }
+    }
+
+    #[test]
+    fn follows_a_step_between_tones_within_a_pixel() {
+        let rate = 48_000;
+        let mut samples = tone(1500.0, rate, 4800);
+        samples.extend(tone(2300.0, rate, 4800));
+        let mut demod = FreqDemod::new(rate);
+        let mut out = Vec::new();
+        demod.process_into(&samples, &mut out);
+
+        // Well before the step it reads black; well after it, white. The step
+        // itself takes the filter's length to pass through.
+        let before = out[4800 - 200..4800 - 100].iter().sum::<f32>() / 100.0;
+        let after = out[4800 + 200..4800 + 300].iter().sum::<f32>() / 100.0;
+        assert!(
+            (before - 1500.0).abs() < 10.0,
+            "before the step: {before:.1} Hz"
+        );
+        assert!(
+            (after - 2300.0).abs() < 10.0,
+            "after the step: {after:.1} Hz"
+        );
+    }
+}

src/decoders/trx-sstv/src/encode.rs

@@ -0,0 +1,238 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Turning an image into an SSTV signal.
+//!
+//! This exists so the decoder can be held to a picture rather than to a
+//! description of one: the tests encode a known image, decode the audio back
+//! and compare. Nothing in the receive path uses it.
+//!
+//! It is written to the same mode table the decoder reads, which makes a
+//! round-trip a test of the decoder and not of the timings — the timings are
+//! checked separately, against the published line durations, in [`crate::mode`].
+
+use crate::mode::{Channel, Segment, SstvMode, BLACK_HZ, SYNC_HZ, WHITE_HZ};
+
+/// A stretch of constant tone.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Tone {
+    pub hz: f32,
+    pub ms: f64,
+}
+
+/// Frequency for an 8-bit level: the inverse of [`crate::mode::level_from_hz`].
+pub fn hz_from_level(level: u8) -> f32 {
+    BLACK_HZ + (WHITE_HZ - BLACK_HZ) * f32::from(level) / 255.0
+}
+
+/// The tones of a VIS header announcing `vis`.
+pub fn vis_tones(vis: u8) -> Vec<Tone> {
+    let mut tones = vec![
+        Tone {
+            hz: 1900.0,
+            ms: 300.0,
+        },
+        Tone {
+            hz: 1200.0,
+            ms: 10.0,
+        },
+        Tone {
+            hz: 1900.0,
+            ms: 300.0,
+        },
+        Tone {
+            hz: 1200.0,
+            ms: 30.0,
+        }, // start bit
+    ];
+    let mut ones = 0;
+    for bit in 0..7 {
+        let set = vis & (1 << bit) != 0;
+        if set {
+            ones += 1;
+        }
+        tones.push(Tone {
+            hz: if set { 1100.0 } else { 1300.0 },
+            ms: 30.0,
+        });
+    }
+    // Even parity over the seven data bits.
+    tones.push(Tone {
+        hz: if ones % 2 == 1 { 1100.0 } else { 1300.0 },
+        ms: 30.0,
+    });
+    tones.push(Tone {
+        hz: 1200.0,
+        ms: 30.0,
+    }); // stop bit
+    tones
+}
+
+/// RGB source for the encoder: `width * height * 3` bytes.
+pub struct Frame<'a> {
+    pub width: usize,
+    pub height: usize,
+    pub rgb: &'a [u8],
+}
+
+impl Frame<'_> {
+    fn pixel(&self, x: usize, y: usize) -> (u8, u8, u8) {
+        let x = x.min(self.width.saturating_sub(1));
+        let y = y.min(self.height.saturating_sub(1));
+        let at = (y * self.width + x) * 3;
+        (self.rgb[at], self.rgb[at + 1], self.rgb[at + 2])
+    }
+
+    /// The colour components SSTV actually sends, for a pixel.
+    fn ycrcb(&self, x: usize, y: usize) -> (u8, u8, u8) {
+        let (r, g, b) = self.pixel(x, y);
+        let (r, g, b) = (f32::from(r), f32::from(g), f32::from(b));
+        let y_val = 16.0 + (0.003_906 * ((65.738 * r) + (129.057 * g) + (25.064 * b)));
+        let cr = 128.0 + (0.003_906 * ((112.439 * r) + (-94.154 * g) + (-18.285 * b)));
+        let cb = 128.0 + (0.003_906 * ((-37.945 * r) + (-74.494 * g) + (112.439 * b)));
+        (
+            y_val.clamp(0.0, 255.0) as u8,
+            cr.clamp(0.0, 255.0) as u8,
+            cb.clamp(0.0, 255.0) as u8,
+        )
+    }
+}
+
+/// Encode `frame` in `mode`, returning the tones of the whole transmission.
+pub fn encode_tones(mode: &SstvMode, frame: &Frame<'_>) -> Vec<Tone> {
+    let mut tones = vis_tones(mode.vis);
+    let per_line = usize::from(mode.lines_per_transmission);
+    let transmissions = usize::from(mode.height) / per_line;
+
+    for transmission in 0..transmissions {
+        let top = transmission * per_line;
+        for segment in mode.segments {
+            match *segment {
+                Segment::Sync(ms) => tones.push(Tone { hz: SYNC_HZ, ms }),
+                Segment::Gap(ms) => tones.push(Tone { hz: BLACK_HZ, ms }),
+                Segment::Scan { channel, ms } => {
+                    // A chroma scan carries fewer pixels than the image is
+                    // wide, and takes proportionally less time per pixel.
+                    let pixels = mode.scan_pixels(channel);
+                    let pixel_ms = ms / pixels as f64;
+                    for x in 0..pixels {
+                        let level = channel_level(mode, frame, channel, x, top, transmission);
+                        tones.push(Tone {
+                            hz: hz_from_level(level),
+                            ms: pixel_ms,
+                        });
+                    }
+                }
+            }
+        }
+    }
+    tones
+}
+
+fn channel_level(
+    mode: &SstvMode,
+    frame: &Frame<'_>,
+    channel: Channel,
+    x: usize,
+    top: usize,
+    transmission: usize,
+) -> u8 {
+    match channel {
+        Channel::Red => frame.pixel(x, top).0,
+        Channel::Green => frame.pixel(x, top).1,
+        Channel::Blue => frame.pixel(x, top).2,
+        Channel::LumaOdd => frame.ycrcb(x, top).0,
+        Channel::LumaEven => frame.ycrcb(x, top + 1).0,
+        Channel::ChromaR => chroma(mode, frame, x, top, true),
+        Channel::ChromaB => chroma(mode, frame, x, top, false),
+        // Robot 36 sends R-Y on odd transmitted lines and B-Y on even ones.
+        Channel::ChromaAlternating => chroma(mode, frame, x, top, transmission.is_multiple_of(2)),
+    }
+}
+
+/// Chroma scans are half the width of the image in the Robot modes, so each
+/// value covers two pixels; PD averages the two image lines of the pair too.
+fn chroma(mode: &SstvMode, frame: &Frame<'_>, x: usize, top: usize, want_cr: bool) -> u8 {
+    let scale = usize::from(mode.width) / mode.scan_pixels(Channel::ChromaR).max(1);
+    let x0 = x * scale;
+    let mut total = 0u32;
+    let mut count = 0u32;
+    let rows = usize::from(mode.lines_per_transmission);
+    for row in 0..rows {
+        for dx in 0..scale {
+            let (_, cr, cb) = frame.ycrcb(x0 + dx, top + row);
+            total += u32::from(if want_cr { cr } else { cb });
+            count += 1;
+        }
+    }
+    (total / count.max(1)) as u8
+}
+
+/// Render tones to audio at `sample_rate`, with continuous phase so the
+/// demodulator sees no step at a tone boundary that isn't in the signal.
+pub fn render(tones: &[Tone], sample_rate: u32) -> Vec<f32> {
+    let sr = f64::from(sample_rate);
+    let mut out =
+        Vec::with_capacity((tones.iter().map(|t| t.ms).sum::<f64>() / 1000.0 * sr) as usize);
+    let mut phase = 0.0f64;
+    // Each tone's *end* is rounded to a sample, rather than its length: a
+    // pixel of 25.5 samples rounded up on its own puts a whole line 600
+    // samples late by the end of it, which is a timing error no receiver
+    // should have to chase and no transmitter would produce.
+    let mut elapsed_ms = 0.0f64;
+    let mut emitted = 0usize;
+    for tone in tones {
+        elapsed_ms += tone.ms;
+        let end = (elapsed_ms / 1000.0 * sr).round() as usize;
+        let samples = end.saturating_sub(emitted);
+        emitted = end;
+        let step = 2.0 * std::f64::consts::PI * f64::from(tone.hz) / sr;
+        for _ in 0..samples {
+            out.push(phase.sin() as f32);
+            phase += step;
+            if phase > std::f64::consts::TAU {
+                phase -= std::f64::consts::TAU;
+            }
+        }
+    }
+    out
+}
+
+/// Encode a frame straight to audio.
+pub fn encode(mode: &SstvMode, frame: &Frame<'_>, sample_rate: u32) -> Vec<f32> {
+    render(&encode_tones(mode, frame), sample_rate)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::mode::{level_from_hz, mode_for_vis};
+
+    #[test]
+    fn levels_survive_the_trip_through_frequency() {
+        for level in [0u8, 1, 64, 128, 200, 255] {
+            assert_eq!(level_from_hz(hz_from_level(level)), level);
+        }
+    }
+
+    #[test]
+    fn a_transmission_lasts_as_long_as_the_mode_says() {
+        let mode = mode_for_vis(44).expect("Martin M1");
+        let rgb = vec![128u8; 320 * 256 * 3];
+        let frame = Frame {
+            width: 320,
+            height: 256,
+            rgb: &rgb,
+        };
+        let audio = encode(mode, &frame, 48_000);
+        // Header plus 256 lines, within a line of the published duration.
+        let header_s = 0.94;
+        let expected = header_s + mode.frame_secs();
+        let actual = audio.len() as f64 / 48_000.0;
+        assert!(
+            (actual - expected).abs() < mode.line_ms / 1000.0,
+            "encoded {actual:.2} s, expected {expected:.2} s",
+        );
+    }
+}

src/decoders/trx-sstv/src/image.rs

@@ -0,0 +1,150 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Assembling decoded lines into an image, and getting it out of the process.
+//!
+//! Rows arrive one at a time and the picture is worth looking at before it is
+//! finished, so the assembler holds a full-size RGB canvas from the start and
+//! fills it in. An unfinished frame is grey below the last decoded row rather
+//! than black, which reads as "not here yet" instead of "received as black".
+
+use std::path::{Path, PathBuf};
+
+use base64::Engine;
+
+/// Value the canvas starts at: mid-grey, for rows not yet received.
+const UNWRITTEN: u8 = 96;
+
+pub struct ImageCanvas {
+    width: usize,
+    height: usize,
+    rgb: Vec<u8>,
+    /// Highest row index written, plus one.
+    filled_rows: usize,
+}
+
+impl ImageCanvas {
+    pub fn new(width: usize, height: usize) -> Self {
+        Self {
+            width,
+            height,
+            rgb: vec![UNWRITTEN; width * height * 3],
+            filled_rows: 0,
+        }
+    }
+
+    pub fn width(&self) -> usize {
+        self.width
+    }
+
+    pub fn height(&self) -> usize {
+        self.height
+    }
+
+    /// Rows written so far.
+    pub fn filled_rows(&self) -> usize {
+        self.filled_rows
+    }
+
+    /// Write one row of RGB triples. Rows past the bottom of the image are
+    /// dropped: a transmission that runs long is not a reason to grow.
+    pub fn put_row(&mut self, y: usize, row: &[u8]) {
+        if y >= self.height {
+            return;
+        }
+        let at = y * self.width * 3;
+        let take = row.len().min(self.width * 3);
+        self.rgb[at..at + take].copy_from_slice(&row[..take]);
+        self.filled_rows = self.filled_rows.max(y + 1);
+    }
+
+    pub fn row(&self, y: usize) -> Option<&[u8]> {
+        if y >= self.height {
+            return None;
+        }
+        let at = y * self.width * 3;
+        Some(&self.rgb[at..at + self.width * 3])
+    }
+
+    pub fn rgb(&self) -> &[u8] {
+        &self.rgb
+    }
+
+    /// Encode the canvas as a PNG.
+    pub fn to_png(&self) -> Result<Vec<u8>, String> {
+        let mut out = Vec::new();
+        {
+            let mut encoder = png::Encoder::new(&mut out, self.width as u32, self.height as u32);
+            encoder.set_color(png::ColorType::Rgb);
+            encoder.set_depth(png::BitDepth::Eight);
+            let mut writer = encoder
+                .write_header()
+                .map_err(|e| format!("PNG header: {e}"))?;
+            writer
+                .write_image_data(&self.rgb)
+                .map_err(|e| format!("PNG data: {e}"))?;
+        }
+        Ok(out)
+    }
+
+    /// The PNG, base64-encoded for the journey to a browser.
+    pub fn to_png_base64(&self) -> Result<String, String> {
+        Ok(base64::engine::general_purpose::STANDARD.encode(self.to_png()?))
+    }
+
+    /// Write the PNG into `dir`, named for when and where it was received.
+    pub fn save_png(
+        &self,
+        dir: &Path,
+        freq_hz: u64,
+        mode_name: &str,
+        stamp: &str,
+    ) -> Result<PathBuf, String> {
+        std::fs::create_dir_all(dir).map_err(|e| format!("create {}: {e}", dir.display()))?;
+        let slug: String = mode_name
+            .chars()
+            .map(|c| if c.is_ascii_alphanumeric() { c } else { '-' })
+            .collect();
+        let path = dir.join(format!("SSTV_{stamp}_{freq_hz}_{slug}.png"));
+        std::fs::write(&path, self.to_png()?)
+            .map_err(|e| format!("write {}: {e}", path.display()))?;
+        Ok(path)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn rows_land_where_they_are_put_and_the_rest_stays_unwritten() {
+        let mut canvas = ImageCanvas::new(4, 3);
+        canvas.put_row(1, &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]);
+        assert_eq!(canvas.row(1).unwrap()[0..3], [1, 2, 3]);
+        assert_eq!(canvas.row(0).unwrap()[0], UNWRITTEN);
+        assert_eq!(canvas.filled_rows(), 2);
+    }
+
+    #[test]
+    fn a_row_past_the_bottom_is_dropped_rather_than_growing_the_image() {
+        let mut canvas = ImageCanvas::new(2, 2);
+        canvas.put_row(9, &[1, 2, 3, 4, 5, 6]);
+        assert_eq!(canvas.filled_rows(), 0);
+        assert_eq!(canvas.rgb().len(), 2 * 2 * 3);
+    }
+
+    #[test]
+    fn encodes_a_png_a_decoder_can_read_back() {
+        let mut canvas = ImageCanvas::new(2, 2);
+        canvas.put_row(0, &[255, 0, 0, 0, 255, 0]);
+        let png_bytes = canvas.to_png().expect("png");
+        let decoder = png::Decoder::new(png_bytes.as_slice());
+        let mut reader = decoder.read_info().expect("png info");
+        let mut buf = vec![0; reader.output_buffer_size()];
+        let info = reader.next_frame(&mut buf).expect("png frame");
+        assert_eq!((info.width, info.height), (2, 2));
+        assert_eq!(&buf[0..6], &[255, 0, 0, 0, 255, 0]);
+        assert!(!canvas.to_png_base64().expect("base64").is_empty());
+    }
+}

src/decoders/trx-sstv/src/lib.rs

@@ -0,0 +1,36 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! SSTV (Slow-Scan Television) decoder.
+//!
+//! Pure Rust, covering Martin, Scottie, Robot, PD and Wraase SC2-180, with the
+//! mode taken from the VIS header that precedes every transmission. Rows are
+//! emitted as they arrive so a picture can be watched building up.
+//!
+//! ```no_run
+//! use trx_sstv::{SstvConfig, SstvDecoder, SstvEvent};
+//!
+//! let mut decoder = SstvDecoder::new(48_000, SstvConfig::default());
+//! # let audio: Vec<f32> = Vec::new();
+//! for event in decoder.process_samples(&audio) {
+//!     match event {
+//!         SstvEvent::Started { mode, .. } => println!("receiving {mode}"),
+//!         SstvEvent::Row { line, .. } => println!("line {line}"),
+//!         SstvEvent::Complete(image) => println!("{} lines", image.lines),
+//!     }
+//! }
+//! ```
+
+pub mod config;
+pub mod decoder;
+pub mod demod;
+pub mod encode;
+pub mod image;
+pub mod mode;
+pub mod vis;
+
+pub use config::SstvConfig;
+pub use decoder::{SstvDecoder, SstvEvent, SstvImage};
+pub use image::ImageCanvas;
+pub use mode::{mode_for_vis, SstvMode, MODES};

src/decoders/trx-sstv/src/mode.rs

@@ -0,0 +1,615 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! SSTV mode table: what a VIS code means in timings, geometry and colour.
+//!
+//! Every mode transmits a line as a sequence of *segments* — a sync pulse, a
+//! porch or separator at a fixed tone, and one scan per colour channel. The
+//! decoder needs only the segment layout and the offset of each scan within
+//! the line, so that is what a [`SstvMode`] is: a list of segments plus the
+//! rules for turning the scans back into pixels.
+//!
+//! Timings follow the published mode specifications (JL Barber, N7CXI,
+//! "Proposal for SSTV Mode Specifications", 2000), which is the same table
+//! MMSSTV, QSSTV and slowrx work from.
+
+/// Tone that marks a line boundary, in Hz.
+pub const SYNC_HZ: f32 = 1200.0;
+/// Tone for black, in Hz.
+pub const BLACK_HZ: f32 = 1500.0;
+/// Tone for white, in Hz.
+pub const WHITE_HZ: f32 = 2300.0;
+
+/// What a scan segment carries.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Channel {
+    Red,
+    Green,
+    Blue,
+    /// Luminance for the odd (first) image line of the pair.
+    LumaOdd,
+    /// Luminance for the even (second) image line of a PD pair.
+    LumaEven,
+    /// R-Y chrominance.
+    ChromaR,
+    /// B-Y chrominance.
+    ChromaB,
+    /// Robot 36 alternates R-Y and B-Y between transmitted lines: odd lines
+    /// carry R-Y, even lines B-Y, and each is held over both.
+    ChromaAlternating,
+}
+
+/// One piece of a transmitted line.
+#[derive(Debug, Clone, Copy)]
+pub enum Segment {
+    /// Sync pulse at [`SYNC_HZ`].
+    Sync(f64),
+    /// Porch, separator or gap at a fixed tone; the tone itself is not decoded.
+    Gap(f64),
+    /// A scan carrying pixels for one channel.
+    Scan { channel: Channel, ms: f64 },
+}
+
+impl Segment {
+    pub fn duration_ms(&self) -> f64 {
+        match *self {
+            Segment::Sync(ms) | Segment::Gap(ms) => ms,
+            Segment::Scan { ms, .. } => ms,
+        }
+    }
+}
+
+/// How the scans of a line become pixels.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ColorModel {
+    /// Scans are red, green and blue directly (Martin, Scottie, Wraase).
+    Rgb,
+    /// Y plus one alternating chroma channel per line (Robot 36).
+    YCrCbAlternating,
+    /// Y, R-Y and B-Y in every line (Robot 72).
+    YCrCb,
+    /// Two image lines per transmitted line: Y odd, R-Y, B-Y, Y even (PD).
+    YCrCbPaired,
+}
+
+/// A decodable SSTV mode.
+#[derive(Debug, Clone)]
+pub struct SstvMode {
+    /// VIS code as sent in the header.
+    pub vis: u8,
+    /// Human-readable name, e.g. "Martin M1".
+    pub name: &'static str,
+    /// Pixels across.
+    pub width: u16,
+    /// Image lines in a full frame.
+    pub height: u16,
+    /// Transmitted line duration in milliseconds.
+    pub line_ms: f64,
+    /// Segments in transmission order.
+    pub segments: &'static [Segment],
+    pub color: ColorModel,
+    /// Image lines produced by one transmitted line (2 for PD, otherwise 1).
+    pub lines_per_transmission: u16,
+    /// Offset from the start of a line to the leading edge of its sync pulse.
+    /// Zero for most modes; Scottie sends the sync in the middle of the line,
+    /// so a line detected at its sync starts before it.
+    pub sync_offset_ms: f64,
+}
+
+impl SstvMode {
+    /// Total of every segment, which must equal [`SstvMode::line_ms`].
+    pub fn segments_ms(&self) -> f64 {
+        self.segments.iter().map(Segment::duration_ms).sum()
+    }
+
+    /// Start offset, in milliseconds from the line start, of each scan.
+    pub fn scans(&self) -> Vec<(Channel, f64, f64)> {
+        let mut out = Vec::new();
+        let mut at = 0.0;
+        for segment in self.segments {
+            if let Segment::Scan { channel, ms } = *segment {
+                out.push((channel, at, ms));
+            }
+            at += segment.duration_ms();
+        }
+        out
+    }
+
+    /// Pixels carried by a scan of this channel.
+    ///
+    /// Chroma is sent at half the width in the Robot modes — the eye takes
+    /// colour more coarsely than brightness, and the saving is what makes 36
+    /// seconds possible. PD sends chroma at full width and saves its time by
+    /// sharing one pair of chroma scans between two image lines instead.
+    pub fn scan_pixels(&self, channel: Channel) -> usize {
+        let width = usize::from(self.width);
+        match channel {
+            Channel::ChromaR | Channel::ChromaB | Channel::ChromaAlternating
+                if self.color != ColorModel::YCrCbPaired =>
+            {
+                width / 2
+            }
+            _ => width,
+        }
+    }
+
+    /// Seconds a full frame takes to send.
+    pub fn frame_secs(&self) -> f64 {
+        self.line_ms * f64::from(self.height) / f64::from(self.lines_per_transmission) / 1000.0
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Martin — sync, porch, then green, blue, red, each followed by a separator.
+// ---------------------------------------------------------------------------
+
+const MARTIN_M1: &[Segment] = &[
+    Segment::Sync(4.862),
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 146.432,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 146.432,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 146.432,
+    },
+    Segment::Gap(0.572),
+];
+
+const MARTIN_M2: &[Segment] = &[
+    Segment::Sync(4.862),
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 73.216,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 73.216,
+    },
+    Segment::Gap(0.572),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 73.216,
+    },
+    Segment::Gap(0.572),
+];
+
+// ---------------------------------------------------------------------------
+// Scottie — the sync pulse sits between the blue and red scans, so a line
+// starts one separator before the green scan and the sync of the *previous*
+// line is what marks it.
+// ---------------------------------------------------------------------------
+
+const SCOTTIE_S1: &[Segment] = &[
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 138.240,
+    },
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 138.240,
+    },
+    Segment::Sync(9.0),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 138.240,
+    },
+];
+
+const SCOTTIE_S2: &[Segment] = &[
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 88.064,
+    },
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 88.064,
+    },
+    Segment::Sync(9.0),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 88.064,
+    },
+];
+
+const SCOTTIE_DX: &[Segment] = &[
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 345.6,
+    },
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 345.6,
+    },
+    Segment::Sync(9.0),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 345.6,
+    },
+];
+
+/// Scottie's sync arrives after the green and blue scans: 1.5 + 138.24 + 1.5 +
+/// 138.24 for S1, and the equivalent for the others.
+const fn scottie_sync_offset(scan_ms: f64) -> f64 {
+    1.5 + scan_ms + 1.5 + scan_ms
+}
+
+// ---------------------------------------------------------------------------
+// Robot — luminance plus chrominance, the chroma scans at half the width.
+// ---------------------------------------------------------------------------
+
+const ROBOT_36: &[Segment] = &[
+    Segment::Sync(9.0),
+    Segment::Gap(3.0),
+    Segment::Scan {
+        channel: Channel::LumaOdd,
+        ms: 88.0,
+    },
+    Segment::Gap(4.5),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::ChromaAlternating,
+        ms: 44.0,
+    },
+];
+
+const ROBOT_72: &[Segment] = &[
+    Segment::Sync(9.0),
+    Segment::Gap(3.0),
+    Segment::Scan {
+        channel: Channel::LumaOdd,
+        ms: 138.0,
+    },
+    Segment::Gap(4.5),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::ChromaR,
+        ms: 69.0,
+    },
+    Segment::Gap(4.5),
+    Segment::Gap(1.5),
+    Segment::Scan {
+        channel: Channel::ChromaB,
+        ms: 69.0,
+    },
+];
+
+// ---------------------------------------------------------------------------
+// PD — one transmitted line carries two image lines: the luminance of both,
+// with a single pair of chroma scans shared between them.
+// ---------------------------------------------------------------------------
+
+macro_rules! pd_segments {
+    ($name:ident, $scan:expr) => {
+        const $name: &[Segment] = &[
+            Segment::Sync(20.0),
+            Segment::Gap(2.08),
+            Segment::Scan {
+                channel: Channel::LumaOdd,
+                ms: $scan,
+            },
+            Segment::Scan {
+                channel: Channel::ChromaR,
+                ms: $scan,
+            },
+            Segment::Scan {
+                channel: Channel::ChromaB,
+                ms: $scan,
+            },
+            Segment::Scan {
+                channel: Channel::LumaEven,
+                ms: $scan,
+            },
+        ];
+    };
+}
+
+pd_segments!(PD_50, 91.520);
+pd_segments!(PD_90, 170.240);
+pd_segments!(PD_120, 121.600);
+pd_segments!(PD_160, 195.584);
+pd_segments!(PD_180, 183.040);
+pd_segments!(PD_240, 244.672);
+pd_segments!(PD_290, 228.800);
+
+// ---------------------------------------------------------------------------
+// Wraase SC2-180 — red, green, blue in that order after one porch.
+// ---------------------------------------------------------------------------
+
+const WRAASE_SC2_180: &[Segment] = &[
+    Segment::Sync(5.5225),
+    Segment::Gap(0.5),
+    Segment::Scan {
+        channel: Channel::Red,
+        ms: 235.0,
+    },
+    Segment::Scan {
+        channel: Channel::Green,
+        ms: 235.0,
+    },
+    Segment::Scan {
+        channel: Channel::Blue,
+        ms: 235.0,
+    },
+];
+
+/// Every mode this decoder knows, in VIS order.
+pub static MODES: &[SstvMode] = &[
+    SstvMode {
+        vis: 8,
+        name: "Robot 36",
+        width: 320,
+        height: 240,
+        line_ms: 150.0,
+        segments: ROBOT_36,
+        color: ColorModel::YCrCbAlternating,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 12,
+        name: "Robot 72",
+        width: 320,
+        height: 240,
+        line_ms: 300.0,
+        segments: ROBOT_72,
+        color: ColorModel::YCrCb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 40,
+        name: "Martin M2",
+        width: 320,
+        height: 256,
+        line_ms: 226.798,
+        segments: MARTIN_M2,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 44,
+        name: "Martin M1",
+        width: 320,
+        height: 256,
+        line_ms: 446.446,
+        segments: MARTIN_M1,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 55,
+        name: "Wraase SC2-180",
+        width: 320,
+        height: 256,
+        line_ms: 711.0225,
+        segments: WRAASE_SC2_180,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 56,
+        name: "Scottie S2",
+        width: 320,
+        height: 256,
+        line_ms: 277.692,
+        segments: SCOTTIE_S2,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: scottie_sync_offset(88.064),
+    },
+    SstvMode {
+        vis: 60,
+        name: "Scottie S1",
+        width: 320,
+        height: 256,
+        line_ms: 428.22,
+        segments: SCOTTIE_S1,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: scottie_sync_offset(138.240),
+    },
+    SstvMode {
+        vis: 76,
+        name: "Scottie DX",
+        width: 320,
+        height: 256,
+        line_ms: 1050.3,
+        segments: SCOTTIE_DX,
+        color: ColorModel::Rgb,
+        lines_per_transmission: 1,
+        sync_offset_ms: scottie_sync_offset(345.6),
+    },
+    SstvMode {
+        vis: 93,
+        name: "PD50",
+        width: 320,
+        height: 256,
+        line_ms: 388.16,
+        segments: PD_50,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 94,
+        name: "PD290",
+        width: 800,
+        height: 616,
+        line_ms: 937.28,
+        segments: PD_290,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 95,
+        name: "PD120",
+        width: 640,
+        height: 496,
+        line_ms: 508.48,
+        segments: PD_120,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 96,
+        name: "PD180",
+        width: 640,
+        height: 496,
+        line_ms: 754.24,
+        segments: PD_180,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 97,
+        name: "PD240",
+        width: 640,
+        height: 496,
+        line_ms: 1000.768,
+        segments: PD_240,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 98,
+        name: "PD160",
+        width: 512,
+        height: 400,
+        line_ms: 804.416,
+        segments: PD_160,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+    SstvMode {
+        vis: 99,
+        name: "PD90",
+        width: 320,
+        height: 256,
+        line_ms: 703.04,
+        segments: PD_90,
+        color: ColorModel::YCrCbPaired,
+        lines_per_transmission: 2,
+        sync_offset_ms: 0.0,
+    },
+];
+
+/// Look a mode up by the VIS code that announced it.
+pub fn mode_for_vis(vis: u8) -> Option<&'static SstvMode> {
+    MODES.iter().find(|mode| mode.vis == vis)
+}
+
+/// Map an instantaneous frequency to an 8-bit level: 1500 Hz is black, 2300 Hz
+/// white. Frequencies outside the band clamp rather than wrap, so a sync pulse
+/// that lands inside a scan reads as black instead of as bright noise.
+pub fn level_from_hz(hz: f32) -> u8 {
+    let level = (hz - BLACK_HZ) * (255.0 / (WHITE_HZ - BLACK_HZ));
+    level.clamp(0.0, 255.0).round() as u8
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // The segment list and the published line time are two statements of the
+    // same fact, entered by hand from the specification. If a digit is wrong in
+    // one it is unlikely to be wrong identically in the other.
+    #[test]
+    fn segments_add_up_to_the_published_line_time() {
+        for mode in MODES {
+            let sum = mode.segments_ms();
+            assert!(
+                (sum - mode.line_ms).abs() < 0.001,
+                "{}: segments total {:.4} ms, line time says {:.4} ms",
+                mode.name,
+                sum,
+                mode.line_ms,
+            );
+        }
+    }
+
+    #[test]
+    fn vis_codes_are_unique_and_resolvable() {
+        for mode in MODES {
+            assert_eq!(mode_for_vis(mode.vis).map(|m| m.name), Some(mode.name));
+        }
+        let mut codes: Vec<u8> = MODES.iter().map(|m| m.vis).collect();
+        codes.sort_unstable();
+        let count = codes.len();
+        codes.dedup();
+        assert_eq!(codes.len(), count, "two modes claim the same VIS code");
+    }
+
+    #[test]
+    fn every_mode_scans_enough_channels_for_its_colour_model() {
+        for mode in MODES {
+            let scans = mode.scans();
+            let expected = match mode.color {
+                ColorModel::Rgb => 3,
+                ColorModel::YCrCbAlternating => 2,
+                ColorModel::YCrCb => 3,
+                ColorModel::YCrCbPaired => 4,
+            };
+            assert_eq!(
+                scans.len(),
+                expected,
+                "{} has {} scans",
+                mode.name,
+                scans.len()
+            );
+        }
+    }
+
+    // Frame durations are what operators know these modes by — the number in
+    // the name is the number of seconds.
+    #[test]
+    fn frame_durations_match_the_names() {
+        for (vis, secs) in [(8u8, 36.0), (12, 72.0), (93, 50.0), (99, 90.0), (95, 126.0)] {
+            let mode = mode_for_vis(vis).expect("mode in table");
+            let actual = mode.frame_secs();
+            assert!(
+                (actual - secs).abs() < 1.5,
+                "{} takes {:.1} s, expected about {:.0} s",
+                mode.name,
+                actual,
+                secs,
+            );
+        }
+    }
+
+    #[test]
+    fn levels_span_black_to_white_and_clamp_outside() {
+        assert_eq!(level_from_hz(BLACK_HZ), 0);
+        assert_eq!(level_from_hz(WHITE_HZ), 255);
+        assert_eq!(level_from_hz(1900.0), 128);
+        assert_eq!(level_from_hz(SYNC_HZ), 0, "a sync pulse must read as black");
+        assert_eq!(level_from_hz(3000.0), 255);
+    }
+}

src/decoders/trx-sstv/src/vis.rs

@@ -0,0 +1,236 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! VIS header detection.
+//!
+//! Every transmission announces its mode in a fixed preamble:
+//!
+//! | Part | Tone | Duration |
+//! |------|------|----------|
+//! | Leader | 1900 Hz | 300 ms |
+//! | Break | 1200 Hz | 10 ms |
+//! | Leader | 1900 Hz | 300 ms |
+//! | Start bit | 1200 Hz | 30 ms |
+//! | 7 data bits, LSB first | 1100 Hz = 1, 1300 Hz = 0 | 30 ms each |
+//! | Even parity | as above | 30 ms |
+//! | Stop bit | 1200 Hz | 30 ms |
+//!
+//! The detector looks for the start bit standing behind a leader, reads the
+//! eight bits that follow, and checks the parity. Parity is the only integrity
+//! check the header has, so a code that fails it is discarded rather than
+//! guessed at — decoding 114 seconds of Martin M1 as Scottie DX produces a
+//! convincing-looking image of nothing.
+
+/// Tone durations, in milliseconds.
+const BIT_MS: f64 = 30.0;
+const LEADER_MS: f64 = 300.0;
+
+/// How far a tone may sit from its nominal frequency and still be recognised.
+/// Wide enough for a rig tuned a little off, narrow enough that 1100, 1200,
+/// 1300 and 1900 Hz stay distinct.
+const TONE_TOLERANCE_HZ: f32 = 60.0;
+
+const LEADER_HZ: f32 = 1900.0;
+const START_HZ: f32 = 1200.0;
+const ONE_HZ: f32 = 1100.0;
+const ZERO_HZ: f32 = 1300.0;
+
+/// A VIS header found in the stream.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct VisHit {
+    /// The code, which names the mode.
+    pub code: u8,
+    /// Index just past the stop bit: where the image itself begins.
+    pub image_start: usize,
+}
+
+fn near(freq: f32, target: f32) -> bool {
+    (freq - target).abs() <= TONE_TOLERANCE_HZ
+}
+
+/// Mean frequency over the middle 60% of a bit cell, which keeps the filter's
+/// transitions at either edge out of the measurement.
+fn bit_frequency(freqs: &[f32], start: f64, samples_per_bit: f64) -> Option<f32> {
+    let from = (start + samples_per_bit * 0.2).round() as usize;
+    let to = (start + samples_per_bit * 0.8).round() as usize;
+    if to <= from || to > freqs.len() {
+        return None;
+    }
+    let window = &freqs[from..to];
+    Some(window.iter().sum::<f32>() / window.len() as f32)
+}
+
+/// Search `freqs` for a VIS header, starting at `from`.
+///
+/// Returns the first header whose parity checks out. `freqs` is instantaneous
+/// frequency in Hz, one entry per audio sample.
+pub fn find_vis(freqs: &[f32], sample_rate: u32, from: usize) -> Option<VisHit> {
+    let sr = f64::from(sample_rate);
+    // Header tones are 10 ms at the shortest, so a millisecond of averaging
+    // costs nothing and takes the demodulator's ripple — ±95 Hz at 1200 Hz —
+    // out of tones that are 100 Hz apart.
+    let smoothed = crate::demod::smooth(freqs, (sr / 1000.0).round() as usize);
+    let freqs = smoothed.as_slice();
+    let samples_per_bit = BIT_MS / 1000.0 * sr;
+    let leader_samples = (LEADER_MS / 1000.0 * sr) as usize;
+    // The start bit must be at least this long to be one.
+    let min_start_run = (samples_per_bit * 0.7) as usize;
+
+    // A leader has to precede the start bit. Half of one is enough evidence,
+    // and asking for less than the full 300 ms means the search still works on
+    // a buffer that begins part-way through the header.
+    let leader_needed = leader_samples / 2;
+
+    // The bits themselves may run to the very end of what has arrived so far;
+    // reading them is what decides whether there is enough, not this bound.
+    let mut i = from.max(leader_needed);
+    while i < freqs.len() {
+        if !near(freqs[i], START_HZ) {
+            i += 1;
+            continue;
+        }
+        // Measure the run of start tone.
+        let mut run = 0usize;
+        while i + run < freqs.len() && near(freqs[i + run], START_HZ) {
+            run += 1;
+        }
+        if run < min_start_run {
+            i += run.max(1);
+            continue;
+        }
+
+        // What came before it: the leader. Sampled rather than scanned in
+        // full, since only its identity matters, not its exact length.
+        let leader_from = i - leader_needed;
+        let leader_hits = freqs[leader_from..i]
+            .iter()
+            .step_by(16)
+            .filter(|&&f| near(f, LEADER_HZ))
+            .count();
+        let leader_total = freqs[leader_from..i].iter().step_by(16).count();
+        if leader_total == 0 || (leader_hits as f64) < 0.7 * leader_total as f64 {
+            i += run;
+            continue;
+        }
+
+        // Bits follow the start bit, which the run just measured. Use the run's
+        // own end rather than a nominal offset, so a start bit stretched or
+        // clipped by the filter does not shift every bit after it.
+        let bits_start = (i + run) as f64;
+        let mut bits = [false; 8];
+        let mut readable = true;
+        for (index, bit) in bits.iter_mut().enumerate() {
+            let at = bits_start + samples_per_bit * index as f64;
+            match bit_frequency(freqs, at, samples_per_bit) {
+                Some(freq) if near(freq, ONE_HZ) => *bit = true,
+                Some(freq) if near(freq, ZERO_HZ) => *bit = false,
+                _ => {
+                    readable = false;
+                    break;
+                }
+            }
+        }
+        if !readable {
+            i += run;
+            continue;
+        }
+
+        // Seven data bits, LSB first, then even parity over them.
+        let code = bits[..7]
+            .iter()
+            .enumerate()
+            .fold(0u8, |acc, (index, &set)| acc | (u8::from(set) << index));
+        let ones = bits[..7].iter().filter(|&&b| b).count() + usize::from(bits[7]);
+        if ones % 2 != 0 {
+            i += run;
+            continue;
+        }
+
+        // Past the stop bit is the image.
+        let image_start = (bits_start + samples_per_bit * 9.0).round() as usize;
+        return Some(VisHit { code, image_start });
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::encode::{vis_tones, Tone};
+
+    fn freqs_from_tones(tones: &[Tone], sample_rate: u32) -> Vec<f32> {
+        let mut out = Vec::new();
+        for tone in tones {
+            let samples = (tone.ms / 1000.0 * f64::from(sample_rate)).round() as usize;
+            out.extend(std::iter::repeat_n(tone.hz, samples));
+        }
+        out
+    }
+
+    #[test]
+    fn reads_every_code_the_mode_table_knows() {
+        for mode in crate::mode::MODES {
+            let freqs = freqs_from_tones(&vis_tones(mode.vis), 48_000);
+            let hit = find_vis(&freqs, 48_000, 0)
+                .unwrap_or_else(|| panic!("{} header not found", mode.name));
+            assert_eq!(
+                hit.code, mode.vis,
+                "{} decoded as VIS {}",
+                mode.name, hit.code
+            );
+        }
+    }
+
+    #[test]
+    fn the_image_starts_after_the_stop_bit() {
+        let sample_rate = 48_000;
+        let freqs = freqs_from_tones(&vis_tones(44), sample_rate);
+        let hit = find_vis(&freqs, sample_rate, 0).expect("header");
+        // Header is 300 + 10 + 300 ms of leader and break, then ten 30 ms bits.
+        let expected = ((300.0 + 10.0 + 300.0 + 300.0) / 1000.0 * f64::from(sample_rate)) as usize;
+        let slack = sample_rate as usize / 100; // 10 ms
+        assert!(
+            hit.image_start.abs_diff(expected) < slack,
+            "image starts at {}, expected about {expected}",
+            hit.image_start,
+        );
+    }
+
+    #[test]
+    fn a_header_with_broken_parity_is_not_a_header() {
+        let sample_rate = 48_000;
+        let mut tones = vis_tones(44);
+        // Flip the parity bit alone: seven data bits still say Martin M1, but
+        // nothing now vouches for them.
+        let parity = tones.len() - 2;
+        tones[parity].hz = if tones[parity].hz == ONE_HZ {
+            ZERO_HZ
+        } else {
+            ONE_HZ
+        };
+        let freqs = freqs_from_tones(&tones, sample_rate);
+        assert_eq!(find_vis(&freqs, sample_rate, 0), None);
+    }
+
+    #[test]
+    fn tones_without_a_leader_are_not_a_header() {
+        let sample_rate = 48_000;
+        let mut tones = vis_tones(44);
+        // Same bits, but the leader before them is a pixel-band tone — which is
+        // what a passing image looks like.
+        tones[0].hz = 2000.0;
+        tones[2].hz = 2000.0;
+        let freqs = freqs_from_tones(&tones, sample_rate);
+        assert_eq!(find_vis(&freqs, sample_rate, 0), None);
+    }
+
+    #[test]
+    fn a_header_part_way_into_the_buffer_is_still_found() {
+        let sample_rate = 48_000;
+        let mut freqs = vec![1750.0f32; sample_rate as usize]; // a second of picture
+        freqs.extend(freqs_from_tones(&vis_tones(60), sample_rate));
+        let hit = find_vis(&freqs, sample_rate, 0).expect("header");
+        assert_eq!(hit.code, 60);
+    }
+}

src/decoders/trx-sstv/tests/round_trip.rs

@@ -0,0 +1,384 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Decode what was encoded, and compare the pictures.
+//!
+//! A decoder for a picture format can only really be tested against a picture.
+//! These tests build a test card, transmit it in each mode through the
+//! encoder, and hold the decoder to what comes back — pixel by pixel, with a
+//! tolerance that accounts for the round trip through frequency and, for the
+//! colour modes, through a chroma channel at half the width.
+//!
+//! What this does not test is the timing table itself: the encoder reads the
+//! same numbers as the decoder, so a wrong line duration would cancel out.
+//! That is checked in `mode.rs` against the published line times instead.
+
+use trx_sstv::encode::{encode, Frame};
+use trx_sstv::mode::mode_for_vis;
+use trx_sstv::{SstvConfig, SstvDecoder, SstvEvent, SstvImage};
+
+const SAMPLE_RATE: u32 = 48_000;
+
+/// A test card with something for every part of the decoder to get wrong:
+/// vertical colour bars catch channels swapped or shifted, the horizontal
+/// gradient catches a line-timing drift, and the corner blocks catch a picture
+/// that arrives upside down or mirrored.
+fn test_card(width: usize, height: usize) -> Vec<u8> {
+    let mut rgb = vec![0u8; width * height * 3];
+    let bars: [(u8, u8, u8); 8] = [
+        (255, 255, 255),
+        (255, 255, 0),
+        (0, 255, 255),
+        (0, 255, 0),
+        (255, 0, 255),
+        (255, 0, 0),
+        (0, 0, 255),
+        (0, 0, 0),
+    ];
+    for y in 0..height {
+        for x in 0..width {
+            let at = (y * width + x) * 3;
+            let (r, g, b) = if y < height / 2 {
+                bars[x * bars.len() / width]
+            } else {
+                let ramp = (x * 255 / width.max(1)) as u8;
+                let down = (y * 255 / height.max(1)) as u8;
+                (ramp, down, 255 - ramp)
+            };
+            rgb[at] = r;
+            rgb[at + 1] = g;
+            rgb[at + 2] = b;
+        }
+    }
+    // Corner marks: red top-left, blue bottom-right.
+    for y in 0..height.min(8) {
+        for x in 0..width.min(8) {
+            let at = (y * width + x) * 3;
+            rgb[at] = 255;
+            rgb[at + 1] = 0;
+            rgb[at + 2] = 0;
+        }
+    }
+    for y in height.saturating_sub(8)..height {
+        for x in width.saturating_sub(8)..width {
+            let at = (y * width + x) * 3;
+            rgb[at] = 0;
+            rgb[at + 1] = 0;
+            rgb[at + 2] = 255;
+        }
+    }
+    rgb
+}
+
+/// Run audio through the decoder in blocks the size a sound card delivers.
+///
+/// A little silence is fed after the signal, as a receiver that keeps
+/// listening supplies: the demodulator is a filter, so the last millisecond of
+/// any transmission needs the samples after it before it can be read.
+fn decode(audio: &[f32]) -> (Vec<SstvImage>, usize) {
+    let mut tail = audio.to_vec();
+    tail.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize / 20));
+    let audio = tail.as_slice();
+
+    let mut decoder = SstvDecoder::new(SAMPLE_RATE, SstvConfig::default());
+    let mut images = Vec::new();
+    let mut rows = 0;
+    for block in audio.chunks(1024) {
+        for event in decoder.process_samples(block) {
+            match event {
+                SstvEvent::Row { .. } => rows += 1,
+                SstvEvent::Complete(image) => images.push(image),
+                SstvEvent::Started { .. } => {}
+            }
+        }
+    }
+    (images, rows)
+}
+
+/// Mean absolute error per colour channel between two same-sized images.
+fn mean_error(a: &[u8], b: &[u8]) -> f64 {
+    assert_eq!(a.len(), b.len());
+    let total: u64 = a
+        .iter()
+        .zip(b)
+        .map(|(x, y)| u64::from(x.abs_diff(*y)))
+        .sum();
+    total as f64 / a.len() as f64
+}
+
+/// Error over the part of the picture away from channel edges, where a decoder
+/// that is a pixel out on a hard colour boundary would otherwise dominate.
+fn interior_error(mode_width: usize, height: usize, sent: &[u8], got: &[u8]) -> f64 {
+    let mut total = 0u64;
+    let mut count = 0u64;
+    for y in 2..height.saturating_sub(2) {
+        for x in 4..mode_width.saturating_sub(4) {
+            // Skip the columns where the bars change, which is where a
+            // half-pixel timing difference shows up as a whole-colour error.
+            if x % (mode_width / 8) < 3 {
+                continue;
+            }
+            let at = (y * mode_width + x) * 3;
+            for channel in 0..3 {
+                total += u64::from(sent[at + channel].abs_diff(got[at + channel]));
+                count += 1;
+            }
+        }
+    }
+    total as f64 / count.max(1) as f64
+}
+
+fn round_trip(vis: u8, tolerance: f64) {
+    let mode = mode_for_vis(vis).expect("mode in table");
+    let width = usize::from(mode.width);
+    let height = usize::from(mode.height);
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let audio = encode(mode, &frame, SAMPLE_RATE);
+
+    let (images, rows) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        1,
+        "{}: expected one picture, got {}",
+        mode.name,
+        images.len()
+    );
+    let image = &images[0];
+    assert!(
+        image.complete,
+        "{}: reception did not reach the bottom",
+        mode.name
+    );
+    assert_eq!(image.mode, mode.name);
+    assert_eq!(
+        image.lines, mode.height,
+        "{}: {} of {} lines",
+        mode.name, image.lines, mode.height
+    );
+    assert_eq!(
+        rows, height,
+        "{}: emitted {rows} rows for {height} lines",
+        mode.name
+    );
+
+    let error = interior_error(width, height, &sent, &image.rgb);
+    assert!(
+        error < tolerance,
+        "{}: mean error {error:.1} levels, tolerance {tolerance:.1}",
+        mode.name,
+    );
+}
+
+#[test]
+fn martin_m1_round_trips() {
+    round_trip(44, 6.0);
+}
+
+#[test]
+fn martin_m2_round_trips() {
+    round_trip(40, 8.0);
+}
+
+#[test]
+fn scottie_s1_round_trips() {
+    round_trip(60, 6.0);
+}
+
+#[test]
+fn scottie_s2_round_trips() {
+    round_trip(56, 8.0);
+}
+
+#[test]
+fn wraase_sc2_180_round_trips() {
+    round_trip(55, 6.0);
+}
+
+// The colour-difference modes lose chroma resolution by design, so the bars
+// bleed into one another at their edges; the tolerance is on the interior.
+#[test]
+fn robot_72_round_trips() {
+    round_trip(12, 14.0);
+}
+
+#[test]
+fn robot_36_round_trips() {
+    // One chroma channel per line, the other carried over from the line
+    // before, so alternate lines are a line stale in one channel.
+    round_trip(8, 26.0);
+}
+
+#[test]
+fn pd90_round_trips() {
+    round_trip(99, 14.0);
+}
+
+#[test]
+fn pd120_round_trips() {
+    round_trip(95, 14.0);
+}
+
+/// Silence before and after is the normal case — a receiver is not started at
+/// the instant the transmission does.
+#[test]
+fn survives_silence_around_the_transmission() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let mut audio = vec![0.0f32; SAMPLE_RATE as usize * 2];
+    audio.extend(encode(mode, &frame, SAMPLE_RATE));
+    audio.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize));
+
+    let (images, _) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        1,
+        "expected one picture from a transmission in silence"
+    );
+    assert!(images[0].complete);
+}
+
+/// A transmission cut off part-way is what a fade or a shut-down transmitter
+/// produces. The lines that did arrive are worth keeping.
+#[test]
+fn a_truncated_transmission_still_yields_its_lines() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let full = encode(mode, &frame, SAMPLE_RATE);
+    // Two thirds of the picture, then silence for long enough that the decoder
+    // stops waiting for the rest.
+    let mut audio = full[..full.len() * 2 / 3].to_vec();
+    audio.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize * 5));
+
+    let (images, _) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        1,
+        "a cut-off transmission produced no picture"
+    );
+    let image = &images[0];
+    assert!(
+        !image.complete,
+        "a two-thirds transmission reported as complete"
+    );
+    assert!(
+        image.lines > mode.height / 2 && image.lines < mode.height,
+        "{} lines of {} arrived",
+        image.lines,
+        mode.height,
+    );
+    // What did arrive is the top of the picture, and it is right.
+    let rows = usize::from(image.lines).saturating_sub(4);
+    let error = mean_error(&sent[..width * rows * 3], &image.rgb[..width * rows * 3]);
+    assert!(
+        error < 12.0,
+        "the lines that arrived are wrong: mean error {error:.1}"
+    );
+}
+
+/// Two pictures back to back: the decoder has to finish the first and pick up
+/// the header of the second.
+#[test]
+fn decodes_a_second_transmission_after_the_first() {
+    let mode = mode_for_vis(40).expect("Martin M2");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let one = encode(mode, &frame, SAMPLE_RATE);
+
+    let mut audio = one.clone();
+    audio.extend(std::iter::repeat_n(0.0, SAMPLE_RATE as usize / 2));
+    audio.extend(one);
+
+    let (images, _) = decode(&audio);
+    assert_eq!(
+        images.len(),
+        2,
+        "expected two pictures, got {}",
+        images.len()
+    );
+    assert!(
+        images.iter().all(|image| image.complete),
+        "a picture did not finish"
+    );
+}
+
+/// Noise on the signal is the normal condition on HF. The picture should
+/// degrade, not fall apart.
+#[test]
+fn decodes_through_noise() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    let clean = encode(mode, &frame, SAMPLE_RATE);
+
+    // Deterministic pseudo-noise at about 20 dB below the signal.
+    let mut seed = 0x5eed_1234u32;
+    let noisy: Vec<f32> = clean
+        .iter()
+        .map(|sample| {
+            seed = seed.wrapping_mul(1_664_525).wrapping_add(1_013_904_223);
+            let noise = (seed >> 8) as f32 / f32::from(u16::MAX) / 256.0 - 0.5;
+            sample + noise * 0.2
+        })
+        .collect();
+
+    let (images, _) = decode(&noisy);
+    assert_eq!(images.len(), 1, "noise cost the whole picture");
+    let image = &images[0];
+    assert!(image.complete, "noise cost the bottom of the picture");
+    let error = interior_error(width, height, &sent, &image.rgb);
+    assert!(error < 20.0, "mean error through noise {error:.1} levels");
+}
+
+/// The sound card that plays the signal and the one that records it never
+/// agree exactly. A part-per-thousand error is far worse than reality and the
+/// picture should still stand up.
+#[test]
+fn tolerates_a_transmitter_clock_that_runs_fast() {
+    let mode = mode_for_vis(44).expect("Martin M1");
+    let (width, height) = (usize::from(mode.width), usize::from(mode.height));
+    let sent = test_card(width, height);
+    let frame = Frame {
+        width,
+        height,
+        rgb: &sent,
+    };
+    // Encoding at a slightly different rate and decoding at 48 kHz is exactly
+    // a clock error: every duration is stretched by the same factor.
+    let audio = encode(mode, &frame, 48_048);
+
+    let (images, _) = decode(&audio);
+    assert_eq!(images.len(), 1, "a 0.1% clock error cost the picture");
+    let error = interior_error(width, height, &sent, &images[0].rgb);
+    assert!(
+        error < 12.0,
+        "mean error with a fast clock {error:.1} levels"
+    );
+}

src/trx-app/Cargo.toml

@@ -9,9 +9,5 @@ edition = "2021"
 license = "GPL-2.0-or-later"
 
 [dependencies]
-serde = { workspace = true }
-toml = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
-dirs = "6"
-thiserror = "2"

src/trx-app/src/config.rs

@@ -1,88 +0,0 @@
-// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-use serde::de::DeserializeOwned;
-use std::path::{Path, PathBuf};
-use thiserror::Error;
-
-#[derive(Debug, Error)]
-pub enum ConfigError {
-    #[error("Failed to read config file {0}: {1}")]
-    ReadError(PathBuf, String),
-
-    #[error("Failed to parse config file {0}: {1}")]
-    ParseError(PathBuf, String),
-}
-
-/// Returns the default search paths for `trx-rs.toml`
-/// (current directory → XDG config → /etc).
-fn config_search_paths() -> Vec<PathBuf> {
-    let mut paths = vec![PathBuf::from("trx-rs.toml")];
-    if let Some(config_dir) = dirs::config_dir() {
-        paths.push(config_dir.join("trx-rs").join("trx-rs.toml"));
-    }
-    paths.push(PathBuf::from("/etc/trx-rs/trx-rs.toml"));
-    paths
-}
-
-/// Extract and deserialize a named section from a TOML file.
-///
-/// Returns `Ok(Some(cfg))` when the section is present and parses cleanly,
-/// `Ok(None)` when the section is absent, or `Err` on I/O / parse failure.
-fn load_section_from_file<T: DeserializeOwned>(
-    path: &Path,
-    key: &str,
-) -> Result<Option<T>, ConfigError> {
-    let content = std::fs::read_to_string(path)
-        .map_err(|e| ConfigError::ReadError(path.to_path_buf(), e.to_string()))?;
-
-    let table: toml::Table = toml::from_str(&content)
-        .map_err(|e| ConfigError::ParseError(path.to_path_buf(), e.to_string()))?;
-
-    let Some(section) = table.get(key) else {
-        return Ok(None);
-    };
-
-    // Re-serialize the section then parse as T so all serde defaults apply.
-    let section_toml = toml::to_string(section)
-        .map_err(|e| ConfigError::ParseError(path.to_path_buf(), e.to_string()))?;
-    let cfg = toml::from_str::<T>(&section_toml)
-        .map_err(|e| ConfigError::ParseError(path.to_path_buf(), e.to_string()))?;
-    Ok(Some(cfg))
-}
-
-/// Trait for loading configuration from a `trx-rs.toml` section.
-pub trait ConfigFile: Sized + Default + DeserializeOwned {
-    /// Section key in `trx-rs.toml` (e.g. `"trx-server"` or `"trx-client"`).
-    fn section_key() -> &'static str;
-
-    /// Load the section from a specific file path.
-    ///
-    /// Returns an error if the file cannot be read, is not valid TOML, or
-    /// does not contain the expected `[<section_key>]` header.
-    fn load_from_file(path: &Path) -> Result<Self, ConfigError> {
-        load_section_from_file::<Self>(path, Self::section_key())?.ok_or_else(|| {
-            ConfigError::ParseError(
-                path.to_path_buf(),
-                format!("missing [{}] section", Self::section_key()),
-            )
-        })
-    }
-
-    /// Search default paths (`trx-rs.toml` in CWD → XDG → /etc) and load
-    /// the first file that contains the expected section.
-    ///
-    /// Returns `(config, path_where_found)` or `(Default::default(), None)`
-    /// when no config file is found.
-    fn load_from_default_paths() -> Result<(Self, Option<PathBuf>), ConfigError> {
-        for path in config_search_paths() {
-            if path.exists() {
-                if let Some(cfg) = load_section_from_file::<Self>(&path, Self::section_key())? {
-                    return Ok((cfg, Some(path)));
-                }
-            }
-        }
-        Ok((Self::default(), None))
-    }
-}

src/trx-app/src/lib.rs

@@ -2,12 +2,12 @@
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-pub mod config;
+//! Shared application helpers.
+//!
+//! Configuration types and their loader live in the `trx-config` crate.
+
 pub mod logging;
-pub mod shared_config;
 pub mod util;
 
-pub use config::{ConfigError, ConfigFile};
 pub use logging::init_logging;
-pub use shared_config::{validate_log_level, validate_tokens};
 pub use util::normalize_name;

src/trx-client/Cargo.toml

@@ -21,6 +21,7 @@ uuid = { workspace = true }
 cpal = "0.15"
 opus = "0.3"
 trx-app = { path = "../trx-app" }
+trx-config = { path = "../trx-config" }
 trx-core = { path = "../trx-core" }
 trx-protocol = { path = "../trx-protocol" }
 trx-frontend = { path = "trx-frontend" }

src/trx-client/src/audio_client.rs

@@ -27,11 +27,11 @@ use trx_core::audio::{
     write_vchan_uuid_msg, AudioStreamInfo, AUDIO_MSG_AIS_DECODE, AUDIO_MSG_APRS_DECODE,
     AUDIO_MSG_CW_DECODE, AUDIO_MSG_FT2_DECODE, AUDIO_MSG_FT4_DECODE, AUDIO_MSG_FT8_DECODE,
     AUDIO_MSG_HF_APRS_DECODE, AUDIO_MSG_HISTORY_COMPRESSED, AUDIO_MSG_LRPT_IMAGE,
-    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_RX_FRAME_CH, AUDIO_MSG_STREAM_INFO,
-    AUDIO_MSG_TX_FRAME, AUDIO_MSG_VCHAN_ALLOCATED, AUDIO_MSG_VCHAN_BW, AUDIO_MSG_VCHAN_DESTROYED,
-    AUDIO_MSG_VCHAN_FREQ, AUDIO_MSG_VCHAN_MODE, AUDIO_MSG_VCHAN_REMOVE, AUDIO_MSG_VCHAN_SUB,
-    AUDIO_MSG_VCHAN_UNSUB, AUDIO_MSG_VDES_DECODE, AUDIO_MSG_WEFAX_DECODE, AUDIO_MSG_WEFAX_PROGRESS,
-    AUDIO_MSG_WSPR_DECODE,
+    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_RX_FRAME_CH, AUDIO_MSG_SSTV_DECODE,
+    AUDIO_MSG_SSTV_PROGRESS, AUDIO_MSG_STREAM_INFO, AUDIO_MSG_TX_FRAME, AUDIO_MSG_VCHAN_ALLOCATED,
+    AUDIO_MSG_VCHAN_BW, AUDIO_MSG_VCHAN_DESTROYED, AUDIO_MSG_VCHAN_FREQ, AUDIO_MSG_VCHAN_MODE,
+    AUDIO_MSG_VCHAN_REMOVE, AUDIO_MSG_VCHAN_SUB, AUDIO_MSG_VCHAN_UNSUB, AUDIO_MSG_VDES_DECODE,
+    AUDIO_MSG_WEFAX_DECODE, AUDIO_MSG_WEFAX_PROGRESS, AUDIO_MSG_WSPR_DECODE,
 };
 use trx_core::decode::DecodedMessage;
 use trx_frontend::VChanAudioCmd;
@@ -533,7 +533,9 @@ async fn handle_single_rig_connection(
                     | AUDIO_MSG_LRPT_IMAGE
                     | AUDIO_MSG_LRPT_PROGRESS
                     | AUDIO_MSG_WEFAX_DECODE
-                    | AUDIO_MSG_WEFAX_PROGRESS,
+                    | AUDIO_MSG_WEFAX_PROGRESS
+                    | AUDIO_MSG_SSTV_DECODE
+                    | AUDIO_MSG_SSTV_PROGRESS,
                     payload,
                 )) => {
                     if let Ok(mut msg) = serde_json::from_slice::<DecodedMessage>(&payload) {

src/trx-client/src/main.rs

@@ -20,6 +20,7 @@ use tokio::task::JoinHandle;
 use tracing::{error, info};
 
 use trx_app::{init_logging, normalize_name};
+use trx_config::ConfigFile;
 use trx_core::audio::AudioStreamInfo;
 
 use trx_core::decode::DecodedMessage;
@@ -50,6 +51,12 @@ struct Cli {
     /// Print example configuration and exit
     #[arg(long = "print-config")]
     print_config: bool,
+    /// Treat unknown configuration keys as a fatal error
+    #[arg(long = "strict-config")]
+    strict_config: bool,
+    /// Validate the configuration and exit without starting anything
+    #[arg(long = "check-config")]
+    check_config: bool,
     /// Remote server URL (host:port)
     #[arg(short = 'u', long = "url")]
     url: Option<String>,
@@ -74,7 +81,7 @@ struct Cli {
     /// rigctl frontend listen address
     #[arg(long = "rigctl-listen")]
     rigctl_listen: Option<IpAddr>,
-    /// rigctl frontend listen port
+    /// Deprecated: ignored, use [frontends.rigctl].rig_ports
     #[arg(long = "rigctl-port")]
     rigctl_port: Option<u16>,
     /// JSON TCP frontend listen address
@@ -109,6 +116,65 @@ async fn main() -> DynResult<()> {
     Ok(())
 }
 
+/// `--check-config`: report everything wrong with the configuration and exit.
+///
+/// Unlike startup, this reports every problem it finds rather than stopping at
+/// the first, so a config can be fixed in one pass.  The file is checked as
+/// written, without CLI overrides.
+fn check_config(loaded: &trx_config::ConfigLoad<ClientConfig>) -> DynResult<()> {
+    match &loaded.path {
+        Some(path) => println!("{}", path.display()),
+        None => println!("(no config file found; checking built-in defaults)"),
+    }
+
+    let mut warnings: Vec<String> = loaded.unknown_keys.iter().map(|k| k.to_string()).collect();
+    warnings.extend(ClientConfig::deprecations(&loaded.present_keys));
+
+    let mut cfg = loaded.config.clone();
+    let mut errors = Vec::new();
+    if let Err(e) = cfg.resolve_secrets(loaded.path.as_deref()) {
+        errors.push(e);
+    }
+    let cfg = &cfg;
+    let remotes = cfg.resolved_remotes();
+    if remotes.is_empty() {
+        warnings.push(
+            "no remotes configured; --url will be required at startup (add [[remotes]] entries)"
+                .to_string(),
+        );
+    }
+
+    errors.extend(cfg.validate_all());
+    if !remotes.is_empty() {
+        errors.extend(cfg.validate_resolved_all(&remotes));
+    }
+
+    for w in &warnings {
+        println!("  warning: {}", w);
+    }
+    for e in &errors {
+        println!("  error: {}", e);
+    }
+
+    if errors.is_empty() {
+        println!(
+            "  OK: {} remote(s) configured: {}",
+            remotes.len(),
+            remotes
+                .iter()
+                .map(|r| r.name.as_str())
+                .collect::<Vec<_>>()
+                .join(", ")
+        );
+        if !warnings.is_empty() {
+            println!("  {} warning(s)", warnings.len());
+        }
+        Ok(())
+    } else {
+        Err(format!("{} error(s), {} warning(s)", errors.len(), warnings.len()).into())
+    }
+}
+
 /// Holds the state needed after async initialization completes.
 struct AppState {
     shutdown_tx: watch::Sender<bool>,
@@ -135,20 +201,44 @@ async fn async_init() -> DynResult<AppState> {
         std::process::exit(0);
     }
 
-    let (cfg, config_path) = if let Some(ref path) = cli.config {
-        let cfg = ClientConfig::load_from_file(path)?;
-        (cfg, Some(path.clone()))
+    let loaded = if let Some(ref path) = cli.config {
+        ClientConfig::load_from_file(path)?
     } else {
         ClientConfig::load_from_default_paths()?
     };
-    cfg.validate()
-        .map_err(|e| format!("Invalid client configuration: {}", e))?;
+    let config_path = loaded.path.clone();
 
-    init_logging(cfg.general.log_level.as_deref());
+    if cli.check_config {
+        match check_config(&loaded) {
+            Ok(()) => std::process::exit(0),
+            Err(e) => {
+                eprintln!("{}", e);
+                std::process::exit(1);
+            }
+        }
+    }
+
+    // Logging comes up before any config complaint so the warnings are visible.
+    init_logging(loaded.config.general.log_level.as_deref());
 
     if let Some(ref path) = config_path {
         info!("Loaded configuration from {}", path.display());
     }
+    loaded.report_unknown_keys(cli.strict_config)?;
+    loaded.report_deprecations();
+    if cli.rigctl_port.is_some() {
+        tracing::warn!(
+            "--rigctl-port is ignored; give each rig its own listener via \
+             [frontends.rigctl].rig_ports"
+        );
+    }
+
+    let mut cfg = loaded.config;
+    // Secrets configured as *_file are read before validation, so everything
+    // downstream sees resolved values.
+    cfg.resolve_secrets(config_path.as_deref())?;
+    cfg.validate()
+        .map_err(|e| format!("Invalid client configuration: {}", e))?;
 
     frontend_runtime.http_auth.tokens = cfg
         .frontends
@@ -198,10 +288,14 @@ async fn async_init() -> DynResult<AppState> {
         let token = cli.token.clone().or_else(|| cfg.remote.auth.token.clone());
         let poll_interval_ms = cli.poll_interval_ms.unwrap_or(cfg.remote.poll_interval_ms);
         vec![RemoteEntry {
+            spectrum_interval_ms: cfg.remote.spectrum_interval_ms,
             name,
             url: url.clone(),
             rig_id,
-            auth: config::RemoteAuthConfig { token },
+            auth: config::RemoteAuthConfig {
+                token,
+                token_file: None,
+            },
             poll_interval_ms,
         }]
     } else {
@@ -262,6 +356,30 @@ async fn async_init() -> DynResult<AppState> {
         .http_json_listen
         .unwrap_or(cfg.frontends.http_json.listen);
     let http_json_port = cli.http_json_port.unwrap_or(cfg.frontends.http_json.port);
+
+    // Fold the CLI overrides back into the config so validation and the
+    // frontends agree on what is about to be bound.
+    cfg.frontends.http.enabled = frontends.iter().any(|f| f == "http");
+    cfg.frontends.rigctl.enabled = frontends.iter().any(|f| f == "rigctl");
+    cfg.frontends.http_json.enabled = frontends.iter().any(|f| f == "httpjson");
+    cfg.frontends.http.listen = http_listen;
+    cfg.frontends.http.port = http_port;
+    cfg.frontends.rigctl.listen = rigctl_listen;
+    cfg.frontends.http_json.listen = http_json_listen;
+    cfg.frontends.http_json.port = http_json_port;
+
+    // Second validation phase: the per-rig maps are keyed by remote short name,
+    // so they can only be checked once the remote list is final.
+    if cli.url.is_none() {
+        cfg.validate_resolved(&resolved_remotes)
+            .map_err(|e| format!("Invalid client configuration: {}", e))?;
+    } else {
+        // --url replaces the configured remotes outright, so only the socket
+        // checks still apply.
+        trx_config::shared::check_socket_conflicts(&cfg.bound_sockets())
+            .map_err(|e| format!("Invalid client configuration: {}", e))?;
+    }
+
     let callsign = cli
         .callsign
         .clone()
@@ -366,6 +484,13 @@ async fn async_init() -> DynResult<AppState> {
             .map(|e| e.poll_interval_ms)
             .min()
             .unwrap_or(750);
+        // Entries sharing a server share its connections, so the most frequent
+        // request wins: whoever wants spectrum fastest sets the rate.
+        let spectrum_interval = entries
+            .iter()
+            .map(|e| e.spectrum_interval_ms)
+            .min()
+            .unwrap_or_else(|| remote_client::DEFAULT_SPECTRUM_INTERVAL.as_millis() as u64);
 
         let (server_tx, server_rx) = mpsc::channel::<RigRequest>(RIG_TASK_CHANNEL_BUFFER);
         for entry in entries {
@@ -379,6 +504,8 @@ async fn async_init() -> DynResult<AppState> {
             known_rigs: frontend_runtime.routing.remote_rigs.clone(),
             rig_states: frontend_runtime.routing.rig_states.clone(),
             poll_interval: Duration::from_millis(poll_interval),
+            spectrum_interval: Duration::from_millis(spectrum_interval),
+            spectrum_stream_unsupported: Arc::new(std::sync::atomic::AtomicBool::new(false)),
             spectrum: frontend_runtime.spectrum.sender.clone(),
             rig_spectrums: frontend_runtime.spectrum.per_rig.clone(),
             server_connected: frontend_runtime.routing.server_connected.clone(),
@@ -527,6 +654,9 @@ async fn async_init() -> DynResult<AppState> {
                 DecodedMessage::LrptProgress(_) => {}
                 DecodedMessage::Wefax(_) => {}
                 DecodedMessage::WefaxProgress(_) => {}
+                // Pictures replay from their own history, not this one.
+                DecodedMessage::Sstv(_) => {}
+                DecodedMessage::SstvProgress(_) => {}
             }
         });
 

src/trx-client/src/remote_client.rs

@@ -20,35 +20,22 @@ use trx_core::{RigError, RigResult};
 use trx_frontend::{RemoteRigEntry, SharedSpectrum};
 use trx_protocol::rig_command_to_client;
 use trx_protocol::types::RigEntry;
-use trx_protocol::{ClientCommand, ClientEnvelope, ClientResponse, MeterUpdate};
+use trx_protocol::{ClientCommand, ClientEnvelope, ClientResponse, MeterUpdate, SpectrumFrame};
+
+// Endpoint parsing lives in `trx-config` so config validation and the
+// connection code agree on what a URL means.
+pub use trx_config::url::{parse_audio_url, parse_remote_url, RemoteEndpoint};
 
-const DEFAULT_REMOTE_PORT: u16 = 4530;
-const DEFAULT_AUDIO_PORT: u16 = 4531;
 const CONNECT_TIMEOUT: Duration = Duration::from_secs(5);
 const IO_TIMEOUT: Duration = Duration::from_secs(15);
 const SPECTRUM_IO_TIMEOUT: Duration = Duration::from_secs(3);
 const MAX_JSON_LINE_BYTES: usize = 256 * 1024;
 const MAX_CONSECUTIVE_POLL_FAILURES: u32 = 3;
 
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct RemoteEndpoint {
-    pub host: String,
-    pub port: u16,
-}
-
-impl RemoteEndpoint {
-    pub fn connect_addr(&self) -> String {
-        if self.host.contains(':') && !self.host.starts_with('[') {
-            format!("[{}]:{}", self.host, self.port)
-        } else {
-            format!("{}:{}", self.host, self.port)
-        }
-    }
-}
-
-// Keep remote spectrum reasonably responsive without returning to the old
-// timeout churn caused by a much tighter request cadence.
-const SPECTRUM_POLL_INTERVAL: Duration = Duration::from_millis(50);
+// Default spectrum cadence when a config does not specify one.  Both the push
+// stream and the poll fallback run at the configured rate; see
+// `[[remotes]].spectrum_interval_ms`.
+pub const DEFAULT_SPECTRUM_INTERVAL: Duration = Duration::from_millis(50);
 
 #[derive(Clone)]
 pub struct RemoteClientConfig {
@@ -57,6 +44,12 @@ pub struct RemoteClientConfig {
     pub selected_rig_id: Arc<Mutex<Option<String>>>,
     pub known_rigs: Arc<Mutex<Vec<RemoteRigEntry>>>,
     pub poll_interval: Duration,
+    /// How often spectrum frames are wanted.  Drives the poll fallback and is
+    /// the rate the client asks the server to push at.
+    pub spectrum_interval: Duration,
+    /// Set once a server has rejected `SubscribeSpectrum`, so later
+    /// connections to it go straight to polling instead of asking again.
+    pub spectrum_stream_unsupported: Arc<AtomicBool>,
     /// Spectrum watch sender; spectrum task publishes here, SSE clients subscribe.
     pub spectrum: Arc<watch::Sender<SharedSpectrum>>,
     /// Shared flag: `true` while a TCP connection to trx-server is active.
@@ -505,6 +498,100 @@ async fn send_get_sat_passes_on(
     ))
 }
 
+/// What ended a spectrum stream attempt.
+enum SpectrumStreamOutcome {
+    /// The stream ran and is over; the connection is spent.
+    Finished,
+    /// The server rejected the subscription.  The connection is still usable,
+    /// so the caller can poll on it.
+    Unsupported,
+}
+
+/// Subscribe to the server's spectrum push for one rig and publish frames as
+/// they arrive.
+///
+/// The server answers either with frames or, when it is too old to know the
+/// command, with an error response — which leaves the connection usable for
+/// polling, so falling back costs no reconnect.
+async fn run_spectrum_stream(
+    config: &RemoteClientConfig,
+    writer: &mut (impl AsyncWriteExt + Unpin),
+    reader: &mut (impl AsyncBufRead + Unpin),
+    short_name: &str,
+    shutdown_rx: &mut watch::Receiver<bool>,
+) -> RigResult<SpectrumStreamOutcome> {
+    let envelope = build_envelope(
+        config,
+        ClientCommand::SubscribeSpectrum,
+        Some(short_name.to_string()),
+    );
+    let mut payload = serde_json::to_string(&envelope)
+        .map_err(|e| RigError::communication(format!("JSON serialize failed: {e}")))?;
+    payload.push('\n');
+    time::timeout(SPECTRUM_IO_TIMEOUT, writer.write_all(payload.as_bytes()))
+        .await
+        .map_err(|_| RigError::communication("spectrum subscribe write timed out".to_string()))?
+        .map_err(|e| RigError::communication(format!("spectrum subscribe write failed: {e}")))?;
+    time::timeout(SPECTRUM_IO_TIMEOUT, writer.flush())
+        .await
+        .map_err(|_| RigError::communication("spectrum subscribe flush timed out".to_string()))?
+        .map_err(|e| RigError::communication(format!("spectrum subscribe flush failed: {e}")))?;
+
+    // Re-check what the UI wants: switching rigs has to end this stream so the
+    // connection can be rebuilt for the new one.
+    let mut supervisor = time::interval(Duration::from_millis(500));
+    supervisor.tick().await;
+
+    loop {
+        tokio::select! {
+            changed = shutdown_rx.changed() => {
+                match changed {
+                    Ok(()) if *shutdown_rx.borrow() => return Ok(SpectrumStreamOutcome::Finished),
+                    Ok(()) => {}
+                    Err(_) => return Ok(SpectrumStreamOutcome::Finished),
+                }
+            }
+            _ = supervisor.tick() => {
+                let wanted = active_spectrum_rig_ids(config);
+                if wanted.len() != 1 || wanted[0] != short_name {
+                    return Ok(SpectrumStreamOutcome::Finished);
+                }
+            }
+            line = read_limited_line(reader, MAX_JSON_LINE_BYTES) => {
+                let line = line
+                    .map_err(|e| RigError::communication(format!("spectrum read failed: {e}")))?
+                    .ok_or_else(|| {
+                        RigError::communication("spectrum connection closed".to_string())
+                    })?;
+                let trimmed = line.trim_end();
+                if trimmed.is_empty() {
+                    continue;
+                }
+                match serde_json::from_str::<SpectrumFrame>(trimmed) {
+                    Ok(frame) => publish_spectrum_frame(config, short_name, frame),
+                    // Anything that is not a frame means the server would rather
+                    // answer than stream: an older build rejecting the command.
+                    Err(_) => return Ok(SpectrumStreamOutcome::Unsupported),
+                }
+            }
+        }
+    }
+}
+
+/// Publish one pushed frame to the per-rig and selected-rig watch channels.
+fn publish_spectrum_frame(config: &RemoteClientConfig, short_name: &str, frame: SpectrumFrame) {
+    if let Ok(map) = config.rig_spectrums.read() {
+        if let Some(tx) = map.get(short_name) {
+            tx.send_modify(|s| s.set(Some(frame.spectrum.clone()), frame.vchan_rds.clone()));
+        }
+    }
+    if selected_rig_id(config).as_deref() == Some(short_name) {
+        config
+            .spectrum
+            .send_modify(|s| s.set(Some(frame.spectrum), frame.vchan_rds));
+    }
+}
+
 async fn handle_spectrum_connection(
     config: &RemoteClientConfig,
     stream: TcpStream,
@@ -512,7 +599,33 @@ async fn handle_spectrum_connection(
 ) -> RigResult<()> {
     let (reader, mut writer) = stream.into_split();
     let mut reader = BufReader::new(reader);
-    let mut interval = time::interval(SPECTRUM_POLL_INTERVAL);
+
+    // Prefer the push stream: polling costs a round trip per frame, so on a
+    // high-latency link the frame rate is 1/RTT no matter what interval is
+    // configured.  It only works for one rig per connection, and only against
+    // a server new enough to understand the command.
+    let streamable = active_spectrum_rig_ids(config);
+    if streamable.len() == 1 && !config.spectrum_stream_unsupported.load(Ordering::Relaxed) {
+        match run_spectrum_stream(
+            config,
+            &mut writer,
+            &mut reader,
+            &streamable[0],
+            shutdown_rx,
+        )
+        .await?
+        {
+            SpectrumStreamOutcome::Finished => return Ok(()),
+            SpectrumStreamOutcome::Unsupported => {
+                info!("Server does not support spectrum streaming; falling back to polling");
+                config
+                    .spectrum_stream_unsupported
+                    .store(true, Ordering::Relaxed);
+            }
+        }
+    }
+
+    let mut interval = time::interval(config.spectrum_interval);
     // Cache the token outside the poll loop to avoid cloning it every 50ms.
     let cached_token = config.token.clone();
 
@@ -1195,92 +1308,13 @@ async fn read_limited_line<R: AsyncBufRead + Unpin>(
     }
 }
 
-pub fn parse_remote_url(url: &str) -> Result<RemoteEndpoint, String> {
-    parse_endpoint_url(url, DEFAULT_REMOTE_PORT, "remote")
-}
-
-pub fn parse_audio_url(url: &str) -> Result<RemoteEndpoint, String> {
-    parse_endpoint_url(url, DEFAULT_AUDIO_PORT, "audio")
-}
-
-fn parse_endpoint_url(url: &str, default_port: u16, kind: &str) -> Result<RemoteEndpoint, String> {
-    let trimmed = url.trim();
-    if trimmed.is_empty() {
-        return Err(format!("{kind} url is empty"));
-    }
-
-    let addr = trimmed
-        .strip_prefix("tcp://")
-        .or_else(|| trimmed.strip_prefix("http-json://"))
-        .or_else(|| trimmed.strip_prefix("audio://"))
-        .unwrap_or(trimmed);
-
-    parse_host_port(addr, default_port, kind)
-}
-
-fn parse_host_port(input: &str, default_port: u16, kind: &str) -> Result<RemoteEndpoint, String> {
-    if let Some(rest) = input.strip_prefix('[') {
-        let closing = rest
-            .find(']')
-            .ok_or_else(|| format!("invalid {kind} url: missing closing ']' for IPv6 host"))?;
-        let host = &rest[..closing];
-        let remainder = &rest[closing + 1..];
-        if host.is_empty() {
-            return Err(format!("invalid {kind} url: host is empty"));
-        }
-        let port = if remainder.is_empty() {
-            default_port
-        } else if let Some(port_str) = remainder.strip_prefix(':') {
-            parse_port(port_str, kind)?
-        } else {
-            return Err(format!("invalid {kind} url: expected ':<port>' after ']'"));
-        };
-        return Ok(RemoteEndpoint {
-            host: host.to_string(),
-            port,
-        });
-    }
-
-    if input.contains(':') {
-        if input.matches(':').count() > 1 {
-            return Err(format!(
-                "invalid {kind} url: IPv6 host must be bracketed like [::1]:4532"
-            ));
-        }
-        let (host, port_str) = input
-            .rsplit_once(':')
-            .ok_or_else(|| format!("invalid {kind} url: expected host:port"))?;
-        if host.is_empty() {
-            return Err(format!("invalid {kind} url: host is empty"));
-        }
-        return Ok(RemoteEndpoint {
-            host: host.to_string(),
-            port: parse_port(port_str, kind)?,
-        });
-    }
-
-    Ok(RemoteEndpoint {
-        host: input.to_string(),
-        port: default_port,
-    })
-}
-
-fn parse_port(port_str: &str, kind: &str) -> Result<u16, String> {
-    let port: u16 = port_str
-        .parse()
-        .map_err(|_| format!("invalid {kind} port: '{port_str}'"))?;
-    if port == 0 {
-        return Err(format!("invalid {kind} port: 0"));
-    }
-    Ok(port)
-}
-
 #[cfg(test)]
 mod tests {
     #[allow(unused_imports)]
     use super::{has_short_names, resolve_server_rig_id, resolve_short_name};
     use super::{
         parse_audio_url, parse_remote_url, RemoteClientConfig, RemoteEndpoint, SharedSpectrum,
+        DEFAULT_SPECTRUM_INTERVAL,
     };
     use std::collections::HashMap;
     use std::sync::atomic::AtomicBool;
@@ -1475,6 +1509,8 @@ mod tests {
                 selected_rig_id: Arc::new(Mutex::new(None)),
                 known_rigs: Arc::new(Mutex::new(Vec::new())),
                 poll_interval: Duration::from_millis(100),
+                spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+                spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
                 spectrum: Arc::new(spectrum_tx),
                 server_connected: Arc::new(AtomicBool::new(false)),
                 rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
@@ -1520,6 +1556,8 @@ mod tests {
             selected_rig_id: Arc::new(Mutex::new(Some("sdr".to_string()))),
             known_rigs: Arc::new(Mutex::new(Vec::new())),
             poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
             spectrum: Arc::new(spectrum_tx),
             server_connected: Arc::new(AtomicBool::new(false)),
             rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
@@ -1535,6 +1573,130 @@ mod tests {
         assert_eq!(envelope.rig_id.as_deref(), Some("sdr"));
     }
 
+    fn stream_test_config(spectrum_tx: watch::Sender<SharedSpectrum>) -> super::RemoteClientConfig {
+        super::RemoteClientConfig {
+            addr: "127.0.0.1:4530".to_string(),
+            token: None,
+            selected_rig_id: Arc::new(Mutex::new(Some("sdr".to_string()))),
+            known_rigs: Arc::new(Mutex::new(Vec::new())),
+            poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
+            spectrum: Arc::new(spectrum_tx),
+            server_connected: Arc::new(AtomicBool::new(false)),
+            rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
+            rig_states: Arc::new(RwLock::new(HashMap::new())),
+            rig_spectrums: Arc::new(RwLock::new(HashMap::new())),
+            rig_id_to_short_name: HashMap::new(),
+            short_name_to_rig_id: Arc::new(RwLock::new(HashMap::new())),
+            sat_passes: Arc::new(RwLock::new(None)),
+            rig_meters: Arc::new(RwLock::new(HashMap::new())),
+        }
+    }
+
+    /// A pushed frame reaches the watch channel the UI reads, with no request
+    /// from the client beyond the initial subscribe.
+    #[tokio::test]
+    async fn spectrum_stream_publishes_pushed_frames() {
+        use tokio::io::{AsyncBufReadExt, BufReader};
+
+        let (spectrum_tx, mut spectrum_rx) = watch::channel(SharedSpectrum::default());
+        let config = stream_test_config(spectrum_tx);
+        let (shutdown_tx, mut shutdown_rx) = watch::channel(false);
+
+        let (client_io, mut server_io) = tokio::io::duplex(64 * 1024);
+        let (client_read, mut client_write) = tokio::io::split(client_io);
+        let mut client_read = BufReader::new(client_read);
+
+        let task = tokio::spawn(async move {
+            super::run_spectrum_stream(
+                &config,
+                &mut client_write,
+                &mut client_read,
+                "sdr",
+                &mut shutdown_rx,
+            )
+            .await
+        });
+
+        // The server sees the subscribe, then pushes without being asked.
+        let mut server = BufReader::new(&mut server_io);
+        let mut subscribe = String::new();
+        server.read_line(&mut subscribe).await.expect("subscribe");
+        assert!(
+            subscribe.contains("subscribe_spectrum"),
+            "unexpected command: {subscribe}"
+        );
+
+        let frame = trx_protocol::SpectrumFrame {
+            rig_id: "sdr".to_string(),
+            spectrum: trx_core::rig::state::SpectrumData {
+                bins: vec![-70.0, -30.0],
+                center_hz: 14_200_000,
+                sample_rate: 1_920_000,
+                rds: None,
+            },
+            vchan_rds: None,
+        };
+        let mut line = serde_json::to_string(&frame).unwrap();
+        line.push('\n');
+        server_io.write_all(line.as_bytes()).await.expect("push");
+        server_io.flush().await.expect("flush");
+
+        spectrum_rx.changed().await.expect("spectrum published");
+        let published = spectrum_rx.borrow().clone();
+        let spectrum = published.frame.expect("spectrum present");
+        assert_eq!(spectrum.center_hz, 14_200_000);
+        assert_eq!(spectrum.bins, vec![-70.0, -30.0]);
+
+        let _ = shutdown_tx.send(true);
+        let _ = task.await;
+    }
+
+    /// An older server answers the unknown command with an error instead of
+    /// frames.  That has to read as "poll instead", not as a dead connection.
+    #[tokio::test]
+    async fn spectrum_stream_falls_back_when_unsupported() {
+        use tokio::io::{AsyncBufReadExt, BufReader};
+
+        let (spectrum_tx, _spectrum_rx) = watch::channel(SharedSpectrum::default());
+        let config = stream_test_config(spectrum_tx);
+        let (_shutdown_tx, mut shutdown_rx) = watch::channel(false);
+
+        let (client_io, mut server_io) = tokio::io::duplex(64 * 1024);
+        let (client_read, mut client_write) = tokio::io::split(client_io);
+        let mut client_read = BufReader::new(client_read);
+
+        let task = tokio::spawn(async move {
+            super::run_spectrum_stream(
+                &config,
+                &mut client_write,
+                &mut client_read,
+                "sdr",
+                &mut shutdown_rx,
+            )
+            .await
+        });
+
+        let mut server = BufReader::new(&mut server_io);
+        let mut subscribe = String::new();
+        server.read_line(&mut subscribe).await.expect("subscribe");
+
+        server_io
+            .write_all(
+                b"{\"success\":false,\"state\":null,\"error\":\"Invalid JSON: unknown variant\"}\n",
+            )
+            .await
+            .expect("error response");
+        server_io.flush().await.expect("flush");
+
+        let outcome = task.await.expect("join").expect("stream result");
+        assert!(
+            matches!(outcome, super::SpectrumStreamOutcome::Unsupported),
+            "an error response should fall back to polling"
+        );
+    }
+
     #[test]
     fn build_envelope_translates_short_name_to_server_rig_id() {
         let (spectrum_tx, _spectrum_rx) = watch::channel(SharedSpectrum::default());
@@ -1548,6 +1710,8 @@ mod tests {
             selected_rig_id: Arc::new(Mutex::new(Some("home-hf".to_string()))),
             known_rigs: Arc::new(Mutex::new(Vec::new())),
             poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
             spectrum: Arc::new(spectrum_tx),
             server_connected: Arc::new(AtomicBool::new(false)),
             rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
@@ -1580,6 +1744,8 @@ mod tests {
             selected_rig_id: Arc::new(Mutex::new(None)),
             known_rigs: Arc::new(Mutex::new(Vec::new())),
             poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
             spectrum: Arc::new(spectrum_tx),
             server_connected: Arc::new(AtomicBool::new(false)),
             rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
@@ -1604,6 +1770,8 @@ mod tests {
             selected_rig_id: Arc::new(Mutex::new(None)),
             known_rigs: Arc::new(Mutex::new(Vec::new())),
             poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
             spectrum: Arc::new(spectrum_tx),
             server_connected: Arc::new(AtomicBool::new(false)),
             rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
@@ -1644,6 +1812,8 @@ mod tests {
             selected_rig_id: Arc::new(Mutex::new(None)),
             known_rigs: known_rigs.clone(),
             poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
             spectrum: Arc::new(spectrum_tx),
             server_connected: Arc::new(AtomicBool::new(false)),
             rig_server_connected: Arc::new(RwLock::new(HashMap::new())),
@@ -1717,6 +1887,8 @@ mod tests {
             selected_rig_id,
             known_rigs,
             poll_interval: Duration::from_millis(500),
+            spectrum_interval: DEFAULT_SPECTRUM_INTERVAL,
+            spectrum_stream_unsupported: Arc::new(AtomicBool::new(false)),
             spectrum: Arc::new(spectrum_tx),
             server_connected: Arc::new(AtomicBool::new(false)),
             rig_server_connected: Arc::new(RwLock::new(HashMap::new())),

src/trx-client/trx-frontend/src/lib.rs

@@ -17,8 +17,8 @@ use uuid::Uuid;
 
 use trx_core::audio::AudioStreamInfo;
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, VdesMessage, WefaxMessage,
-    WsprMessage,
+    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, SstvMessage, VdesMessage,
+    WefaxMessage, WsprMessage,
 };
 use trx_core::rig::state::{RigSnapshot, SpectrumData};
 use trx_core::{DynResult, RigRequest, RigState};
@@ -233,6 +233,7 @@ pub struct DecodeHistoryContext {
     pub ft2: DecodeHistory<Ft8Message>,
     pub wspr: DecodeHistory<WsprMessage>,
     pub wefax: DecodeHistory<WefaxMessage>,
+    pub sstv: DecodeHistory<SstvMessage>,
 }
 
 impl Default for DecodeHistoryContext {
@@ -248,6 +249,7 @@ impl Default for DecodeHistoryContext {
             ft2: Arc::new(Mutex::new(VecDeque::new())),
             wspr: Arc::new(Mutex::new(VecDeque::new())),
             wefax: Arc::new(Mutex::new(VecDeque::new())),
+            sstv: Arc::new(Mutex::new(VecDeque::new())),
         }
     }
 }

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js

@@ -747,7 +747,12 @@ function elementById(id) {
       api.applyLayout(savedLayoutName(), { persist: false });
     }
   }
-  const overflowOrder = [".operator-layout-picker", ".header-style-pick", "#theme-toggle"];
+  const overflowOrder = [
+    ".operator-layout-picker",
+    ".header-style-pick",
+    "#header-share-btn",
+    "#theme-toggle"
+  ];
   function anchorMenu(button, menu) {
     const rect = button.getBoundingClientRect();
     if (menu.parentElement !== document.body) document.body.appendChild(menu);
@@ -880,7 +885,7 @@ function elementById(id) {
       if (restoreFocus) more.focus();
     };
     api.closeMobileOverlays = closeMore;
-    ["statistics", "recorder", "settings", "about"].forEach((tabName) => {
+    ["satellites", "statistics", "recorder", "settings", "about"].forEach((tabName) => {
       const source = nav.querySelector(`[data-tab="${tabName}"]`);
       if (!source) return;
       const item = document.createElement("button");
@@ -927,7 +932,7 @@ function elementById(id) {
       ["Overview", ["overview"]],
       ["Marine & packet", ["ais", "vdes", "aprs", "hf-aprs"]],
       ["Weak signal", ["cw", "ft8", "ft4", "ft2", "wspr"]],
-      ["Broadcast & images", ["rds", "sat", "wefax"]]
+      ["Broadcast & images", ["rds", "sat", "wefax", "sstv"]]
     ];
     groups.forEach(([label, ids]) => {
       const group = document.createElement("optgroup");
@@ -1524,6 +1529,7 @@ var TAB_ORDER = [
   "bookmarks",
   "digital-modes",
   "map",
+  "satellites",
   "statistics",
   "recorder",
   "settings",
@@ -1534,6 +1540,7 @@ var TAB_PATHS = {
   bookmarks: "/bookmarks",
   "digital-modes": "/digital-modes",
   map: "/map",
+  satellites: "/satellites",
   statistics: "/statistics",
   recorder: "/recorder",
   settings: "/settings",
@@ -1555,6 +1562,44 @@ function updateTabHistory(name, replace = false) {
   if (replace) window.history.replaceState({}, "", nextUrl);
   else window.history.pushState({}, "", nextUrl);
 }
+var FREQ_MULTIPLIER = { k: 1e3, m: 1e6, g: 1e9 };
+function parseFrequencyParam(raw) {
+  if (typeof raw !== "string") return null;
+  const text = raw.trim().toLowerCase().replace(/hz$/, "").trim();
+  const match = /^(\d+(?:\.\d+)?)\s*([kmg]?)$/.exec(text);
+  if (!match) return null;
+  const value = Number(match[1]) * (FREQ_MULTIPLIER[match[2] ?? ""] ?? 1);
+  if (!Number.isFinite(value) || value <= 0) return null;
+  return Math.round(value);
+}
+function parseModeParam(raw) {
+  const mode = typeof raw === "string" ? raw.trim().toUpperCase() : "";
+  return /^[A-Z]{2,4}$/.test(mode) ? mode : null;
+}
+function parseTuneLink(search) {
+  const params = new URLSearchParams(search);
+  const rig = (params.get("rig") || "").trim();
+  return {
+    rig: rig || null,
+    freqHz: parseFrequencyParam(params.get("f")),
+    mode: parseModeParam(params.get("mode")),
+    bandwidthHz: parseFrequencyParam(params.get("bw"))
+  };
+}
+function tuneLinkSearch(search, link) {
+  const params = new URLSearchParams(search);
+  const set = (key, value) => {
+    if (value == null || value === "") params.delete(key);
+    else params.set(key, value);
+  };
+  const hz = (value) => typeof value === "number" && Number.isFinite(value) && value > 0 ? String(Math.round(value)) : null;
+  set("rig", link.rig);
+  set("f", hz(link.freqHz));
+  set("mode", parseModeParam(link.mode));
+  set("bw", hz(link.bandwidthHz));
+  const text = params.toString();
+  return text ? `?${text}` : "";
+}
 
 // src/features/radio/auto-bandwidth.ts
 function clampPercent(value) {
@@ -1705,6 +1750,7 @@ var pluginGroups = {
     "/background-decode.js",
     "/sat.js",
     "/wefax.js",
+    "/sstv.js",
     "/ais.js",
     "/vdes.js",
     "/aprs.js",
@@ -1712,6 +1758,7 @@ var pluginGroups = {
   ],
   "map-data": ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js"],
   map: ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js", "/sat.js", "/sat-scheduler.js"],
+  satellites: ["/satellite-predictions.js"],
   statistics: ["/map-core.js"],
   bookmarks: ["/bookmarks.js"],
   recorder: [],
@@ -1978,6 +2025,7 @@ function applyAuthRestrictions() {
 function applyCapabilities(caps) {
   if (!caps) return;
   lastHasTx = !!caps.tx;
+  bandwidthControlSupported = !!caps.filter_controls;
   if (signalVisualBlockEl) signalVisualBlockEl.style.display = "";
   const pttBtn2 = document.getElementById("ptt-btn");
   const txPowerCol = document.getElementById("tx-power-col");
@@ -2196,7 +2244,7 @@ function currentDecodeHistoryRetentionMs() {
 }
 window.getDecodeHistoryRetentionMs = currentDecodeHistoryRetentionMs;
 window.applyDecodeHistoryRetention = function() {
-  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax"]) {
+  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"]) {
     window.trxPluginRuntime.prune(decoder);
   }
 };
@@ -2325,6 +2373,7 @@ var jogAngle = 0;
 var lastClientCount = null;
 var lastLocked = false;
 var sdrSquelchSupported = false;
+var bandwidthControlSupported = false;
 var previousTuneState = null;
 function savePreviousTuneState() {
   previousTuneState = {
@@ -4410,6 +4459,85 @@ window.buildAisVesselUrl = function(mmsi) {
   if (!aisVesselUrlBase || !isFiniteNumber(Number(mmsi))) return null;
   return `${aisVesselUrlBase}${String(mmsi)}`;
 };
+var incomingTuneLink = parseTuneLink(window.location.search);
+var tuneLinkPhase = "pending";
+var tuneLinkSyncTimer = null;
+function currentTuneLink() {
+  const bandwidthHz = bandwidthControlSupported && isFiniteNumber(currentBandwidthHz) && currentBandwidthHz > 0 ? currentBandwidthHz : null;
+  return {
+    rig: lastActiveRigId || null,
+    freqHz: isFiniteNumber(lastFreqHz) ? lastFreqHz : null,
+    mode: lastModeName || null,
+    bandwidthHz
+  };
+}
+function tuneLinkUrl() {
+  const search = tuneLinkSearch(window.location.search, currentTuneLink());
+  return `${window.location.origin}${window.location.pathname}${search}${window.location.hash}`;
+}
+function scheduleTuneLinkSync() {
+  if (tuneLinkPhase !== "live") return;
+  if (window.trx?.modules.vchan?.isOnVirtual() === true) return;
+  if (tuneLinkSyncTimer != null) return;
+  tuneLinkSyncTimer = window.setTimeout(() => {
+    tuneLinkSyncTimer = null;
+    const search = tuneLinkSearch(window.location.search, currentTuneLink());
+    if (search === window.location.search) return;
+    window.history.replaceState({}, "", `${window.location.pathname}${search}${window.location.hash}`);
+  }, 500);
+}
+async function applyTuneLink(link) {
+  const wanted = link.rig || link.mode || link.freqHz != null || link.bandwidthHz != null;
+  if (!wanted) return;
+  if (authRole === "rx") {
+    showHint("Read-only session — link not applied", 2500);
+    return;
+  }
+  if (link.rig && headerRigSwitchSelect && link.rig !== lastActiveRigId && lastRigIds.includes(link.rig)) {
+    headerRigSwitchSelect.value = link.rig;
+    await switchRigFromSelect(headerRigSwitchSelect);
+  }
+  if (link.mode && link.mode !== lastModeName && modeEl) {
+    const known = Array.from(modeEl.options).some((option) => option.value === link.mode);
+    if (known) {
+      modeEl.value = link.mode;
+      await applyModeFromPicker();
+    } else {
+      showHint(`Rig has no ${link.mode} mode`, 2500);
+    }
+  }
+  if (link.freqHz != null) {
+    try {
+      setRigFrequency(link.freqHz);
+    } catch {
+    }
+  }
+  if (link.bandwidthHz != null && bandwidthControlSupported && spectrumBwInput) {
+    spectrumBwInput.value = String(link.bandwidthHz / 1e3);
+    await applyBandwidthFromInput();
+  }
+}
+function followTuneLinkOnce() {
+  if (tuneLinkPhase !== "pending") return;
+  tuneLinkPhase = "applying";
+  void applyTuneLink(incomingTuneLink).finally(() => {
+    tuneLinkPhase = "live";
+    scheduleTuneLinkSync();
+  });
+}
+async function copyTuneLink() {
+  const url = tuneLinkUrl();
+  try {
+    await navigator.clipboard.writeText(url);
+    showHint("Link copied", 1500);
+  } catch {
+    window.trxUi?.notify("Clipboard unavailable — the address bar holds the link", { kind: "error" });
+  }
+}
+var shareLinkBtn = document.getElementById("header-share-btn");
+if (shareLinkBtn) shareLinkBtn.addEventListener("click", () => {
+  void copyTuneLink();
+});
 function render(update) {
   if (!update) return;
   if (update.server_version) serverVersion = update.server_version;
@@ -4696,6 +4824,9 @@ function render(update) {
   for (const [key, entry] of Object.entries(_decoderToggles)) {
     syncDecoderToggle(entry, !!update[key], entry.label);
   }
+  if (typeof update.sstv_decode_enabled === "boolean" && window.syncSstvToggle) {
+    window.syncSstvToggle(update.sstv_decode_enabled);
+  }
   if (typeof update.wefax_decode_enabled === "boolean" && window.syncWefaxToggle) {
     window.syncWefaxToggle(update.wefax_decode_enabled);
   }
@@ -4922,6 +5053,8 @@ function render(update) {
     swrBar.style.width = "0%";
     swrValue.textContent = "SWR --";
   }
+  if (update.status) followTuneLinkOnce();
+  scheduleTuneLinkSync();
 }
 function scheduleReconnect(delayMs = 1e3) {
   if (reconnectTimer) return;
@@ -5714,6 +5847,7 @@ function _initMapWhenReady() {
 }
 function navigateToTab(name, options = {}) {
   window.trxUi?.closeMobileOverlays?.();
+  const leavingSatellites = _activeTab === "satellites" && name !== "satellites";
   const { updateHistory = true, replaceHistory = false } = options;
   if (authEnabled && !authRole && name !== "main") {
     showAuthGate(false);
@@ -5743,7 +5877,10 @@ function navigateToTab(name, options = {}) {
     updateTabHistory(name, replaceHistory);
   }
   scheduleSpectrumLayout();
-  void loadPluginsForTab(name).catch((error) => {
+  if (leavingSatellites) window.clearSatPredictionDom?.();
+  void loadPluginsForTab(name).then(() => {
+    if (name === "satellites") window.refreshSatPredictions?.();
+  }).catch((error) => {
     console.error(error);
   });
   if (name === "map") {
@@ -6190,9 +6327,6 @@ function _wireSubTabBar(bar) {
         if (window.refreshCwTonePicker) window.refreshCwTonePicker();
       });
     }
-    if (btn.dataset.subtab !== "sat" && typeof window.clearSatPredictionDom === "function") {
-      window.clearSatPredictionDom();
-    }
   });
 }
 document.querySelectorAll(".sub-tab-bar").forEach(_wireSubTabBar);
@@ -7468,9 +7602,17 @@ function updateDecodeStatus(text) {
     if (el && el.textContent !== "Receiving") el.textContent = text;
   }
 }
+var IMAGE_DECODE_KINDS = /* @__PURE__ */ new Set([
+  "lrpt_image",
+  "lrpt_progress",
+  "wefax",
+  "wefax_progress",
+  "sstv",
+  "sstv_progress"
+]);
 function dispatchDecodeMessage(msg, skipStats = false) {
   if (msg.type) window.trxPluginRuntime.dispatch(msg.type, msg);
-  if (!skipStats && msg.type && msg.type !== "lrpt_image" && msg.type !== "lrpt_progress" && msg.type !== "wefax" && msg.type !== "wefax_progress") {
+  if (!skipStats && msg.type && !IMAGE_DECODE_KINDS.has(msg.type)) {
     window.trx.modules.map?.statsRecordDecode(msg.type, msg.rig_id || msg.remote || null);
     window.trx.modules.map?.scheduleStatsRender();
   }
@@ -7516,7 +7658,7 @@ function loadDecodeHistoryOnMainThread(onReady, onError) {
 }
 function restoreDecodeHistoryGroup(kind, messages) {
   if (!Array.isArray(messages) || messages.length === 0) return;
-  if (kind !== "lrpt_image" && kind !== "lrpt_progress" && kind !== "wefax" && kind !== "wefax_progress") {
+  if (!IMAGE_DECODE_KINDS.has(kind)) {
     for (const msg of messages) {
       window.trx.modules.map?.statsRecordDecode(kind, msg.rig_id || msg.remote || null, msg.ts_ms || void 0);
     }

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/decode-history-worker.js

@@ -2,7 +2,7 @@
 (() => {
   // src/decode-history-worker.ts
   var textDecoder = typeof TextDecoder === "function" ? new TextDecoder() : null;
-  var HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax"];
+  var HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"];
   var workerScope = self;
   function decodeCborUint(view, bytes, state, additional) {
     const offset = state.offset;

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/sat.js

@@ -8,7 +8,6 @@ var satDom = {
   status: document.getElementById("sat-status"),
   liveView: document.getElementById("sat-live-view"),
   historyView: document.getElementById("sat-history-view"),
-  predictionsView: document.getElementById("sat-predictions-view"),
   liveLatest: document.getElementById("sat-live-latest"),
   historyList: document.getElementById("sat-history-list"),
   historyCount: document.getElementById("sat-history-count"),
@@ -17,29 +16,12 @@ var satDom = {
   typeFilter: document.getElementById("sat-type-filter"),
   lrptState: document.getElementById("sat-lrpt-state"),
   viewLiveBtn: document.getElementById("sat-view-live"),
-  viewHistoryBtn: document.getElementById("sat-view-history"),
-  viewPredBtn: document.getElementById("sat-view-predictions"),
-  predFilter: document.getElementById("sat-pred-filter"),
-  predMinEl: document.getElementById("sat-pred-min-el"),
-  predCategory: document.getElementById("sat-pred-category"),
-  predCurrentList: document.getElementById("sat-pred-current-list"),
-  predUpcomingList: document.getElementById("sat-pred-list"),
-  predCurrentSec: document.getElementById("sat-pred-current-section"),
-  predUpcomingSec: document.getElementById("sat-pred-upcoming-section"),
-  predStatus: document.getElementById("sat-pred-status")
+  viewHistoryBtn: document.getElementById("sat-view-history")
 };
 var satImageHistory = [];
 var SAT_MAX_IMAGES = 100;
-var SAT_PRED_PAGE_SIZE = 50;
-var satPredShowAll = false;
 var satFilterText = "";
 var satActiveView = "live";
-var satPredData = [];
-var satPredFilterText = "";
-var satPredMinEl = 0;
-var satPredCategory = "all";
-var satPredSatCount = 0;
-var satPredCountdownTimer = null;
 function scheduleSatUi(key, job) {
   if (typeof satWindow.trxScheduleUiFrameJob === "function") {
     satWindow.trxScheduleUiFrameJob(key, job);
@@ -48,37 +30,19 @@ function scheduleSatUi(key, job) {
   job();
 }
 function switchSatView(view) {
-  const leavingPredictions = satActiveView === "predictions" && view !== "predictions";
   satActiveView = view;
   if (satDom.liveView) satDom.liveView.style.display = view === "live" ? "" : "none";
   if (satDom.historyView) satDom.historyView.style.display = view === "history" ? "" : "none";
-  if (satDom.predictionsView) satDom.predictionsView.style.display = view === "predictions" ? "" : "none";
   if (satDom.viewLiveBtn) satDom.viewLiveBtn.classList.toggle("sat-view-active", view === "live");
   if (satDom.viewHistoryBtn) satDom.viewHistoryBtn.classList.toggle("sat-view-active", view === "history");
-  if (satDom.viewPredBtn) satDom.viewPredBtn.classList.toggle("sat-view-active", view === "predictions");
-  if (leavingPredictions) clearPredictionDom();
-  if (view === "history") {
-    renderSatHistoryTable();
-  } else if (view === "predictions") {
-    satPredShowAll = false;
-    void loadSatPredictions();
-  }
+  if (view === "history") renderSatHistoryTable();
 }
-function clearPredictionDom() {
-  stopCountdownTimer();
-  if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-}
-satWindow.clearSatPredictionDom = clearPredictionDom;
 satDom.viewLiveBtn?.addEventListener("click", () => {
   switchSatView("live");
 });
 satDom.viewHistoryBtn?.addEventListener("click", () => {
   switchSatView("history");
 });
-satDom.viewPredBtn?.addEventListener("click", () => {
-  switchSatView("predictions");
-});
 var lastSatLrptOn = null;
 satWindow.updateSatLiveState = function(update) {
   if (!satDom.lrptState) return;
@@ -275,200 +239,6 @@ document.getElementById("settings-clear-sat-history")?.addEventListener("click",
     }
   })();
 });
-function azToCardinal(deg) {
-  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
-  return dirs[Math.round(deg / 45) % 8] ?? "N";
-}
-function formatPredTime(ms) {
-  const d = new Date(ms);
-  const now = /* @__PURE__ */ new Date();
-  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
-  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
-  const hh = String(d.getUTCHours()).padStart(2, "0");
-  const mm = String(d.getUTCMinutes()).padStart(2, "0");
-  return `${day}${hh}:${mm}`;
-}
-function formatPredDuration(s) {
-  if (s >= 60) return `${Math.round(s / 60)} min`;
-  return `${s}s`;
-}
-function formatCountdown(ms) {
-  const totalSec = Math.max(0, Math.floor(ms / 1e3));
-  const m = Math.floor(totalSec / 60);
-  const s = totalSec % 60;
-  return `${m}:${String(s).padStart(2, "0")}`;
-}
-function elevationClass(deg) {
-  if (deg >= 45) return "sat-pred-el-high";
-  if (deg >= 10) return "sat-pred-el-mid";
-  return "sat-pred-el-low";
-}
-function stopCountdownTimer() {
-  if (satPredCountdownTimer) {
-    clearInterval(satPredCountdownTimer);
-    satPredCountdownTimer = null;
-  }
-}
-function startCountdownTimer(container) {
-  const countdownEls = container?.querySelectorAll(".sat-pred-col-countdown") ?? [];
-  if (countdownEls.length === 0) return;
-  satPredCountdownTimer = setInterval(() => {
-    if (satActiveView !== "predictions") {
-      stopCountdownTimer();
-      return;
-    }
-    const n = Date.now();
-    let anyActive = false;
-    for (const el of countdownEls) {
-      const los = Number.parseInt(el.dataset.los ?? "0", 10);
-      const rem = los - n;
-      if (rem > 0) {
-        el.textContent = formatCountdown(rem);
-        anyActive = true;
-      } else {
-        el.textContent = "0:00";
-      }
-    }
-    if (!anyActive) {
-      stopCountdownTimer();
-      renderSatPredictions(getFilteredPredictions());
-    }
-  }, 1e3);
-}
-function buildCurrentPassRow(pass, now) {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row-current";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
-  const remaining = Math.max(0, pass.los_ms - now);
-  row.innerHTML = [
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
-    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`
-  ].join("");
-  return row;
-}
-function buildUpcomingPassRow(pass) {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
-  row.innerHTML = [
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
-    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`
-  ].join("");
-  return row;
-}
-function getFilteredPredictions() {
-  let items = satPredData;
-  if (satPredCategory !== "all") items = items.filter((p) => p.category === satPredCategory);
-  if (satPredMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= satPredMinEl);
-  if (satPredFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(satPredFilterText));
-  return items;
-}
-function applyPredFilters() {
-  renderSatPredictions(getFilteredPredictions());
-}
-var satPredictionFilter = satDom.predFilter;
-satPredictionFilter?.addEventListener("input", () => {
-  satPredFilterText = satPredictionFilter.value.trim().toUpperCase();
-  applyPredFilters();
-});
-var satPredictionMinElevation = satDom.predMinEl;
-satPredictionMinElevation?.addEventListener("change", () => {
-  satPredMinEl = Number.parseInt(satPredictionMinElevation.value, 10) || 0;
-  applyPredFilters();
-});
-var satPredictionCategory = satDom.predCategory;
-satPredictionCategory?.addEventListener("change", () => {
-  satPredCategory = satPredictionCategory.value;
-  applyPredFilters();
-});
-function renderSatPredictions(passes, error) {
-  stopCountdownTimer();
-  if (error) {
-    if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus) satDom.predStatus.textContent = error;
-    return;
-  }
-  if (!Array.isArray(passes) || passes.length === 0) {
-    if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus) satDom.predStatus.textContent = "No passes found in the next 24 hours.";
-    return;
-  }
-  const now = Date.now();
-  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
-  const upcoming = passes.filter((p) => p.aos_ms > now);
-  if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = current.length > 0 ? "" : "none";
-  if (satDom.predCurrentList) {
-    if (current.length === 0) {
-      satDom.predCurrentList.innerHTML = "";
-    } else {
-      const frag = document.createDocumentFragment();
-      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
-      satDom.predCurrentList.replaceChildren(frag);
-    }
-  }
-  const upcomingLimit = satPredShowAll ? upcoming.length : SAT_PRED_PAGE_SIZE;
-  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
-  const hiddenCount = upcoming.length - visibleUpcoming.length;
-  if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = upcoming.length > 0 ? "" : "none";
-  if (satDom.predUpcomingList) {
-    const frag = document.createDocumentFragment();
-    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
-    if (hiddenCount > 0) {
-      const moreRow = document.createElement("div");
-      moreRow.className = "sat-pred-row";
-      moreRow.style.cursor = "pointer";
-      moreRow.style.textAlign = "center";
-      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes…</span>`;
-      moreRow.addEventListener("click", () => {
-        satPredShowAll = true;
-        renderSatPredictions(getFilteredPredictions());
-      });
-      frag.appendChild(moreRow);
-    }
-    satDom.predUpcomingList.replaceChildren(frag);
-  }
-  if (satDom.predStatus) {
-    let text = `${current.length} active · ${upcoming.length} upcoming · times in UTC`;
-    if (satPredSatCount > 0) text += ` · ${satPredSatCount} satellites tracked`;
-    satDom.predStatus.textContent = text;
-  }
-  if (current.length > 0 && satActiveView === "predictions") {
-    startCountdownTimer(satDom.predCurrentList);
-  }
-}
-async function loadSatPredictions() {
-  if (satDom.predStatus) satDom.predStatus.textContent = "Loading predictions…";
-  if (satDom.predCurrentList) satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-  try {
-    const resp = await fetch("/sat_passes");
-    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
-    const data = await resp.json();
-    satPredSatCount = data.satellite_count || 0;
-    if (data.error) {
-      satPredData = [];
-      renderSatPredictions([], data.error);
-    } else {
-      satPredData = data.passes || [];
-      renderSatPredictions(getFilteredPredictions());
-    }
-  } catch (error) {
-    renderSatPredictions([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
-  }
-}
 satWindow.satShowOnMap = function(south, west, north, east) {
   if (typeof satWindow.enableMapSourceFilter === "function") {
     satWindow.enableMapSourceFilter("sat");

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/satellite-predictions.js

@@ -0,0 +1,228 @@
+// src/plugins/satellite-predictions.ts
+var predWindow = window;
+var dom = {
+  page: document.getElementById("tab-satellites"),
+  filter: document.getElementById("sat-pred-filter"),
+  minElevation: document.getElementById("sat-pred-min-el"),
+  category: document.getElementById("sat-pred-category"),
+  currentList: document.getElementById("sat-pred-current-list"),
+  upcomingList: document.getElementById("sat-pred-list"),
+  currentSection: document.getElementById("sat-pred-current-section"),
+  upcomingSection: document.getElementById("sat-pred-upcoming-section"),
+  status: document.getElementById("sat-pred-status")
+};
+var PAGE_SIZE = 50;
+var predShowAll = false;
+var predData = [];
+var predFilterText = "";
+var predMinEl = 0;
+var predCategory = "all";
+var predSatCount = 0;
+var predCountdownTimer = null;
+function isPageVisible() {
+  return !!dom.page && dom.page.style.display !== "none";
+}
+function azToCardinal(deg) {
+  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
+  return dirs[Math.round(deg / 45) % 8] ?? "N";
+}
+function formatPredTime(ms) {
+  const d = new Date(ms);
+  const now = /* @__PURE__ */ new Date();
+  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
+  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
+  const hh = String(d.getUTCHours()).padStart(2, "0");
+  const mm = String(d.getUTCMinutes()).padStart(2, "0");
+  return `${day}${hh}:${mm}`;
+}
+function formatPredDuration(s) {
+  if (s >= 60) return `${Math.round(s / 60)} min`;
+  return `${s}s`;
+}
+function formatCountdown(ms) {
+  const totalSec = Math.max(0, Math.floor(ms / 1e3));
+  const m = Math.floor(totalSec / 60);
+  const s = totalSec % 60;
+  return `${m}:${String(s).padStart(2, "0")}`;
+}
+function elevationClass(deg) {
+  if (deg >= 45) return "sat-pred-el-high";
+  if (deg >= 10) return "sat-pred-el-mid";
+  return "sat-pred-el-low";
+}
+function stopCountdownTimer() {
+  if (predCountdownTimer) {
+    clearInterval(predCountdownTimer);
+    predCountdownTimer = null;
+  }
+}
+function startCountdownTimer(container) {
+  const countdownEls = container?.querySelectorAll(".sat-pred-col-countdown") ?? [];
+  if (countdownEls.length === 0) return;
+  predCountdownTimer = setInterval(() => {
+    if (!isPageVisible()) {
+      stopCountdownTimer();
+      return;
+    }
+    const n = Date.now();
+    let anyActive = false;
+    for (const el of countdownEls) {
+      const los = Number.parseInt(el.dataset.los ?? "0", 10);
+      const rem = los - n;
+      if (rem > 0) {
+        el.textContent = formatCountdown(rem);
+        anyActive = true;
+      } else {
+        el.textContent = "0:00";
+      }
+    }
+    if (!anyActive) {
+      stopCountdownTimer();
+      render(filtered());
+    }
+  }, 1e3);
+}
+function buildCurrentPassRow(pass, now) {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row-current";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
+  const remaining = Math.max(0, pass.los_ms - now);
+  row.innerHTML = [
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
+    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`
+  ].join("");
+  return row;
+}
+function buildUpcomingPassRow(pass) {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} → ${azToCardinal(pass.azimuth_los_deg)}`;
+  row.innerHTML = [
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}°</span>`,
+    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`
+  ].join("");
+  return row;
+}
+function filtered() {
+  let items = predData;
+  if (predCategory !== "all") items = items.filter((p) => p.category === predCategory);
+  if (predMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= predMinEl);
+  if (predFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(predFilterText));
+  return items;
+}
+function applyFilters() {
+  render(filtered());
+}
+var filterInput = dom.filter;
+filterInput?.addEventListener("input", () => {
+  predFilterText = filterInput.value.trim().toUpperCase();
+  applyFilters();
+});
+var minElevationSelect = dom.minElevation;
+minElevationSelect?.addEventListener("change", () => {
+  predMinEl = Number.parseInt(minElevationSelect.value, 10) || 0;
+  applyFilters();
+});
+var categorySelect = dom.category;
+categorySelect?.addEventListener("change", () => {
+  predCategory = categorySelect.value;
+  applyFilters();
+});
+function render(passes, error) {
+  stopCountdownTimer();
+  if (error) {
+    if (dom.currentList) dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection) dom.currentSection.style.display = "none";
+    if (dom.upcomingSection) dom.upcomingSection.style.display = "none";
+    if (dom.status) dom.status.textContent = error;
+    return;
+  }
+  if (!Array.isArray(passes) || passes.length === 0) {
+    if (dom.currentList) dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection) dom.currentSection.style.display = "none";
+    if (dom.upcomingSection) dom.upcomingSection.style.display = "none";
+    if (dom.status) dom.status.textContent = "No passes found in the next 24 hours.";
+    return;
+  }
+  const now = Date.now();
+  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
+  const upcoming = passes.filter((p) => p.aos_ms > now);
+  if (dom.currentSection) dom.currentSection.style.display = current.length > 0 ? "" : "none";
+  if (dom.currentList) {
+    if (current.length === 0) {
+      dom.currentList.innerHTML = "";
+    } else {
+      const frag = document.createDocumentFragment();
+      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
+      dom.currentList.replaceChildren(frag);
+    }
+  }
+  const upcomingLimit = predShowAll ? upcoming.length : PAGE_SIZE;
+  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
+  const hiddenCount = upcoming.length - visibleUpcoming.length;
+  if (dom.upcomingSection) dom.upcomingSection.style.display = upcoming.length > 0 ? "" : "none";
+  if (dom.upcomingList) {
+    const frag = document.createDocumentFragment();
+    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
+    if (hiddenCount > 0) {
+      const moreRow = document.createElement("div");
+      moreRow.className = "sat-pred-row";
+      moreRow.style.cursor = "pointer";
+      moreRow.style.textAlign = "center";
+      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes…</span>`;
+      moreRow.addEventListener("click", () => {
+        predShowAll = true;
+        render(filtered());
+      });
+      frag.appendChild(moreRow);
+    }
+    dom.upcomingList.replaceChildren(frag);
+  }
+  if (dom.status) {
+    let text = `${current.length} active · ${upcoming.length} upcoming · times in UTC`;
+    if (predSatCount > 0) text += ` · ${predSatCount} satellites tracked`;
+    dom.status.textContent = text;
+  }
+  if (current.length > 0 && isPageVisible()) {
+    startCountdownTimer(dom.currentList);
+  }
+}
+async function load() {
+  if (dom.status) dom.status.textContent = "Loading predictions…";
+  if (dom.currentList) dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+  try {
+    const resp = await fetch("/sat_passes");
+    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
+    const data = await resp.json();
+    predSatCount = data.satellite_count || 0;
+    if (data.error) {
+      predData = [];
+      render([], data.error);
+    } else {
+      predData = data.passes || [];
+      render(filtered());
+    }
+  } catch (error) {
+    render([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
+  }
+}
+function clearPredictionDom() {
+  stopCountdownTimer();
+  if (dom.currentList) dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+}
+predWindow.clearSatPredictionDom = clearPredictionDom;
+predWindow.refreshSatPredictions = function() {
+  predShowAll = false;
+  void load();
+};

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/sstv.js

@@ -0,0 +1,249 @@
+import {
+  hostCore
+} from "./chunk-KL66PICH.js";
+
+// src/plugins/sstv.ts
+var sstvWindow = window;
+var sstvDom = {
+  status: document.getElementById("sstv-status"),
+  liveView: document.getElementById("sstv-live-view"),
+  historyView: document.getElementById("sstv-history-view"),
+  liveContainer: document.getElementById("sstv-live-container"),
+  liveInfo: document.getElementById("sstv-live-info"),
+  liveCanvas: document.getElementById("sstv-live-canvas"),
+  liveLatest: document.getElementById("sstv-live-latest"),
+  historyList: document.getElementById("sstv-history-list"),
+  historyCount: document.getElementById("sstv-history-count"),
+  filterInput: document.getElementById("sstv-filter"),
+  sortSelect: document.getElementById("sstv-sort"),
+  toggleBtn: document.getElementById("sstv-decode-toggle-btn"),
+  clearBtn: document.getElementById("sstv-clear-btn"),
+  viewLiveBtn: document.getElementById("sstv-view-live"),
+  viewHistoryBtn: document.getElementById("sstv-view-history")
+};
+var SSTV_MAX_IMAGES = 100;
+var sstvHistory = [];
+var liveCtx = null;
+var liveMode = "";
+var liveHeight = 0;
+var liveRows = 0;
+var activeView = "live";
+var filterText = "";
+function retentionMs() {
+  return sstvWindow.getDecodeHistoryRetentionMs?.() ?? 24 * 60 * 60 * 1e3;
+}
+function pruneHistory() {
+  const cutoff = Date.now() - retentionMs();
+  sstvHistory = sstvHistory.filter((image) => (image._tsMs || 0) > cutoff);
+}
+function escapeHtml(value) {
+  return String(value).replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;");
+}
+function scheduleUi(key, job) {
+  if (typeof sstvWindow.trxScheduleUiFrameJob === "function") {
+    sstvWindow.trxScheduleUiFrameJob(key, job);
+    return;
+  }
+  job();
+}
+function imageUrl(image) {
+  if (!image.path) return null;
+  const filename = image.path.split(/[\\/]/).pop();
+  return filename ? `/sstv-images/${encodeURIComponent(filename)}` : null;
+}
+function decodeBase64(data) {
+  const binary = atob(data);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i += 1) bytes[i] = binary.charCodeAt(i);
+  return bytes;
+}
+function switchView(view) {
+  activeView = view;
+  if (sstvDom.liveView) sstvDom.liveView.style.display = view === "live" ? "" : "none";
+  if (sstvDom.historyView) sstvDom.historyView.style.display = view === "history" ? "" : "none";
+  for (const button of [sstvDom.viewLiveBtn, sstvDom.viewHistoryBtn]) {
+    button?.classList.remove("sat-view-active");
+  }
+  if (view === "live") sstvDom.viewLiveBtn?.classList.add("sat-view-active");
+  else sstvDom.viewHistoryBtn?.classList.add("sat-view-active");
+  if (view === "history") renderHistoryTable();
+}
+sstvDom.viewLiveBtn?.addEventListener("click", () => {
+  switchView("live");
+});
+sstvDom.viewHistoryBtn?.addEventListener("click", () => {
+  switchView("history");
+});
+function beginPicture(mode, width, height) {
+  const canvas = sstvDom.liveCanvas;
+  if (!canvas || width <= 0 || height <= 0) return;
+  liveMode = mode;
+  liveHeight = height;
+  liveRows = 0;
+  canvas.width = width;
+  canvas.height = height;
+  liveCtx = canvas.getContext("2d");
+  if (!liveCtx) return;
+  liveCtx.fillStyle = "#606060";
+  liveCtx.fillRect(0, 0, width, height);
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "";
+  updateLiveInfo();
+}
+function updateLiveInfo() {
+  if (!sstvDom.liveInfo) return;
+  const canvas = sstvDom.liveCanvas;
+  const size = canvas ? `${canvas.width}×${canvas.height}` : "";
+  sstvDom.liveInfo.textContent = liveMode ? `${liveMode} · ${size} · line ${liveRows}${liveHeight ? ` of ${liveHeight}` : ""}` : "";
+}
+function paintRow(line, rgb) {
+  const canvas = sstvDom.liveCanvas;
+  if (!liveCtx || !canvas) return;
+  const width = canvas.width;
+  if (line < 0 || line >= canvas.height || rgb.length < width * 3) return;
+  const row = liveCtx.createImageData(width, 1);
+  for (let x = 0; x < width; x += 1) {
+    row.data[x * 4] = rgb[x * 3] ?? 0;
+    row.data[x * 4 + 1] = rgb[x * 3 + 1] ?? 0;
+    row.data[x * 4 + 2] = rgb[x * 3 + 2] ?? 0;
+    row.data[x * 4 + 3] = 255;
+  }
+  liveCtx.putImageData(row, 0, line);
+  liveRows = Math.max(liveRows, line + 1);
+}
+function onProgress(msg) {
+  if (msg.state) {
+    if (sstvDom.status) sstvDom.status.textContent = msg.state;
+    beginPicture(msg.mode || "", msg.width || 0, msg.height || 0);
+    return;
+  }
+  if (typeof msg.line !== "number" || !msg.line_data) return;
+  const line = msg.line;
+  const rgb = decodeBase64(msg.line_data);
+  scheduleUi(`sstv-row-${line}`, () => {
+    paintRow(line, rgb);
+    updateLiveInfo();
+  });
+}
+function onImage(msg) {
+  const image = { ...msg };
+  image._tsMs = typeof msg.ts_ms === "number" ? msg.ts_ms : Date.now();
+  image._ts = new Date(image._tsMs).toLocaleTimeString();
+  sstvHistory.push(image);
+  if (sstvHistory.length > SSTV_MAX_IMAGES) sstvHistory.shift();
+  pruneHistory();
+  if (sstvDom.status) {
+    sstvDom.status.textContent = image.complete ? `Received ${image.mode ?? "picture"}` : `Partial ${image.mode ?? "picture"} — ${image.lines ?? 0} lines`;
+  }
+  scheduleUi("sstv-latest", renderLatestCard);
+  if (activeView === "history") scheduleUi("sstv-history", renderHistoryTable);
+}
+function renderLatestCard() {
+  if (!sstvDom.liveLatest) return;
+  const latest = sstvHistory[sstvHistory.length - 1];
+  if (!latest) {
+    sstvDom.liveLatest.innerHTML = "";
+    return;
+  }
+  const url = imageUrl(latest);
+  const lines = `${latest.lines ?? 0}${latest.height ? ` of ${latest.height}` : ""} lines`;
+  const state = latest.complete ? "complete" : "partial";
+  sstvDom.liveLatest.innerHTML = `
+    <div class="sat-latest-card">
+      <div style="display:flex; align-items:baseline; gap:0.5rem; flex-wrap:wrap;">
+        <strong>${escapeHtml(latest.mode ?? "SSTV")}</strong>
+        <small style="color:var(--text-muted);">${escapeHtml(latest._ts ?? "")} · ${lines} · ${state}</small>
+      </div>
+      ${url ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">
+             <img src="${escapeHtml(url)}" alt="Received ${escapeHtml(latest.mode ?? "SSTV")} picture"
+                  style="margin-top:0.4rem; width:100%; max-width:640px; image-rendering:pixelated;" />
+           </a>` : ""}
+    </div>`;
+}
+function filteredHistory() {
+  const text = filterText.trim().toLowerCase();
+  const matching = text ? sstvHistory.filter((image) => (image.mode ?? "").toLowerCase().includes(text)) : sstvHistory.slice();
+  const newestFirst = (sstvDom.sortSelect?.value ?? "newest") === "newest";
+  matching.sort((a, b) => (newestFirst ? 1 : -1) * ((b._tsMs ?? 0) - (a._tsMs ?? 0)));
+  return matching;
+}
+function renderHistoryTable() {
+  if (!sstvDom.historyList) return;
+  pruneHistory();
+  const rows = filteredHistory();
+  sstvDom.historyList.innerHTML = rows.map((image) => {
+    const url = imageUrl(image);
+    const size = image.width && image.height ? `${image.width}×${image.height}` : "--";
+    const lines = image.complete ? String(image.lines ?? 0) : `${image.lines ?? 0} (partial)`;
+    return `<div class="sat-history-row">
+        <span class="sat-col-time">${escapeHtml(image._ts ?? "")}</span>
+        <span class="sat-col-type">${escapeHtml(image.mode ?? "--")}</span>
+        <span class="sat-col-sat">${escapeHtml(size)}</span>
+        <span class="sat-col-lines">${escapeHtml(lines)}</span>
+        <span class="sat-col-link">${url ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">View</a>` : "--"}</span>
+      </div>`;
+  }).join("");
+  if (sstvDom.historyCount) {
+    sstvDom.historyCount.textContent = rows.length ? `${rows.length} picture${rows.length === 1 ? "" : "s"}` : "No pictures yet";
+  }
+}
+sstvDom.filterInput?.addEventListener("input", () => {
+  filterText = sstvDom.filterInput?.value ?? "";
+  renderHistoryTable();
+});
+sstvDom.sortSelect?.addEventListener("change", () => {
+  renderHistoryTable();
+});
+function restoreHistory(entries) {
+  if (!Array.isArray(entries)) return;
+  for (const entry of entries) onImage(entry);
+}
+function resetHistoryView() {
+  sstvHistory = [];
+  liveRows = 0;
+  liveMode = "";
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "none";
+  if (sstvDom.status) sstvDom.status.textContent = "Idle";
+  renderLatestCard();
+  renderHistoryTable();
+}
+sstvWindow.syncSstvToggle = function syncSstvToggle(enabled) {
+  const button = sstvDom.toggleBtn;
+  if (!button) return;
+  button.textContent = enabled ? "Disable SSTV" : "Enable SSTV";
+  button.setAttribute("aria-pressed", String(enabled));
+  button.classList.toggle("is-active", enabled);
+};
+sstvDom.toggleBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      if (sstvDom.toggleBtn) {
+        await sstvWindow.takeSchedulerControlForDecoderDisable?.(sstvDom.toggleBtn);
+      }
+      await hostCore.postPath("/toggle_sstv_decode");
+    } catch (e) {
+      console.error("SSTV toggle failed", e);
+    }
+  })();
+});
+sstvDom.clearBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      await hostCore.postPath("/clear_sstv_decode");
+      resetHistoryView();
+    } catch (e) {
+      console.error("SSTV clear failed", e);
+    }
+  })();
+});
+renderLatestCard();
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv",
+  onMessage: onImage,
+  restore: restoreHistory,
+  prune: renderHistoryTable,
+  reset: resetHistoryView
+});
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv_progress",
+  onMessage: onProgress
+});

src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html

@@ -24,6 +24,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
     <symbol id="icon-bookmark" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M4 2h8v12l-4-2.5L4 14V2z"/></symbol>
     <symbol id="icon-digital" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M1 11.5h2.6V4.5h3.2v7h3.2v-7h3.2v7H15"/></symbol>
     <symbol id="icon-map" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M8 2a4 4 0 0 1 4 4c0 3-4 8-4 8S4 9 4 6a4 4 0 0 1 4-4z"/><circle cx="8" cy="6" r="1.2" fill="currentColor" stroke="none"/></symbol>
+    <symbol id="icon-satellite" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M2 13.2 5.6 9.6"/><path d="M4.2 8.2a3.4 3.4 0 0 1 4.8 4.8z"/><path d="M9.2 6.6a3.2 3.2 0 0 1 2.6 2.6"/><path d="M9.8 3.6a6.2 6.2 0 0 1 5.2 5.2"/></symbol>
     <symbol id="icon-stats" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M2 14h12"/><rect x="3" y="8" width="2" height="6" rx="0.4" fill="currentColor" stroke="none" opacity="0.6"/><rect x="7" y="5" width="2" height="9" rx="0.4" fill="currentColor" stroke="none" opacity="0.75"/><rect x="11" y="2" width="2" height="12" rx="0.4" fill="currentColor" stroke="none" opacity="0.9"/></symbol>
     <symbol id="icon-record" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><circle cx="8" cy="8" r="6"/><circle cx="8" cy="8" r="2.5" fill="currentColor" stroke="none"/></symbol>
     <symbol id="icon-settings" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M9.8 3.1a2.6 2.6 0 0 0-2.2 3.9L3.4 11.2a1.2 1.2 0 1 0 1.7 1.7l4.2-4.2a2.6 2.6 0 0 0 3.9-2.2l-1.8.6-1.2-1.2z"/><path d="M10.2 5.8 12 4"/></symbol>
@@ -52,14 +53,21 @@ SPDX-License-Identifier: GPL-2.0-or-later
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-bookmark"/></svg>
             <span class="tab-label">Bookmarks</span>
           </button>
-          <button class="tab" data-tab="digital-modes">
+          <button class="tab" data-tab="digital-modes" aria-label="Digital modes">
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-digital"/></svg>
             <span class="tab-label">Digital modes</span>
+            <!-- A fifth of a phone screen does not hold "Digital modes"; the
+                 button keeps the full name for assistive tech. -->
+            <span class="tab-label-short" aria-hidden="true">Digital</span>
           </button>
           <button class="tab" data-tab="map">
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-map"/></svg>
             <span class="tab-label">Map</span>
           </button>
+          <button class="tab" data-tab="satellites">
+            <svg class="tab-icon" aria-hidden="true"><use href="#icon-satellite"/></svg>
+            <span class="tab-label">Satellites</span>
+          </button>
           <button class="tab" data-tab="statistics">
             <svg class="tab-icon" aria-hidden="true"><use href="#icon-stats"/></svg>
             <span class="tab-label">Statistics</span>
@@ -99,6 +107,9 @@ SPDX-License-Identifier: GPL-2.0-or-later
             <option value="phosphor">Phosphor</option>
           </select>
         </div>
+        <button id="header-share-btn" class="header-bar-btn header-share-btn" type="button" aria-label="Copy a link to this frequency" title="Copy a link to this frequency">
+          <svg viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.6" stroke-linecap="round" aria-hidden="true"><path d="M6.5 9.5a2.6 2.6 0 0 0 3.9.3l2.2-2.2a2.6 2.6 0 0 0-3.7-3.7l-1 1"/><path d="M9.5 6.5a2.6 2.6 0 0 0-3.9-.3L3.4 8.4a2.6 2.6 0 0 0 3.7 3.7l1-1"/></svg>
+        </button>
         <button id="theme-toggle" class="header-bar-btn" type="button" aria-label="Toggle dark or light theme">Light</button>
         <button id="header-auth-btn" class="header-bar-btn" type="button" style="display:none;" aria-label="Login or Logout">Login</button>
       </div>
@@ -160,13 +171,14 @@ SPDX-License-Identifier: GPL-2.0-or-later
         <div id="spectrum-size-grip" title="Drag to resize spectrum height" aria-label="Resize spectrum height"></div>
         <div id="spectrum-controls">
           <div id="spectrum-bw-row">
-            <label id="spectrum-bw-label">Bandwidth <input type="number" id="spectrum-bw-input" value="" step="0.1" min="0.1" /> kHz</label>
-            <button id="spectrum-bw-set-btn" type="button">Set</button>
-            <button id="spectrum-bw-auto-btn" type="button">Auto BW</button>
-            <button id="spectrum-bw-sweet-btn" type="button">Sweet-spot</button>
+            <label id="spectrum-bw-label" class="spectrum-field"><span class="spectrum-field-name">Bandwidth</span><input type="number" id="spectrum-bw-input" value="" step="0.1" min="0.1" /><span class="spectrum-field-unit">kHz</span></label>
+            <button id="spectrum-bw-set-btn" class="spectrum-btn" type="button">Set</button>
+            <button id="spectrum-bw-auto-btn" class="spectrum-btn" type="button">Auto BW</button>
+            <button id="spectrum-bw-sweet-btn" class="spectrum-btn" type="button">Sweet-spot</button>
           </div>
+          <div class="spectrum-controls-spacer" aria-hidden="true"></div>
           <div id="spectrum-level-row">
-            <label class="overview-control" id="spectrum-peak-hold-label">Peak Hold
+            <label class="overview-control spectrum-field" id="spectrum-peak-hold-label"><span class="spectrum-field-name">Peak Hold</span>
               <select id="overview-peak-hold" class="status-input">
                 <option value="0">Off</option>
                 <option value="500">0.5 s</option>
@@ -179,10 +191,10 @@ SPDX-License-Identifier: GPL-2.0-or-later
                 <option value="60000">60 s</option>
               </select>
             </label>
-            <label id="spectrum-floor-label">Floor <input type="number" id="spectrum-floor-input" value="-115" step="5" /> dB</label>
-            <label id="spectrum-range-label">Range <input type="number" id="spectrum-range-input" value="90" step="10" min="10" /> dB</label>
-            <button id="spectrum-auto-btn" type="button">Auto</button>
-            <label id="spectrum-gamma-label">Contrast <input type="range" id="spectrum-gamma-input" min="0.2" max="3.0" step="0.1" value="1.0" /><span id="spectrum-gamma-value">1.0</span></label>
+            <label id="spectrum-floor-label" class="spectrum-field"><span class="spectrum-field-name">Floor</span><input type="number" id="spectrum-floor-input" value="-115" step="5" /><span class="spectrum-field-unit">dB</span></label>
+            <label id="spectrum-range-label" class="spectrum-field"><span class="spectrum-field-name">Range</span><input type="number" id="spectrum-range-input" value="90" step="10" min="10" /><span class="spectrum-field-unit">dB</span></label>
+            <button id="spectrum-auto-btn" class="spectrum-btn" type="button">Auto</button>
+            <label id="spectrum-gamma-label" class="spectrum-field"><span class="spectrum-field-name">Contrast</span><input type="range" id="spectrum-gamma-input" min="0.2" max="3.0" step="0.1" value="1.0" /><span id="spectrum-gamma-value" class="spectrum-field-value">1.0</span></label>
           </div>
         </div>
         <div id="spectrum-hint" class="spectrum-hint-mouse">Scroll to zoom &middot; Ctrl+Scroll to tune &middot; Drag to pan &middot; Drag BW edges to resize &middot; +/- zoom &middot; Arrows pan &middot; 0 reset</div>
@@ -581,6 +593,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
         <button class="sub-tab" data-subtab="rds">RDS</button>
         <button class="sub-tab" data-subtab="sat">SAT</button>
         <button class="sub-tab" data-subtab="wefax">WEFAX</button>
+        <button class="sub-tab" data-subtab="sstv">SSTV</button>
       </div>
       <div id="subtab-overview" class="sub-tab-panel">
         <div class="plugin-item" data-decoder="ais">
@@ -643,6 +656,12 @@ SPDX-License-Identifier: GPL-2.0-or-later
             Decodes Meteor-M LRPT (137 MHz QPSK) weather satellite imagery.
           </div>
         </div>
+        <div class="plugin-item" data-decoder="sstv">
+          <strong>SSTV Decoder</strong>
+          <div style="color:var(--text-muted); font-size:0.85rem; margin-top:0.2rem;">
+            Slow-Scan Television &mdash; pictures in Martin, Scottie, Robot, PD and Wraase modes
+          </div>
+        </div>
         <div class="plugin-item" data-decoder="wefax">
           <strong>WEFAX Decoder</strong>
           <div style="color:var(--text-muted); font-size:0.85rem; margin-top:0.2rem;">
@@ -650,6 +669,56 @@ SPDX-License-Identifier: GPL-2.0-or-later
           </div>
         </div>
       </div>
+      <div id="subtab-sstv" class="sub-tab-panel" style="display:none;">
+        <div class="ft8-controls">
+          <button id="sstv-decode-toggle-btn" type="button">Enable SSTV</button>
+          <small id="sstv-status" style="color:var(--text-muted);">Idle</small>
+        </div>
+        <!-- View selector -->
+        <div class="sat-view-bar">
+          <button id="sstv-view-live" class="sat-view-btn sat-view-active" type="button">Live</button>
+          <button id="sstv-view-history" class="sat-view-btn" type="button">History</button>
+        </div>
+        <!-- Live view -->
+        <div id="sstv-live-view">
+          <div style="margin:0 0 0.5rem;">
+            <div style="color:var(--text-muted); font-size:0.82rem; line-height:1.5;">
+              <strong>Slow-Scan Television</strong> &mdash; pictures sent as tones, in Martin,
+              Scottie, Robot, PD and Wraase modes. Tune a sideband or FM signal and enable the
+              decoder; the mode is read from the header the sender opens with.
+            </div>
+          </div>
+          <div id="sstv-live-container" style="display:none; margin:0.5rem 0;">
+            <div style="display:flex; align-items:center; gap:0.5rem; margin-bottom:0.3rem;">
+              <strong>Receiving</strong>
+              <small id="sstv-live-info" style="color:var(--text-muted);"></small>
+            </div>
+            <canvas id="sstv-live-canvas" width="320" height="256"
+                    style="width:100%; max-width:640px; image-rendering:pixelated; background:#111;"></canvas>
+          </div>
+          <div id="sstv-live-latest" style="margin-top:0.5rem;"></div>
+        </div>
+        <!-- History view -->
+        <div id="sstv-history-view" style="display:none;">
+          <div class="sat-history-controls">
+            <input id="sstv-filter" class="ft8-filter" type="text" placeholder="Filter (e.g. Martin, PD120)" />
+            <select id="sstv-sort" class="sat-sort-select">
+              <option value="newest">Newest first</option>
+              <option value="oldest">Oldest first</option>
+            </select>
+            <button id="sstv-clear-btn" type="button" style="font-size:0.8rem;">Clear All</button>
+          </div>
+          <div class="sat-history-header">
+            <span class="sat-col-time">Time</span>
+            <span class="sat-col-type">Mode</span>
+            <span class="sat-col-sat">Size</span>
+            <span class="sat-col-lines">Lines</span>
+            <span class="sat-col-link">Image</span>
+          </div>
+          <div id="sstv-history-list"></div>
+          <small id="sstv-history-count" style="color:var(--text-muted);font-size:0.75rem;">No pictures yet</small>
+        </div>
+      </div>
       <div id="subtab-rds" class="sub-tab-panel" style="display:none;">
         <div class="rds-grid">
           <div class="rds-field"><span class="rds-label">Status</span><span id="rds-status" class="rds-value rds-no-signal">No signal</span></div>
@@ -854,7 +923,6 @@ SPDX-License-Identifier: GPL-2.0-or-later
         <div class="sat-view-bar">
           <button id="sat-view-live" class="sat-view-btn sat-view-active" type="button">Live</button>
           <button id="sat-view-history" class="sat-view-btn" type="button">History</button>
-          <button id="sat-view-predictions" class="sat-view-btn" type="button">Predictions</button>
         </div>
         <!-- Live view -->
         <div id="sat-live-view">
@@ -896,50 +964,6 @@ SPDX-License-Identifier: GPL-2.0-or-later
           <div id="sat-history-list"></div>
           <small id="sat-history-count" style="color:var(--text-muted);font-size:0.75rem;">No images yet</small>
         </div>
-        <!-- Predictions view -->
-        <div id="sat-predictions-view" style="display:none;">
-          <div class="ft8-controls">
-            <input id="sat-pred-filter" class="ft8-filter" type="text" placeholder="Filter (e.g. ISS, NOAA, Meteor)" />
-            <select id="sat-pred-category" class="sat-sort-select">
-              <option value="all">All</option>
-              <option value="weather">Weather</option>
-              <option value="amateur">Ham Radio</option>
-              <option value="other">Other</option>
-            </select>
-            <select id="sat-pred-min-el" class="sat-sort-select">
-              <option value="0">All passes</option>
-              <option value="10">Min 10°</option>
-              <option value="20">Min 20°</option>
-              <option value="45">Min 45°</option>
-            </select>
-          </div>
-          <!-- Current passes -->
-          <div id="sat-pred-current-section">
-            <div class="sat-pred-section-title">Currently receivable</div>
-            <div class="sat-pred-header sat-pred-header-current">
-              <span class="sat-pred-col-sat">Satellite</span>
-              <span class="sat-pred-col-el">Max El</span>
-              <span class="sat-pred-col-time">AOS Start</span>
-              <span class="sat-pred-col-time">AOS End</span>
-              <span class="sat-pred-col-countdown">Time left</span>
-              <span class="sat-pred-col-dir">Direction</span>
-            </div>
-            <div id="sat-pred-current-list"></div>
-          </div>
-          <!-- Upcoming passes -->
-          <div id="sat-pred-upcoming-section">
-            <div class="sat-pred-section-title">Upcoming passes</div>
-            <div class="sat-pred-header">
-              <span class="sat-pred-col-time">AOS (UTC)</span>
-              <span class="sat-pred-col-sat">Satellite</span>
-              <span class="sat-pred-col-el">Max El</span>
-              <span class="sat-pred-col-dur">Duration</span>
-              <span class="sat-pred-col-dir">Direction</span>
-            </div>
-            <div id="sat-pred-list"></div>
-          </div>
-          <small id="sat-pred-status" style="color:var(--text-muted);font-size:0.75rem;">Loading predictions&hellip;</small>
-        </div>
       </div>
       <div id="subtab-wefax" class="sub-tab-panel" style="display:none;">
         <div class="ft8-controls">
@@ -1053,6 +1077,51 @@ SPDX-License-Identifier: GPL-2.0-or-later
       </div>
       </template>
     </div>
+    <div id="tab-satellites" class="tab-panel" style="display:none;">
+      <h2 class="section-heading">Satellites</h2>
+      <div class="ft8-controls">
+        <input id="sat-pred-filter" class="ft8-filter" type="text" placeholder="Filter (e.g. ISS, NOAA, Meteor)" />
+        <select id="sat-pred-category" class="sat-sort-select">
+          <option value="all">All</option>
+          <option value="weather">Weather</option>
+          <option value="amateur">Ham Radio</option>
+          <option value="other">Other</option>
+        </select>
+        <select id="sat-pred-min-el" class="sat-sort-select">
+          <option value="0">All passes</option>
+          <option value="10">Min 10°</option>
+          <option value="20">Min 20°</option>
+          <option value="45">Min 45°</option>
+        </select>
+      </div>
+      <!-- Current passes -->
+      <div id="sat-pred-current-section">
+        <div class="sat-pred-section-title">Currently receivable</div>
+        <div class="sat-pred-header sat-pred-header-current">
+          <span class="sat-pred-col-sat">Satellite</span>
+          <span class="sat-pred-col-el">Max El</span>
+          <span class="sat-pred-col-time">AOS Start</span>
+          <span class="sat-pred-col-time">AOS End</span>
+          <span class="sat-pred-col-countdown">Time left</span>
+          <span class="sat-pred-col-dir">Direction</span>
+        </div>
+        <div id="sat-pred-current-list"></div>
+      </div>
+      <!-- Upcoming passes -->
+      <div id="sat-pred-upcoming-section">
+        <div class="sat-pred-section-title">Upcoming passes</div>
+        <div class="sat-pred-header">
+          <span class="sat-pred-col-time">AOS (UTC)</span>
+          <span class="sat-pred-col-sat">Satellite</span>
+          <span class="sat-pred-col-el">Max El</span>
+          <span class="sat-pred-col-dur">Duration</span>
+          <span class="sat-pred-col-dir">Direction</span>
+        </div>
+        <div id="sat-pred-list"></div>
+      </div>
+      <small id="sat-pred-status" style="color:var(--text-muted);font-size:0.75rem;">Loading predictions&hellip;</small>
+    </div>
+
     <div id="tab-statistics" class="tab-panel" style="display:none;">
       <h2 class="section-heading">Statistics</h2>
       <template id="tmpl-statistics">

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -1345,7 +1345,10 @@ small { color: var(--text-muted); }
 .top-bar-actions > * {
   flex: 0 0 auto;
 }
-.header-bar-btn.header-audio-btn {
+/* Square icon buttons in the top bar: an icon with no box of its own has no
+   size to draw at, so the button gives it one. */
+.header-bar-btn.header-audio-btn,
+.header-bar-btn.header-share-btn {
   width: 2rem;
   height: 2rem;
   min-height: 0;
@@ -1360,10 +1363,15 @@ small { color: var(--text-muted); }
   cursor: pointer;
   flex-shrink: 0;
 }
-.header-audio-btn svg {
+.header-audio-btn svg,
+.header-share-btn svg {
   width: 100%;
   height: 100%;
 }
+/* The link icon is drawn in strokes, not fills, and wants room around it. */
+.header-share-btn svg {
+  padding: 1px;
+}
 .header-audio-btn.audio-active {
   color: #00d17f;
   border-color: #00d17f;
@@ -1709,6 +1717,8 @@ small { color: var(--text-muted); }
   flex-shrink: 0;
 }
 .tab-label { display: block; }
+/* Only the bottom nav is short of room. */
+.tab-label-short { display: none; }
 .tab-more-icon { display: none; }
 .about-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 1rem; }
 .about-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 0.5rem; padding: 0; overflow: hidden; }
@@ -2584,7 +2594,6 @@ button.map-qso-card:focus-visible {
   box-shadow: 0 16px 30px rgba(0, 0, 0, 0.24);
   backdrop-filter: blur(6px);
   -webkit-backdrop-filter: blur(6px);
-  will-change: backdrop-filter;
   overflow: auto;
   transition: opacity 140ms ease, transform 140ms ease, visibility 140ms ease;
 }
@@ -2602,9 +2611,15 @@ button.map-qso-card:focus-visible {
 .map-overlay-filters.is-hidden {
   display: none;
 }
-/* With the filters collapsed the bar has no reason to span the map. */
+/* With the filters collapsed the bar has no reason to span the map.
+   It keeps both anchors and shrinks inside them, rather than dropping `left`
+   and being sized by shrink-to-fit: the anchored box is a size the browser
+   already knows, and an absolutely positioned, backdrop-filtered, composited
+   box being asked to size itself from its content is the shape of thing that
+   renders as nothing on engines other than the one it was written against. */
 .map-overlay-panel.filters-hidden {
-  left: auto;
+  width: fit-content;
+  margin-left: auto;
 }
 .map-overlay-actions {
   display: flex;
@@ -2731,7 +2746,6 @@ button.map-qso-card:focus-visible {
   box-shadow: 0 16px 30px rgba(0, 0, 0, 0.2);
   backdrop-filter: blur(6px);
   -webkit-backdrop-filter: blur(6px);
-  will-change: backdrop-filter;
   overflow: auto;
 }
 .map-band-legend.is-empty {
@@ -3802,11 +3816,12 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
 @media (max-width: 760px) {
   body[data-operator-layout="broadcast"] #wfm-controls-col { flex-basis: 100%; }
 }
-/* One navigation model at every width.  Statistics, Recorder, Settings and
- * About are occasional destinations: they live behind More rather than
- * competing with the operating tabs for the row and then scrolling out of
+/* One navigation model at every width.  Satellites, Statistics, Recorder,
+ * Settings and About are occasional destinations: they live behind More rather
+ * than competing with the operating tabs for the row and then scrolling out of
  * reach.  The mobile layout already grouped them this way; the desktop strip
  * now matches it, which is why the tab strip no longer needs to scroll. */
+.tab-bar-nav .tab[data-tab="satellites"],
 .tab-bar-nav .tab[data-tab="statistics"],
 .tab-bar-nav .tab[data-tab="recorder"],
 .tab-bar-nav .tab[data-tab="settings"],
@@ -3884,7 +3899,18 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   input.status-input, select.status-input { font-size: 1.1rem; }
   :root { --header-waterfall-overlap: 0rem; }
   .controls-tray-scroll { overflow-x: auto; }
-  .controls-tray { width: 100%; min-width: 0; padding-left: 0.85rem; padding-right: 0.85rem; }
+  /* A grid column sizes to its content by default, so one row wider than the
+     phone — the mode picker, six buttons across — dragged the whole tray out
+     with it and left the rest to be found by scrolling sideways. `minmax(0,
+     1fr)` lets the column be as narrow as the screen and the rows wrap inside
+     it. */
+  .controls-tray {
+    width: 100%;
+    min-width: 0;
+    grid-template-columns: minmax(0, 1fr);
+    padding-left: 0.85rem;
+    padding-right: 0.85rem;
+  }
   .freq-inline { gap: 0.5rem; flex-wrap: wrap; }
   .header-text { width: auto; min-width: 0; flex: 0 1 auto; }
   .header-main {
@@ -4005,12 +4031,9 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     box-shadow: inset 0 1px 0 color-mix(in srgb, #ffffff 8%, transparent);
   }
   .tab-icon, .tab-more-icon { display: block; }
-  /* Shorten long tab labels to keep bottom nav compact */
-  .tab[data-tab="bookmarks"] .tab-label { font-size: 0.6rem; }
-  .tab[data-tab="digital-modes"] .tab-label  { font-size: 0.6rem; }
-  .tab[data-tab="statistics"] .tab-label { font-size: 0.6rem; }
-  .tab[data-tab="statistics"], .tab[data-tab="recorder"],
-  .tab[data-tab="settings"], .tab[data-tab="about"] { display: none; }
+  .tab[data-tab="satellites"], .tab[data-tab="statistics"],
+  .tab[data-tab="recorder"], .tab[data-tab="settings"],
+  .tab[data-tab="about"] { display: none; }
   .mobile-more-btn { display: flex; }
   .mobile-more-menu {
     position: fixed;
@@ -4022,7 +4045,48 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     color: var(--accent-text);
     background: color-mix(in srgb, var(--accent-green) 10%, transparent);
   }
-  .tab .tab-label, .tab[data-tab] .tab-label { font-size: 0.75rem; }
+  /* The bottom nav divides the bar between its five destinations, so a tab is
+     about a fifth of the screen and the label has to live inside that. Sharing
+     the width evenly beats sizing each tab to its own label, which gave
+     "Digital modes" the same room as "Map" and clipped it mid-word. */
+  .tab-bar-nav .tab {
+    flex: 1 1 0;
+    min-width: 0;
+    padding-left: 0.15rem;
+    padding-right: 0.15rem;
+  }
+  .tab .tab-label, .tab[data-tab] .tab-label {
+    display: block;
+    max-width: 100%;
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+    font-size: 0.75rem;
+  }
+  /* The long ones, sized against the screen rather than at a fixed size.
+     A tab is a fifth of the viewport, so what fits in it is a function of the
+     viewport — and only roughly of the font size, since how wide a platform
+     renders a word varies by ten per cent or more between machines. A fixed
+     0.6rem fit here with ten pixels to spare and clipped in CI.
+
+     (These rules also used to sit above the one that sets the size for all
+     labels — identical specificity, later in the file, so nothing was ever
+     shortened.) */
+  .tab[data-tab="bookmarks"] .tab-label,
+  .tab[data-tab="statistics"] .tab-label {
+    font-size: clamp(0.46rem, 2.2vw, 0.62rem);
+  }
+  /* "Digital modes" does not fit at any size worth reading, so the nav shows
+     the short form and the button carries the full one as its label. */
+  .tab[data-tab="digital-modes"] .tab-label { display: none; }
+  .tab[data-tab="digital-modes"] .tab-label-short {
+    display: block;
+    max-width: 100%;
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+    font-size: clamp(0.46rem, 2.2vw, 0.62rem);
+  }
   .decoder-tab-select {
     display: block;
     width: 100%;
@@ -4060,10 +4124,18 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     flex: 0 0 auto;
     min-width: 0;
   }
+  /* The rig's name is the widest thing in the bar and it does not need to be:
+     139 px of a 338 px bar went on it, and everything else was pushed into the
+     overflow menu to make room. Enough for a short name, ellipsised past that,
+     with the full name still in the menu it opens. */
   .header-rig-switch select,
   .header-style-pick select {
     width: auto;
     min-width: 0;
+    max-width: 6.5rem;
+    padding-right: 0.2rem;
+    font-size: 0.8rem;
+    text-overflow: ellipsis;
   }
   .header-bar-btn {
     flex: 0 0 auto;
@@ -4094,12 +4166,20 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   .mult-col {
     min-width: 0;
   }
+  /* These are given the width of their column below; with padding on a
+     content box that is the column's width *plus* the padding, which is what
+     pushed the page itself sideways by a dozen pixels. */
   .wavelength-display,
   .sig-strength-display,
   .jog-step,
   .jog-mult {
+    box-sizing: border-box;
     width: 100%;
   }
+  .sig-strength-display {
+    min-width: 0;
+    font-size: 1.05rem;
+  }
   .jog-step button,
   .jog-mult button {
     flex: 1 1 0;
@@ -4123,47 +4203,6 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   .signal-measure #sig-result {
     width: 100%;
   }
-  #spectrum-controls {
-    flex-direction: column;
-    align-items: stretch;
-    gap: 0.45rem;
-    padding-top: 0.45rem;
-  }
-  #spectrum-bw-row,
-  #spectrum-level-row {
-    display: flex;
-    flex-wrap: wrap;
-    gap: 0.35rem 0.4rem;
-  }
-  #spectrum-bw-label,
-  #spectrum-floor-label,
-  #spectrum-range-label,
-  #spectrum-peak-hold-label {
-    flex: 1 1 100%;
-    justify-content: space-between;
-  }
-  #spectrum-gamma-label {
-    flex: 1 1 100%;
-    justify-content: space-between;
-  }
-  #spectrum-gamma-input {
-    flex: 1 1 auto;
-    min-width: 3rem;
-  }
-  #spectrum-bw-input,
-  #spectrum-floor-input,
-  #spectrum-range-input,
-  #overview-peak-hold {
-    flex: 1 1 auto;
-    min-width: 3rem;
-    box-sizing: border-box;
-  }
-  #spectrum-bw-set-btn,
-  #spectrum-bw-auto-btn,
-  #spectrum-bw-sweet-btn,
-  #spectrum-auto-btn {
-    flex: 1 1 auto;
-  }
   .spectrum-edge-shift {
     width: 0.95rem;
   }
@@ -4813,111 +4852,166 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
   white-space: nowrap;
   z-index: 10;
 }
+/* ── Spectrum control strip ────────────────────────────────────────────
+   Two clusters of controls under the plot: the receiver's bandwidth on the
+   left, the display's levels on the right.  Everything in here is one height
+   and one shape — a row whose controls each size themselves reads as a pile
+   rather than a strip.
+
+   The container wraps; a cluster does not.  A cluster that cannot fit drops
+   whole to the next line and starts it left-aligned, rather than splitting and
+   leaving the cluster beside it floating at a height of its own, which is what
+   the two rows did to each other between 1100 and 1400 px. */
 #spectrum-controls {
   display: flex;
   align-items: center;
-  justify-content: space-between;
+  flex-wrap: wrap;
   padding: 3px 4px 0;
-  gap: 0.6rem;
+  gap: 0.35rem 0.5rem;
   font-size: 0.78rem;
   color: var(--text-muted);
 }
-#spectrum-bw-row {
-  display: flex;
-  align-items: center;
-  flex-wrap: wrap;
-  gap: 0.4rem;
-}
-#spectrum-bw-label {
-  display: flex;
-  align-items: center;
-  gap: 0.3rem;
-  font-size: 0.75rem;
-  color: var(--text-muted);
-  min-width: 0;
-}
-#spectrum-bw-input {
-  width: 4.5rem;
-  padding: 1px 4px;
-  font-size: 0.75rem;
-  border: 1px solid var(--border);
-  border-radius: 4px;
-  background: var(--input-bg);
-  color: var(--text);
-  text-align: right;
-  height: 1.5rem;
-}
-#spectrum-bw-set-btn,
-#spectrum-bw-auto-btn,
-#spectrum-bw-sweet-btn {
-  height: 1.5rem;
-  min-height: 0;
-  padding: 0 8px;
-  font-size: 0.75rem;
-}
+#spectrum-bw-row,
 #spectrum-level-row {
   display: flex;
   align-items: center;
-  gap: 0.4rem;
+  flex-wrap: nowrap;
+  gap: 0.3rem;
 }
-#spectrum-floor-label {
-  display: flex;
+/* Takes the slack, so the clusters reach the ends of a wide strip without
+   `space-between` opening a quarter-width hole in the middle of it. */
+.spectrum-controls-spacer {
+  flex: 1 1 1.5rem;
+  min-width: 0;
+}
+
+/* A field is one box: name, value and unit share a border, so a number can
+   never be read apart from the unit it is in. */
+.spectrum-field {
+  display: inline-flex;
   align-items: center;
   gap: 0.3rem;
+  /* Border-box on both field and button, or the button's own border and
+     padding add to the height and the two end up a couple of pixels apart —
+     which is the pile-of-controls look this is meant to end. */
+  box-sizing: border-box;
+  height: 1.7rem;
+  padding: 0 0.4rem 0 0.5rem;
+  border: 1px solid var(--border-light);
+  border-radius: 6px;
+  background: var(--input-bg);
+  white-space: nowrap;
   font-size: 0.75rem;
   color: var(--text-muted);
 }
-#spectrum-floor-input {
-  width: 3.4rem;
-  padding: 1px 4px;
-  font-size: 0.75rem;
-  border: 1px solid var(--border);
-  border-radius: 4px;
-  background: var(--input-bg);
-  color: var(--text);
-  text-align: right;
-  height: 1.5rem;
+.spectrum-field:focus-within {
+  border-color: color-mix(in srgb, var(--accent-green) 45%, var(--border-light));
 }
-#spectrum-range-label {
-  display: flex;
-  align-items: center;
-  gap: 0.3rem;
-  font-size: 0.75rem;
+.spectrum-field-name {
+  font-size: 0.72rem;
   color: var(--text-muted);
 }
-#spectrum-range-input {
-  width: 3.4rem;
-  padding: 1px 4px;
-  font-size: 0.75rem;
-  border: 1px solid var(--border);
-  border-radius: 4px;
-  background: var(--input-bg);
+/* Unit and readout hold a fixed, tabular slot: the row must not twitch as a
+   value goes from 1.0 to 0.9. */
+.spectrum-field-unit,
+.spectrum-field-value {
+  font-size: 0.7rem;
+  color: var(--text-muted);
+  font-variant-numeric: tabular-nums;
+  min-width: 1.7rem;
+}
+.spectrum-field-value {
   color: var(--text);
   text-align: right;
-  height: 1.5rem;
 }
-#spectrum-auto-btn {
-  height: 1.5rem;
+.spectrum-field input[type="number"] {
+  width: 3.2rem;
+  padding: 0;
+  border: 0;
+  background: transparent;
+  color: var(--text);
+  font-size: 0.78rem;
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+}
+.spectrum-field input[type="number"]:focus {
+  outline: none;
+}
+#spectrum-bw-input {
+  width: 3.6rem;
+}
+/* The select carries `status-input` for the sake of other layouts, which gives
+   it a border and a background of its own; inside a field that reads as a box
+   drawn inside a box. */
+#spectrum-controls .spectrum-field select {
+  width: auto;
+  height: 1.35rem;
   min-height: 0;
-  padding: 0 8px;
-  font-size: 0.75rem;
+  padding: 0 0.1rem;
+  border: 0;
+  border-radius: 0;
+  background: transparent;
+  color: var(--text);
+  font-size: 0.74rem;
 }
-#spectrum-gamma-label {
-  display: flex;
-  align-items: center;
-  gap: 0.3rem;
-  font-size: 0.75rem;
-  color: var(--text-muted);
-}
-#spectrum-gamma-input {
-  width: 5rem;
-  height: 1.5rem;
+.spectrum-field input[type="range"] {
+  width: 5.5rem;
+  height: 1.2rem;
   cursor: pointer;
 }
-#spectrum-gamma-value {
-  font-size: 0.75rem;
-  min-width: 1.6rem;
-  text-align: right;
+.spectrum-btn {
+  box-sizing: border-box;
+  height: 1.7rem;
+  min-height: 0;
+  padding: 0 0.6rem;
+  border-radius: 6px;
+  font-size: 0.73rem;
+  font-weight: 600;
+  white-space: nowrap;
+}
+/* Fingers need more than a 27 px target; a mouse does not, and the strip has
+   no width to spare on a desktop. */
+@media (hover: none) and (pointer: coarse) {
+  .spectrum-field,
+  .spectrum-btn {
+    height: 2.4rem;
+  }
+}
+
+/* Narrow screens: the same fields, stacked. This sits after the rules it
+   overrides — `#spectrum-bw-row` in both places has identical specificity, so
+   whichever comes last wins, and from inside the earlier media query the
+   narrow rules silently lost. */
+@media (max-width: 640px) {
+  /* Narrow: the clusters stack, and a field takes the width so its name and
+     its value sit at opposite ends of a line the thumb can hit. */
+  #spectrum-controls {
+    flex-direction: column;
+    align-items: stretch;
+    gap: 0.45rem;
+    padding-top: 0.45rem;
+  }
+  #spectrum-bw-row,
+  #spectrum-level-row {
+    flex-wrap: wrap;
+    gap: 0.35rem 0.4rem;
+  }
+  .spectrum-controls-spacer {
+    display: none;
+  }
+  #spectrum-controls .spectrum-field {
+    flex: 1 1 100%;
+    justify-content: space-between;
+  }
+  #spectrum-controls .spectrum-field input[type="number"],
+  #spectrum-controls .spectrum-field input[type="range"],
+  #spectrum-controls .spectrum-field select {
+    flex: 1 1 auto;
+    min-width: 3rem;
+  }
+  #spectrum-controls .spectrum-btn {
+    flex: 1 1 auto;
+  }
 }
 .spectrum-hint-mouse,
 .spectrum-hint-touch {
@@ -4936,9 +5030,15 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
 
 /* ── Phone layout (≤ 520px) ───────────────────────────────────────────── */
 @media (max-width: 520px) {
-  /* Single-column controls: jog first, then mode, then power */
+  /* Single-column controls: jog first, then mode, then power.
+     `nowrap` is the whole point of it. The base rule wraps, and a *column*
+     that wraps starts a second column when its items are taller than it is —
+     which put the transmit controls at x=400 on a 390 px screen, off the side
+     of a tray 354 px wide, reachable only by a horizontal scroll with nothing
+     to say it was there. */
   .controls-row {
     flex-direction: column;
+    flex-wrap: nowrap;
     align-items: stretch;
   }
   .controls-col-center {
@@ -6127,8 +6227,16 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
 .controls-tray { container-type: inline-size; container-name: controls; }
 .decode-history-table-wrap { container-type: inline-size; container-name: decode-table; }
 
-@container controls (max-width: 600px) {
-  .controls-tray .controls-row { flex-wrap: wrap; }
+/* Wrapping a narrow tray's columns onto more lines is right while the row runs
+   left to right. Below the phone breakpoint the row is a column, and wrap there
+   means "start another column" — which is how the transmit controls ended up
+   beside the tray instead of under it, off the side of the screen. This rule
+   outranks the phone one (two classes to its one) and sits later in the file,
+   so it has to exclude itself rather than be overridden. */
+@media (min-width: 521px) {
+  @container controls (max-width: 600px) {
+    .controls-tray .controls-row { flex-wrap: wrap; }
+  }
 }
 @container decode-table (max-width: 500px) {
   .decode-history-table th:nth-child(n+4),

src/trx-client/trx-frontend/trx-frontend-http/frontend/build.mjs

@@ -23,12 +23,14 @@ await build({
     ft8: path.join(sourceDir, "plugins", "ft8.ts"),
     vdes: path.join(sourceDir, "plugins", "vdes.ts"),
     wefax: path.join(sourceDir, "plugins", "wefax.ts"),
+    sstv: path.join(sourceDir, "plugins", "sstv.ts"),
     "background-decode": path.join(sourceDir, "plugins", "background-decode.ts"),
     ais: path.join(sourceDir, "plugins", "ais.ts"),
     aprs: path.join(sourceDir, "plugins", "aprs.ts"),
     "hf-aprs": path.join(sourceDir, "plugins", "hf-aprs.ts"),
     sat: path.join(sourceDir, "plugins", "sat.ts"),
     "sat-scheduler": path.join(sourceDir, "plugins", "sat-scheduler.ts"),
+    "satellite-predictions": path.join(sourceDir, "plugins", "satellite-predictions.ts"),
     vchan: path.join(sourceDir, "plugins", "vchan.ts"),
     bookmarks: path.join(sourceDir, "plugins", "bookmarks.ts"),
     scheduler: path.join(sourceDir, "plugins", "scheduler.ts"),

src/trx-client/trx-frontend/trx-frontend-http/frontend/package.json

@@ -12,7 +12,7 @@
     "typecheck": "tsc --project tsconfig.json && tsc --project tsconfig.worker.json",
     "lint": "eslint \"src/**/*.ts\" \"tests/**/*.mjs\" build.mjs --no-error-on-unmatched-pattern",
     "test": "node --test tests/*.test.mjs",
-    "test:browser": "node tests/browser-smoke.mjs && node tests/spectrum-layout.mjs && node tests/decode-flow.mjs",
+    "test:browser": "node tests/browser-smoke.mjs && node tests/spectrum-layout.mjs && node tests/decode-flow.mjs && node tests/tune-links.mjs && node tests/mobile-layout.mjs && node tests/satellite-predictions.mjs",
     "verify-generated": "npm run generate-types && npm run build && git diff --exit-code -- ../assets/web/generated src/api/generated.ts"
   },
   "devDependencies": {

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/api/generated.ts

@@ -51,7 +51,7 @@ export type RigRxStatus = { sig: number | null, };
 
 export type RigStatus = { freq: Freq, mode: RigMode, tx_en: boolean, vfo: RigVfo | null, tx: RigTxStatus | null, rx: RigRxStatus | null, lock: boolean | null, };
 
-export type DecoderConfig = { aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, recorder_enabled: boolean, };
+export type DecoderConfig = { aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, sstv_decode_enabled: boolean, recorder_enabled: boolean, };
 
 export type WfmDenoiseLevel = "off" | "auto" | "low" | "medium" | "high";
 
@@ -78,6 +78,10 @@ export type RdsData = { pi?: number | null, program_service?: string | null, rad
 export type SpectrumData = { 
 /**
  * FFT magnitude bins in dBFS, FFT-shifted so DC (centre frequency) is at index N/2.
+ *
+ * On the wire these are base64-encoded `i8` whole dBFS (see
+ * `spectrum_wire`), which is what the display draws anyway; the TypeScript
+ * type describes the decoded array the browser receives over SSE.
  */
 bins: Array<number>, 
 /**
@@ -111,7 +115,7 @@ export type RigSnapshot = { info: RigInfo, status: RigStatus, band: string | nul
 /**
  * Per-virtual-channel RDS snapshots, when available.
  */
-vchan_rds?: Array<VchanRdsEntry> | null, aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, recorder_enabled: boolean, };
+vchan_rds?: Array<VchanRdsEntry> | null, aprs_decode_enabled: boolean, hf_aprs_decode_enabled: boolean, cw_decode_enabled: boolean, ft8_decode_enabled: boolean, ft4_decode_enabled: boolean, ft2_decode_enabled: boolean, wspr_decode_enabled: boolean, lrpt_decode_enabled: boolean, wefax_decode_enabled: boolean, sstv_decode_enabled: boolean, recorder_enabled: boolean, };
 
 export type RigListItem = { remote: string, display_name: string | null, manufacturer: string, model: string, supported_modes: Array<RigMode>, tx: boolean, filter_controls: boolean, initialized: boolean, latitude: number | null, longitude: number | null, };
 

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.ts

@@ -34,7 +34,10 @@ import {
 import { decodeCbor as decodeCborPayload } from "./core/cbor.js";
 import {
   TAB_ORDER,
+  type TuneLink,
+  parseTuneLink,
   tabFromPath as tabFromPathname,
+  tuneLinkSearch,
   updateTabHistory,
 } from "./features/navigation/routes.js";
 import { estimateOccupiedBandwidth } from "./features/radio/auto-bandwidth.js";
@@ -382,7 +385,9 @@ declare global {
     refreshCwTonePicker?(): void;
     updateFt8RfDisplay?(): void;
     clearSatPredictionDom?(): void;
+    refreshSatPredictions?(): void;
     syncWefaxToggle?(enabled: boolean): void;
+    syncSstvToggle?(enabled: boolean): void;
     updateAisBar?(value?: number): void;
     updateVdesBar?(value?: number): void;
     updateAprsBar?(value?: number): void;
@@ -609,6 +614,7 @@ function applyAuthRestrictions() {
 function applyCapabilities(caps: RigCapabilities | null) {
   if (!caps) return;
   lastHasTx = !!caps.tx;
+  bandwidthControlSupported = !!caps.filter_controls;
   if (signalVisualBlockEl) signalVisualBlockEl.style.display = "";
 
   // PTT / TX controls
@@ -854,7 +860,7 @@ function currentDecodeHistoryRetentionMs() {
 window.getDecodeHistoryRetentionMs = currentDecodeHistoryRetentionMs;
 
 window.applyDecodeHistoryRetention = function() {
-  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax"]) {
+  for (const decoder of ["aprs", "hf_aprs", "ais", "vdes", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"]) {
     window.trxPluginRuntime.prune(decoder);
   }
 };
@@ -1012,6 +1018,9 @@ let jogAngle = 0;
 let lastClientCount: number | null = null;
 let lastLocked = false;
 let sdrSquelchSupported = false;
+// Whether this rig takes a bandwidth at all — a CAT rig without filter control
+// has no use for the `bw` of a tune link, in either direction.
+let bandwidthControlSupported = false;
 // ── Previous-state tracking for "B" hotkey ────────────────────────────────────
 let previousTuneState: PreviousTuneState | null = null;
 
@@ -3267,6 +3276,110 @@ window.buildAisVesselUrl = function(mmsi: unknown) {
   return `${aisVesselUrlBase}${String(mmsi)}`;
 };
 
+// ---------------------------------------------------------------------------
+// Tune links
+//
+// The address bar is the share link: whatever the dial is on is in the query
+// string, and a link someone else opens puts the radio there.  Read the
+// incoming link once, at load, before anything of ours rewrites the URL.
+// ---------------------------------------------------------------------------
+
+const incomingTuneLink: TuneLink = parseTuneLink(window.location.search);
+// "pending" until the first state arrives, "applying" while the link is being
+// followed, "live" once the URL is ours to keep up to date.
+let tuneLinkPhase: "pending" | "applying" | "live" = "pending";
+let tuneLinkSyncTimer: number | null = null;
+
+function currentTuneLink(): TuneLink {
+  const bandwidthHz = bandwidthControlSupported && isFiniteNumber(currentBandwidthHz) && currentBandwidthHz > 0
+    ? currentBandwidthHz
+    : null;
+  return {
+    rig: lastActiveRigId || null,
+    freqHz: isFiniteNumber(lastFreqHz) ? lastFreqHz : null,
+    mode: lastModeName || null,
+    bandwidthHz,
+  };
+}
+
+/** The link as someone else would open it. */
+function tuneLinkUrl(): string {
+  const search = tuneLinkSearch(window.location.search, currentTuneLink());
+  return `${window.location.origin}${window.location.pathname}${search}${window.location.hash}`;
+}
+
+function scheduleTuneLinkSync() {
+  if (tuneLinkPhase !== "live") return;
+  // A virtual channel is a tab's own slice, not where the rig is pointed —
+  // publishing it as the rig's link would send someone to another frequency.
+  if (window.trx?.modules.vchan?.isOnVirtual() === true) return;
+  if (tuneLinkSyncTimer != null) return;
+  tuneLinkSyncTimer = window.setTimeout(() => {
+    tuneLinkSyncTimer = null;
+    const search = tuneLinkSearch(window.location.search, currentTuneLink());
+    if (search === window.location.search) return;
+    // replaceState, not push: tuning is not navigation, and a dial sweep would
+    // otherwise bury the back button under a hundred entries.
+    window.history.replaceState({}, "", `${window.location.pathname}${search}${window.location.hash}`);
+  }, 500);
+}
+
+async function applyTuneLink(link: TuneLink) {
+  const wanted = link.rig || link.mode || link.freqHz != null || link.bandwidthHz != null;
+  if (!wanted) return;
+  if (authRole === "rx") {
+    showHint("Read-only session — link not applied", 2500);
+    return;
+  }
+  // Rig first: the rest of the link describes state on that rig.
+  if (link.rig && headerRigSwitchSelect && link.rig !== lastActiveRigId && lastRigIds.includes(link.rig)) {
+    headerRigSwitchSelect.value = link.rig;
+    await switchRigFromSelect(headerRigSwitchSelect);
+  }
+  // Mode before frequency: the mode change carries a default bandwidth with
+  // it, which an explicit bw in the link then overrides.
+  if (link.mode && link.mode !== lastModeName && modeEl) {
+    const known = Array.from(modeEl.options).some((option) => option.value === link.mode);
+    if (known) {
+      modeEl.value = link.mode;
+      await applyModeFromPicker();
+    } else {
+      showHint(`Rig has no ${link.mode} mode`, 2500);
+    }
+  }
+  if (link.freqHz != null) {
+    // setRigFrequency throws on a frequency this rig cannot reach, having
+    // already told the user which one it was.
+    try { setRigFrequency(link.freqHz); } catch { /* reported to the user */ }
+  }
+  if (link.bandwidthHz != null && bandwidthControlSupported && spectrumBwInput) {
+    spectrumBwInput.value = String(link.bandwidthHz / 1000);
+    await applyBandwidthFromInput();
+  }
+}
+
+function followTuneLinkOnce() {
+  if (tuneLinkPhase !== "pending") return;
+  tuneLinkPhase = "applying";
+  void applyTuneLink(incomingTuneLink).finally(() => {
+    tuneLinkPhase = "live";
+    scheduleTuneLinkSync();
+  });
+}
+
+async function copyTuneLink() {
+  const url = tuneLinkUrl();
+  try {
+    await navigator.clipboard.writeText(url);
+    showHint("Link copied", 1500);
+  } catch {
+    window.trxUi?.notify("Clipboard unavailable — the address bar holds the link", { kind: "error" });
+  }
+}
+
+const shareLinkBtn = document.getElementById("header-share-btn") as HTMLButtonElement | null;
+if (shareLinkBtn) shareLinkBtn.addEventListener("click", () => { void copyTuneLink(); });
+
 function render(update: AppUpdate) {
   if (!update) return;
   if (update.server_version) serverVersion = update.server_version;
@@ -3601,7 +3714,11 @@ function render(update: AppUpdate) {
   for (const [key, entry] of Object.entries(_decoderToggles)) {
     syncDecoderToggle(entry, !!update[key], entry.label);
   }
-  // WEFAX toggle sync (plugin-owned, belt-and-suspenders alongside _decoderToggles).
+  // Image decoders own their own toggle buttons; keep them in step with the
+  // rig state as well as with the click that set it.
+  if (typeof update.sstv_decode_enabled === "boolean" && window.syncSstvToggle) {
+    window.syncSstvToggle(update.sstv_decode_enabled);
+  }
   if (typeof update.wefax_decode_enabled === "boolean" && window.syncWefaxToggle) {
     window.syncWefaxToggle(update.wefax_decode_enabled);
   }
@@ -3842,6 +3959,10 @@ function render(update: AppUpdate) {
     swrBar.style.width = "0%";
     swrValue.textContent = "SWR --";
   }
+  // Follow the link that opened the page once there is a rig to point, then
+  // keep the address bar on whatever the dial does next.
+  if (update.status) followTuneLinkOnce();
+  scheduleTuneLinkSync();
 }
 
 function scheduleReconnect(delayMs = 1000) {
@@ -4729,6 +4850,7 @@ function _initMapWhenReady() {
 
 function navigateToTab(name: TabName, options: { updateHistory?: boolean; replaceHistory?: boolean } = {}) {
   window.trxUi?.closeMobileOverlays?.();
+  const leavingSatellites = _activeTab === "satellites" && name !== "satellites";
   const { updateHistory = true, replaceHistory = false } = options;
   if (authEnabled && !authRole && name !== "main") {
     showAuthGate(false);
@@ -4769,7 +4891,13 @@ function navigateToTab(name: TabName, options: { updateHistory?: boolean; replac
     updateTabHistory(name, replaceHistory);
   }
   scheduleSpectrumLayout();
-  void loadPluginsForTab(name).catch((error: unknown) => { console.error(error); });
+  // Its countdowns tick every second, so the page stops when it is not on screen.
+  if (leavingSatellites) window.clearSatPredictionDom?.();
+  void loadPluginsForTab(name).then(() => {
+    // Passes go stale while the page is closed, so each visit reloads them.
+    // The first visit is what imports the module, which renders on its own.
+    if (name === "satellites") window.refreshSatPredictions?.();
+  }).catch((error: unknown) => { console.error(error); });
   if (name === "map") {
     _initMapWhenReady();
   }
@@ -5121,10 +5249,6 @@ function _wireSubTabBar(bar: WiredElement) {
         if (window.refreshCwTonePicker) window.refreshCwTonePicker();
       });
     }
-    // Clear SAT prediction DOM when leaving the SAT tab to reduce node count.
-    if (btn.dataset.subtab !== "sat" && typeof window.clearSatPredictionDom === "function") {
-      window.clearSatPredictionDom();
-    }
   });
 }
 document.querySelectorAll<WiredElement>(".sub-tab-bar").forEach(_wireSubTabBar);
@@ -6452,9 +6576,15 @@ function updateDecodeStatus(text: string) {
     if (el && el.textContent !== "Receiving") el.textContent = text;
   }
 }
+// Picture decoders produce one message per image and a stream of progress
+// updates; neither is a spot, and counting them would swamp the statistics.
+const IMAGE_DECODE_KINDS = new Set([
+  "lrpt_image", "lrpt_progress", "wefax", "wefax_progress", "sstv", "sstv_progress",
+]);
+
 function dispatchDecodeMessage(msg: DecodeMessage, skipStats = false) {
   if (msg.type) window.trxPluginRuntime.dispatch(msg.type, msg);
-  if (!skipStats && msg.type && msg.type !== "lrpt_image" && msg.type !== "lrpt_progress" && msg.type !== "wefax" && msg.type !== "wefax_progress") {
+  if (!skipStats && msg.type && !IMAGE_DECODE_KINDS.has(msg.type)) {
     window.trx.modules.map?.statsRecordDecode(msg.type, msg.rig_id || msg.remote || null);
     window.trx.modules.map?.scheduleStatsRender();
   }
@@ -6504,7 +6634,7 @@ function loadDecodeHistoryOnMainThread(onReady: (groups: DecodeHistoryGroups) =>
 function restoreDecodeHistoryGroup(kind: string, messages: DecodeMessage[]) {
   if (!Array.isArray(messages) || messages.length === 0) return;
   // Record statistics for restored history messages.
-  if (kind !== "lrpt_image" && kind !== "lrpt_progress" && kind !== "wefax" && kind !== "wefax_progress") {
+  if (!IMAGE_DECODE_KINDS.has(kind)) {
     for (const msg of messages) {
       window.trx.modules.map?.statsRecordDecode(kind, msg.rig_id || msg.remote || null, msg.ts_ms || undefined);
     }

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/decode-history-worker.ts

@@ -5,7 +5,7 @@
 export {};
 
 const textDecoder = typeof TextDecoder === "function" ? new TextDecoder() : null;
-const HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax"] as const;
+const HISTORY_GROUP_KEYS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"] as const;
 type HistoryGroup = (typeof HISTORY_GROUP_KEYS)[number];
 type CborValue = number | string | boolean | null | undefined | CborValue[] | { [key: string]: CborValue };
 interface DecodeState { offset: number }

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/features/navigation/routes.ts

@@ -3,7 +3,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 export const TAB_ORDER = [
-  "main", "bookmarks", "digital-modes", "map", "statistics", "recorder", "settings", "about",
+  "main", "bookmarks", "digital-modes", "map", "satellites", "statistics", "recorder", "settings", "about",
 ] as const;
 
 export type TabName = typeof TAB_ORDER[number];
@@ -13,6 +13,7 @@ export const TAB_PATHS: Readonly<Record<TabName, string>> = {
   bookmarks: "/bookmarks",
   "digital-modes": "/digital-modes",
   map: "/map",
+  satellites: "/satellites",
   statistics: "/statistics",
   recorder: "/recorder",
   settings: "/settings",
@@ -37,3 +38,66 @@ export function updateTabHistory(name: TabName, replace = false): void {
   if (replace) window.history.replaceState({}, "", nextUrl);
   else window.history.pushState({}, "", nextUrl);
 }
+
+/** What a shared link says to listen to: `?rig=sdr&f=14074000&mode=USB&bw=3000`. */
+export interface TuneLink {
+  rig: string | null;
+  freqHz: number | null;
+  mode: string | null;
+  bandwidthHz: number | null;
+}
+
+const FREQ_MULTIPLIER: Readonly<Record<string, number>> = { k: 1e3, m: 1e6, g: 1e9 };
+
+/**
+ * Read a frequency written for a person: bare Hz as the canonical form, but
+ * `7074k` and `14.074M` are what someone typing a link by hand reaches for.
+ * Returns Hz, or null for anything that is not a positive frequency.
+ */
+export function parseFrequencyParam(raw: string | null | undefined): number | null {
+  if (typeof raw !== "string") return null;
+  const text = raw.trim().toLowerCase().replace(/hz$/, "").trim();
+  const match = /^(\d+(?:\.\d+)?)\s*([kmg]?)$/.exec(text);
+  if (!match) return null;
+  const value = Number(match[1]) * (FREQ_MULTIPLIER[match[2] ?? ""] ?? 1);
+  if (!Number.isFinite(value) || value <= 0) return null;
+  return Math.round(value);
+}
+
+/** Mode names run from FM to VDES; anything else in the URL is not one. */
+function parseModeParam(raw: string | null | undefined): string | null {
+  const mode = typeof raw === "string" ? raw.trim().toUpperCase() : "";
+  return /^[A-Z]{2,4}$/.test(mode) ? mode : null;
+}
+
+export function parseTuneLink(search: string): TuneLink {
+  const params = new URLSearchParams(search);
+  const rig = (params.get("rig") || "").trim();
+  return {
+    rig: rig || null,
+    freqHz: parseFrequencyParam(params.get("f")),
+    mode: parseModeParam(params.get("mode")),
+    bandwidthHz: parseFrequencyParam(params.get("bw")),
+  };
+}
+
+/**
+ * Rewrite the tune parameters of a query string, leaving anything else in it
+ * alone — the address bar is the share link, so it has to keep up with the
+ * dial without discarding whatever else a page put there.
+ */
+export function tuneLinkSearch(search: string, link: TuneLink): string {
+  const params = new URLSearchParams(search);
+  const set = (key: string, value: string | null) => {
+    if (value == null || value === "") params.delete(key);
+    else params.set(key, value);
+  };
+  const hz = (value: number | null) =>
+    (typeof value === "number" && Number.isFinite(value) && value > 0 ? String(Math.round(value)) : null);
+  set("rig", link.rig);
+  set("f", hz(link.freqHz));
+  set("mode", parseModeParam(link.mode));
+  set("bw", hz(link.bandwidthHz));
+  const text = params.toString();
+  return text ? `?${text}` : "";
+}

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugin-loader.ts

@@ -2,7 +2,9 @@
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-type PluginGroup = "digital-modes" | "map-data" | "map" | "statistics" | "bookmarks" | "recorder" | "settings";
+type PluginGroup =
+  | "digital-modes" | "map-data" | "map" | "satellites" | "statistics"
+  | "bookmarks" | "recorder" | "settings";
 
 const pluginGroups: Readonly<Record<PluginGroup, readonly string[]>> = {
   // AIS, VDES and the two APRS decoders have panels on this tab, so they load
@@ -11,10 +13,11 @@ const pluginGroups: Readonly<Record<PluginGroup, readonly string[]>> = {
   // the Map tab. Their map calls are optional, so map-core stays lazy.
   "digital-modes": [
     "/ft8.js", "/ft4.js", "/ft2.js", "/wspr.js", "/cw.js", "/background-decode.js",
-    "/sat.js", "/wefax.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js",
+    "/sat.js", "/wefax.js", "/sstv.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js",
   ],
   "map-data": ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js"],
   map: ["/map-core.js", "/ais.js", "/vdes.js", "/aprs.js", "/hf-aprs.js", "/sat.js", "/sat-scheduler.js"],
+  satellites: ["/satellite-predictions.js"],
   statistics: ["/map-core.js"],
   bookmarks: ["/bookmarks.js"],
   recorder: [],

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/sat.ts

@@ -4,13 +4,12 @@
 
 import { hostCore } from "./host.js";
 
-import type { LrptProgress, SatelliteImage, SatelliteLiveUpdate, SatellitePass, SatellitePassResponse } from "./satellite-types";
+import type { LrptProgress, SatelliteImage, SatelliteLiveUpdate } from "./satellite-types";
 import type { PluginRuntimeWindow } from "./runtime-contract.js";
 
-type SatelliteView = "live" | "history" | "predictions";
+type SatelliteView = "live" | "history";
 interface SatelliteBridge {
   trxScheduleUiFrameJob?: (key: string, job: () => void) => void;
-  clearSatPredictionDom?: () => void;
   updateSatLiveState?: (update: SatelliteLiveUpdate) => void;
   addSatMapOverlay?: (image: SatelliteImage) => void;
   clearSatMapOverlays?: () => void;
@@ -25,14 +24,14 @@ const satWindow = window as unknown as SatelliteBridge & PluginRuntimeWindow;
 // --- SAT Plugin ---
 // Live view: decoder state, latest image card
 // History view: filterable table of all decoded images
-// Predictions view: next 24 h passes for ham satellites
+//
+// Pass predictions live on their own page; see satellite-predictions.ts.
 
 // ── DOM references (cached once) ───────────────────────────────────
 const satDom = {
   status:           document.getElementById("sat-status"),
   liveView:         document.getElementById("sat-live-view"),
   historyView:      document.getElementById("sat-history-view"),
-  predictionsView:  document.getElementById("sat-predictions-view"),
   liveLatest:       document.getElementById("sat-live-latest"),
   historyList:      document.getElementById("sat-history-list"),
   historyCount:     document.getElementById("sat-history-count"),
@@ -42,30 +41,13 @@ const satDom = {
   lrptState:        document.getElementById("sat-lrpt-state"),
   viewLiveBtn:      document.getElementById("sat-view-live"),
   viewHistoryBtn:   document.getElementById("sat-view-history"),
-  viewPredBtn:      document.getElementById("sat-view-predictions"),
-  predFilter:       document.getElementById("sat-pred-filter") as HTMLInputElement | null,
-  predMinEl:        document.getElementById("sat-pred-min-el") as HTMLSelectElement | null,
-  predCategory:     document.getElementById("sat-pred-category") as HTMLSelectElement | null,
-  predCurrentList:  document.getElementById("sat-pred-current-list"),
-  predUpcomingList: document.getElementById("sat-pred-list"),
-  predCurrentSec:   document.getElementById("sat-pred-current-section"),
-  predUpcomingSec:  document.getElementById("sat-pred-upcoming-section"),
-  predStatus:       document.getElementById("sat-pred-status"),
 };
 
 // ── State ───────────────────────────────────────────────────────────
 let satImageHistory: SatelliteImage[] = [];
 const SAT_MAX_IMAGES = 100;
-const SAT_PRED_PAGE_SIZE = 50;
-let satPredShowAll = false;
 let satFilterText = "";
 let satActiveView: SatelliteView = "live";
-let satPredData: SatellitePass[] = [];
-let satPredFilterText = "";
-let satPredMinEl = 0;
-let satPredCategory = "all";
-let satPredSatCount = 0;
-let satPredCountdownTimer: ReturnType<typeof setInterval> | null = null;
 
 // ── UI scheduler helper ─────────────────────────────────────────────
 function scheduleSatUi(key: string, job: () => void): void {
@@ -78,33 +60,16 @@ function scheduleSatUi(key: string, job: () => void): void {
 
 // ── View switching ──────────────────────────────────────────────────
 function switchSatView(view: SatelliteView): void {
-  const leavingPredictions = satActiveView === "predictions" && view !== "predictions";
   satActiveView = view;
-  if (satDom.liveView)        satDom.liveView.style.display = view === "live" ? "" : "none";
-  if (satDom.historyView)     satDom.historyView.style.display = view === "history" ? "" : "none";
-  if (satDom.predictionsView) satDom.predictionsView.style.display = view === "predictions" ? "" : "none";
-  if (satDom.viewLiveBtn)     satDom.viewLiveBtn.classList.toggle("sat-view-active", view === "live");
-  if (satDom.viewHistoryBtn)  satDom.viewHistoryBtn.classList.toggle("sat-view-active", view === "history");
-  if (satDom.viewPredBtn)     satDom.viewPredBtn.classList.toggle("sat-view-active", view === "predictions");
-  if (leavingPredictions) clearPredictionDom();
-  if (view === "history") {
-    renderSatHistoryTable();
-  } else if (view === "predictions") {
-    satPredShowAll = false;
-    void loadSatPredictions();
-  }
+  if (satDom.liveView)       satDom.liveView.style.display = view === "live" ? "" : "none";
+  if (satDom.historyView)    satDom.historyView.style.display = view === "history" ? "" : "none";
+  if (satDom.viewLiveBtn)    satDom.viewLiveBtn.classList.toggle("sat-view-active", view === "live");
+  if (satDom.viewHistoryBtn) satDom.viewHistoryBtn.classList.toggle("sat-view-active", view === "history");
+  if (view === "history") renderSatHistoryTable();
 }
 
-function clearPredictionDom() {
-  stopCountdownTimer();
-  if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-}
-satWindow.clearSatPredictionDom = clearPredictionDom;
-
 satDom.viewLiveBtn?.addEventListener("click", () => { switchSatView("live"); });
 satDom.viewHistoryBtn?.addEventListener("click", () => { switchSatView("history"); });
-satDom.viewPredBtn?.addEventListener("click", () => { switchSatView("predictions"); });
 
 // ── Live view: decoder state ────────────────────────────────────────
 let lastSatLrptOn: boolean | null = null;
@@ -335,234 +300,6 @@ document
     }
   })(); });
 
-// ── Predictions: helpers ────────────────────────────────────────────
-function azToCardinal(deg: number): string {
-  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
-  return dirs[Math.round(deg / 45) % 8] ?? "N";
-}
-
-function formatPredTime(ms: number): string {
-  const d = new Date(ms);
-  const now = new Date();
-  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
-  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
-  const hh = String(d.getUTCHours()).padStart(2, "0");
-  const mm = String(d.getUTCMinutes()).padStart(2, "0");
-  return `${day}${hh}:${mm}`;
-}
-
-function formatPredDuration(s: number): string {
-  if (s >= 60) return `${Math.round(s / 60)} min`;
-  return `${s}s`;
-}
-
-function formatCountdown(ms: number): string {
-  const totalSec = Math.max(0, Math.floor(ms / 1000));
-  const m = Math.floor(totalSec / 60);
-  const s = totalSec % 60;
-  return `${m}:${String(s).padStart(2, "0")}`;
-}
-
-function elevationClass(deg: number): string {
-  if (deg >= 45) return "sat-pred-el-high";
-  if (deg >= 10) return "sat-pred-el-mid";
-  return "sat-pred-el-low";
-}
-
-// ── Predictions: countdown timer management ─────────────────────────
-function stopCountdownTimer() {
-  if (satPredCountdownTimer) {
-    clearInterval(satPredCountdownTimer);
-    satPredCountdownTimer = null;
-  }
-}
-
-function startCountdownTimer(container: HTMLElement | null): void {
-  const countdownEls = container?.querySelectorAll<HTMLElement>(".sat-pred-col-countdown") ?? [];
-  if (countdownEls.length === 0) return;
-
-  satPredCountdownTimer = setInterval(() => {
-    if (satActiveView !== "predictions") {
-      stopCountdownTimer();
-      return;
-    }
-    const n = Date.now();
-    let anyActive = false;
-    for (const el of countdownEls) {
-      const los = Number.parseInt(el.dataset.los ?? "0", 10);
-      const rem = los - n;
-      if (rem > 0) {
-        el.textContent = formatCountdown(rem);
-        anyActive = true;
-      } else {
-        el.textContent = "0:00";
-      }
-    }
-    if (!anyActive) {
-      stopCountdownTimer();
-      renderSatPredictions(getFilteredPredictions());
-    }
-  }, 1000);
-}
-
-// ── Predictions: row builders ───────────────────────────────────────
-function buildCurrentPassRow(pass: SatellitePass, now: number): HTMLElement {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row-current";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
-  const remaining = Math.max(0, pass.los_ms - now);
-  row.innerHTML = [
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
-    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`,
-  ].join("");
-  return row;
-}
-
-function buildUpcomingPassRow(pass: SatellitePass): HTMLElement {
-  const row = document.createElement("div");
-  row.className = "sat-pred-row";
-  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
-  row.innerHTML = [
-    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
-    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
-    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
-    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
-    `<span class="sat-pred-col-dir">${dir}</span>`,
-  ].join("");
-  return row;
-}
-
-// ── Predictions: filter state ───────────────────────────────────────
-function getFilteredPredictions(): SatellitePass[] {
-  let items = satPredData;
-  if (satPredCategory !== "all") items = items.filter((p) => p.category === satPredCategory);
-  if (satPredMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= satPredMinEl);
-  if (satPredFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(satPredFilterText));
-  return items;
-}
-
-function applyPredFilters() {
-  renderSatPredictions(getFilteredPredictions());
-}
-
-const satPredictionFilter = satDom.predFilter;
-satPredictionFilter?.addEventListener("input", () => {
-  satPredFilterText = satPredictionFilter.value.trim().toUpperCase();
-  applyPredFilters();
-});
-
-const satPredictionMinElevation = satDom.predMinEl;
-satPredictionMinElevation?.addEventListener("change", () => {
-  satPredMinEl = Number.parseInt(satPredictionMinElevation.value, 10) || 0;
-  applyPredFilters();
-});
-
-const satPredictionCategory = satDom.predCategory;
-satPredictionCategory?.addEventListener("change", () => {
-  satPredCategory = satPredictionCategory.value;
-  applyPredFilters();
-});
-
-// ── Predictions: main render ────────────────────────────────────────
-function renderSatPredictions(passes: SatellitePass[], error?: string): void {
-  stopCountdownTimer();
-
-  if (error) {
-    if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec)   satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec)  satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus)       satDom.predStatus.textContent = error;
-    return;
-  }
-
-  if (!Array.isArray(passes) || passes.length === 0) {
-    if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-    if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-    if (satDom.predCurrentSec)   satDom.predCurrentSec.style.display = "none";
-    if (satDom.predUpcomingSec)  satDom.predUpcomingSec.style.display = "none";
-    if (satDom.predStatus)       satDom.predStatus.textContent = "No passes found in the next 24 hours.";
-    return;
-  }
-
-  const now = Date.now();
-  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
-  const upcoming = passes.filter((p) => p.aos_ms > now);
-
-  // ── Current passes ──
-  if (satDom.predCurrentSec) satDom.predCurrentSec.style.display = current.length > 0 ? "" : "none";
-  if (satDom.predCurrentList) {
-    if (current.length === 0) {
-      satDom.predCurrentList.innerHTML = "";
-    } else {
-      const frag = document.createDocumentFragment();
-      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
-      satDom.predCurrentList.replaceChildren(frag);
-    }
-  }
-
-  // ── Upcoming passes ──
-  const upcomingLimit = satPredShowAll ? upcoming.length : SAT_PRED_PAGE_SIZE;
-  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
-  const hiddenCount = upcoming.length - visibleUpcoming.length;
-  if (satDom.predUpcomingSec) satDom.predUpcomingSec.style.display = upcoming.length > 0 ? "" : "none";
-  if (satDom.predUpcomingList) {
-    const frag = document.createDocumentFragment();
-    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
-    if (hiddenCount > 0) {
-      const moreRow = document.createElement("div");
-      moreRow.className = "sat-pred-row";
-      moreRow.style.cursor = "pointer";
-      moreRow.style.textAlign = "center";
-      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes\u2026</span>`;
-      moreRow.addEventListener("click", () => {
-        satPredShowAll = true;
-        renderSatPredictions(getFilteredPredictions());
-      });
-      frag.appendChild(moreRow);
-    }
-    satDom.predUpcomingList.replaceChildren(frag);
-  }
-
-  // ── Status ──
-  if (satDom.predStatus) {
-    let text = `${current.length} active \u00B7 ${upcoming.length} upcoming \u00B7 times in UTC`;
-    if (satPredSatCount > 0) text += ` \u00B7 ${satPredSatCount} satellites tracked`;
-    satDom.predStatus.textContent = text;
-  }
-
-  // ── Countdown timer ──
-  if (current.length > 0 && satActiveView === "predictions") {
-    startCountdownTimer(satDom.predCurrentList);
-  }
-}
-
-// ── Predictions: data loading ───────────────────────────────────────
-async function loadSatPredictions(): Promise<void> {
-  if (satDom.predStatus)       satDom.predStatus.textContent = "Loading predictions\u2026";
-  if (satDom.predCurrentList)  satDom.predCurrentList.innerHTML = "";
-  if (satDom.predUpcomingList) satDom.predUpcomingList.innerHTML = "";
-  try {
-    const resp = await fetch("/sat_passes");
-    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
-    const data = await resp.json() as SatellitePassResponse;
-    satPredSatCount = data.satellite_count || 0;
-    if (data.error) {
-      satPredData = [];
-      renderSatPredictions([], data.error);
-    } else {
-      satPredData = data.passes || [];
-      renderSatPredictions(getFilteredPredictions());
-    }
-  } catch (error: unknown) {
-    renderSatPredictions([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
-  }
-}
-
 // ── Navigate to map centered on satellite image bounds ──────────────
 satWindow.satShowOnMap = function (south: number, west: number, north: number, east: number) {
   if (typeof satWindow.enableMapSourceFilter === "function") {

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/satellite-predictions.ts

@@ -0,0 +1,290 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+import type { SatellitePass, SatellitePassResponse } from "./satellite-types";
+
+// --- Satellite pass predictions ---
+//
+// Its own page rather than a third view inside the weather-satellite decoder:
+// when a bird comes over is a planning question, and it was buried under
+// Digital modes beside decoders it has nothing to do with.
+
+interface PredictionsBridge {
+  clearSatPredictionDom?: () => void;
+  refreshSatPredictions?: () => void;
+}
+const predWindow = window as unknown as PredictionsBridge;
+
+// ── DOM references (cached once) ───────────────────────────────────
+const dom = {
+  page:            document.getElementById("tab-satellites"),
+  filter:          document.getElementById("sat-pred-filter") as HTMLInputElement | null,
+  minElevation:    document.getElementById("sat-pred-min-el") as HTMLSelectElement | null,
+  category:        document.getElementById("sat-pred-category") as HTMLSelectElement | null,
+  currentList:     document.getElementById("sat-pred-current-list"),
+  upcomingList:    document.getElementById("sat-pred-list"),
+  currentSection:  document.getElementById("sat-pred-current-section"),
+  upcomingSection: document.getElementById("sat-pred-upcoming-section"),
+  status:          document.getElementById("sat-pred-status"),
+};
+
+// ── State ───────────────────────────────────────────────────────────
+const PAGE_SIZE = 50;
+let predShowAll = false;
+let predData: SatellitePass[] = [];
+let predFilterText = "";
+let predMinEl = 0;
+let predCategory = "all";
+let predSatCount = 0;
+let predCountdownTimer: ReturnType<typeof setInterval> | null = null;
+
+/** The countdowns tick once a second, so they stop when nobody is looking. */
+function isPageVisible(): boolean {
+  return !!dom.page && dom.page.style.display !== "none";
+}
+
+// ── Predictions: helpers ────────────────────────────────────────────
+function azToCardinal(deg: number): string {
+  const dirs = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"];
+  return dirs[Math.round(deg / 45) % 8] ?? "N";
+}
+
+function formatPredTime(ms: number): string {
+  const d = new Date(ms);
+  const now = new Date();
+  const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
+  const day = d.getUTCDay() !== now.getUTCDay() ? `${dayNames[d.getUTCDay()] ?? ""} ` : "";
+  const hh = String(d.getUTCHours()).padStart(2, "0");
+  const mm = String(d.getUTCMinutes()).padStart(2, "0");
+  return `${day}${hh}:${mm}`;
+}
+
+function formatPredDuration(s: number): string {
+  if (s >= 60) return `${Math.round(s / 60)} min`;
+  return `${s}s`;
+}
+
+function formatCountdown(ms: number): string {
+  const totalSec = Math.max(0, Math.floor(ms / 1000));
+  const m = Math.floor(totalSec / 60);
+  const s = totalSec % 60;
+  return `${m}:${String(s).padStart(2, "0")}`;
+}
+
+function elevationClass(deg: number): string {
+  if (deg >= 45) return "sat-pred-el-high";
+  if (deg >= 10) return "sat-pred-el-mid";
+  return "sat-pred-el-low";
+}
+
+// ── Predictions: countdown timer management ─────────────────────────
+function stopCountdownTimer() {
+  if (predCountdownTimer) {
+    clearInterval(predCountdownTimer);
+    predCountdownTimer = null;
+  }
+}
+
+function startCountdownTimer(container: HTMLElement | null): void {
+  const countdownEls = container?.querySelectorAll<HTMLElement>(".sat-pred-col-countdown") ?? [];
+  if (countdownEls.length === 0) return;
+
+  predCountdownTimer = setInterval(() => {
+    if (!isPageVisible()) {
+      stopCountdownTimer();
+      return;
+    }
+    const n = Date.now();
+    let anyActive = false;
+    for (const el of countdownEls) {
+      const los = Number.parseInt(el.dataset.los ?? "0", 10);
+      const rem = los - n;
+      if (rem > 0) {
+        el.textContent = formatCountdown(rem);
+        anyActive = true;
+      } else {
+        el.textContent = "0:00";
+      }
+    }
+    if (!anyActive) {
+      stopCountdownTimer();
+      render(filtered());
+    }
+  }, 1000);
+}
+
+// ── Predictions: row builders ───────────────────────────────────────
+function buildCurrentPassRow(pass: SatellitePass, now: number): HTMLElement {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row-current";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
+  const remaining = Math.max(0, pass.los_ms - now);
+  row.innerHTML = [
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-time">${formatPredTime(pass.los_ms)}</span>`,
+    `<span class="sat-pred-col-countdown" data-los="${pass.los_ms}">${formatCountdown(remaining)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`,
+  ].join("");
+  return row;
+}
+
+function buildUpcomingPassRow(pass: SatellitePass): HTMLElement {
+  const row = document.createElement("div");
+  row.className = "sat-pred-row";
+  const dir = `${azToCardinal(pass.azimuth_aos_deg)} \u2192 ${azToCardinal(pass.azimuth_los_deg)}`;
+  row.innerHTML = [
+    `<span class="sat-pred-col-time">${formatPredTime(pass.aos_ms)}</span>`,
+    `<span class="sat-pred-col-sat">${pass.satellite}</span>`,
+    `<span class="sat-pred-col-el ${elevationClass(pass.max_elevation_deg)}">${pass.max_elevation_deg.toFixed(1)}\u00B0</span>`,
+    `<span class="sat-pred-col-dur">${formatPredDuration(pass.duration_s)}</span>`,
+    `<span class="sat-pred-col-dir">${dir}</span>`,
+  ].join("");
+  return row;
+}
+
+// ── Predictions: filter state ───────────────────────────────────────
+function filtered(): SatellitePass[] {
+  let items = predData;
+  if (predCategory !== "all") items = items.filter((p) => p.category === predCategory);
+  if (predMinEl > 0) items = items.filter((p) => p.max_elevation_deg >= predMinEl);
+  if (predFilterText) items = items.filter((p) => p.satellite.toUpperCase().includes(predFilterText));
+  return items;
+}
+
+function applyFilters() {
+  render(filtered());
+}
+
+const filterInput = dom.filter;
+filterInput?.addEventListener("input", () => {
+  predFilterText = filterInput.value.trim().toUpperCase();
+  applyFilters();
+});
+
+const minElevationSelect = dom.minElevation;
+minElevationSelect?.addEventListener("change", () => {
+  predMinEl = Number.parseInt(minElevationSelect.value, 10) || 0;
+  applyFilters();
+});
+
+const categorySelect = dom.category;
+categorySelect?.addEventListener("change", () => {
+  predCategory = categorySelect.value;
+  applyFilters();
+});
+
+// ── Predictions: main render ────────────────────────────────────────
+function render(passes: SatellitePass[], error?: string): void {
+  stopCountdownTimer();
+
+  if (error) {
+    if (dom.currentList)  dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection)   dom.currentSection.style.display = "none";
+    if (dom.upcomingSection)  dom.upcomingSection.style.display = "none";
+    if (dom.status)       dom.status.textContent = error;
+    return;
+  }
+
+  if (!Array.isArray(passes) || passes.length === 0) {
+    if (dom.currentList)  dom.currentList.innerHTML = "";
+    if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+    if (dom.currentSection)   dom.currentSection.style.display = "none";
+    if (dom.upcomingSection)  dom.upcomingSection.style.display = "none";
+    if (dom.status)       dom.status.textContent = "No passes found in the next 24 hours.";
+    return;
+  }
+
+  const now = Date.now();
+  const current = passes.filter((p) => p.aos_ms <= now && p.los_ms > now);
+  const upcoming = passes.filter((p) => p.aos_ms > now);
+
+  // ── Current passes ──
+  if (dom.currentSection) dom.currentSection.style.display = current.length > 0 ? "" : "none";
+  if (dom.currentList) {
+    if (current.length === 0) {
+      dom.currentList.innerHTML = "";
+    } else {
+      const frag = document.createDocumentFragment();
+      for (const pass of current) frag.appendChild(buildCurrentPassRow(pass, now));
+      dom.currentList.replaceChildren(frag);
+    }
+  }
+
+  // ── Upcoming passes ──
+  const upcomingLimit = predShowAll ? upcoming.length : PAGE_SIZE;
+  const visibleUpcoming = upcoming.slice(0, upcomingLimit);
+  const hiddenCount = upcoming.length - visibleUpcoming.length;
+  if (dom.upcomingSection) dom.upcomingSection.style.display = upcoming.length > 0 ? "" : "none";
+  if (dom.upcomingList) {
+    const frag = document.createDocumentFragment();
+    for (const pass of visibleUpcoming) frag.appendChild(buildUpcomingPassRow(pass));
+    if (hiddenCount > 0) {
+      const moreRow = document.createElement("div");
+      moreRow.className = "sat-pred-row";
+      moreRow.style.cursor = "pointer";
+      moreRow.style.textAlign = "center";
+      moreRow.innerHTML = `<span style="grid-column:1/-1;color:var(--accent);font-size:0.82rem;">Show ${hiddenCount} more passes\u2026</span>`;
+      moreRow.addEventListener("click", () => {
+        predShowAll = true;
+        render(filtered());
+      });
+      frag.appendChild(moreRow);
+    }
+    dom.upcomingList.replaceChildren(frag);
+  }
+
+  // ── Status ──
+  if (dom.status) {
+    let text = `${current.length} active \u00B7 ${upcoming.length} upcoming \u00B7 times in UTC`;
+    if (predSatCount > 0) text += ` \u00B7 ${predSatCount} satellites tracked`;
+    dom.status.textContent = text;
+  }
+
+  // ── Countdown timer ──
+  if (current.length > 0 && isPageVisible()) {
+    startCountdownTimer(dom.currentList);
+  }
+}
+
+// ── Predictions: data loading ───────────────────────────────────────
+async function load(): Promise<void> {
+  if (dom.status)       dom.status.textContent = "Loading predictions\u2026";
+  if (dom.currentList)  dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+  try {
+    const resp = await fetch("/sat_passes");
+    if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
+    const data = await resp.json() as SatellitePassResponse;
+    predSatCount = data.satellite_count || 0;
+    if (data.error) {
+      predData = [];
+      render([], data.error);
+    } else {
+      predData = data.passes || [];
+      render(filtered());
+    }
+  } catch (error: unknown) {
+    render([], `Failed to load predictions: ${error instanceof Error ? error.message : String(error)}`);
+  }
+}
+
+// ── Page lifecycle ──────────────────────────────────────────────────
+function clearPredictionDom(): void {
+  stopCountdownTimer();
+  if (dom.currentList)  dom.currentList.innerHTML = "";
+  if (dom.upcomingList) dom.upcomingList.innerHTML = "";
+}
+predWindow.clearSatPredictionDom = clearPredictionDom;
+
+/**
+ * Called by the router each time the Satellites page is opened, including the
+ * visit that imports this module — so loading is driven from one place only.
+ */
+predWindow.refreshSatPredictions = function () {
+  predShowAll = false;
+  void load();
+};

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/plugins/sstv.ts

@@ -0,0 +1,355 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// sstv.ts — SSTV decoder panel.
+//
+// Live view: decoder state, a canvas the picture fills row by row as it
+// arrives, and a card for the last one received. History view: a filterable
+// table of received pictures with thumbnails.
+//
+// Watching a picture build up is most of the appeal of the mode, so rows are
+// painted as they arrive rather than waiting for the frame to finish — a
+// transmission takes between 36 seconds and two minutes.
+
+import { hostCore } from "./host.js";
+
+import type { PluginRuntimeWindow } from "./runtime-contract.js";
+
+export {};
+
+interface SstvImage {
+  ts_ms?: number;
+  vis?: number;
+  mode?: string;
+  width?: number;
+  height?: number;
+  lines?: number;
+  complete?: boolean;
+  path?: string;
+  _tsMs?: number;
+  _ts?: string;
+}
+
+interface SstvProgress {
+  state?: string;
+  mode?: string;
+  width?: number;
+  height?: number;
+  line?: number;
+  line_data?: string;
+}
+
+interface SstvBridge {
+  getDecodeHistoryRetentionMs?: () => number;
+  trxScheduleUiFrameJob?: (key: string, job: () => void) => void;
+  takeSchedulerControlForDecoderDisable?: (button: HTMLElement) => Promise<unknown>;
+  syncSstvToggle?: (enabled: boolean) => void;
+}
+
+const sstvWindow = window as unknown as SstvBridge & PluginRuntimeWindow;
+
+const sstvDom = {
+  status: document.getElementById("sstv-status"),
+  liveView: document.getElementById("sstv-live-view"),
+  historyView: document.getElementById("sstv-history-view"),
+  liveContainer: document.getElementById("sstv-live-container"),
+  liveInfo: document.getElementById("sstv-live-info"),
+  liveCanvas: document.getElementById("sstv-live-canvas") as HTMLCanvasElement | null,
+  liveLatest: document.getElementById("sstv-live-latest"),
+  historyList: document.getElementById("sstv-history-list"),
+  historyCount: document.getElementById("sstv-history-count"),
+  filterInput: document.getElementById("sstv-filter") as HTMLInputElement | null,
+  sortSelect: document.getElementById("sstv-sort") as HTMLSelectElement | null,
+  toggleBtn: document.getElementById("sstv-decode-toggle-btn"),
+  clearBtn: document.getElementById("sstv-clear-btn"),
+  viewLiveBtn: document.getElementById("sstv-view-live"),
+  viewHistoryBtn: document.getElementById("sstv-view-history"),
+};
+
+const SSTV_MAX_IMAGES = 100;
+
+let sstvHistory: SstvImage[] = [];
+let liveCtx: CanvasRenderingContext2D | null = null;
+let liveMode = "";
+let liveHeight = 0;
+let liveRows = 0;
+let activeView: "live" | "history" = "live";
+let filterText = "";
+
+// ── Helpers ─────────────────────────────────────────────────────────
+
+function retentionMs(): number {
+  return sstvWindow.getDecodeHistoryRetentionMs?.() ?? 24 * 60 * 60 * 1000;
+}
+
+function pruneHistory() {
+  const cutoff = Date.now() - retentionMs();
+  sstvHistory = sstvHistory.filter((image) => (image._tsMs || 0) > cutoff);
+}
+
+function escapeHtml(value: unknown): string {
+  return String(value)
+    .replace(/&/g, "&amp;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;");
+}
+
+function scheduleUi(key: string, job: () => void): void {
+  if (typeof sstvWindow.trxScheduleUiFrameJob === "function") {
+    sstvWindow.trxScheduleUiFrameJob(key, job);
+    return;
+  }
+  job();
+}
+
+/** The URL the server serves a saved picture from, given its stored path. */
+function imageUrl(image: SstvImage): string | null {
+  if (!image.path) return null;
+  const filename = image.path.split(/[\\/]/).pop();
+  return filename ? `/sstv-images/${encodeURIComponent(filename)}` : null;
+}
+
+function decodeBase64(data: string): Uint8Array {
+  const binary = atob(data);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i += 1) bytes[i] = binary.charCodeAt(i);
+  return bytes;
+}
+
+// ── View switching ──────────────────────────────────────────────────
+
+function switchView(view: "live" | "history"): void {
+  activeView = view;
+  if (sstvDom.liveView) sstvDom.liveView.style.display = view === "live" ? "" : "none";
+  if (sstvDom.historyView) sstvDom.historyView.style.display = view === "history" ? "" : "none";
+  for (const button of [sstvDom.viewLiveBtn, sstvDom.viewHistoryBtn]) {
+    button?.classList.remove("sat-view-active");
+  }
+  if (view === "live") sstvDom.viewLiveBtn?.classList.add("sat-view-active");
+  else sstvDom.viewHistoryBtn?.classList.add("sat-view-active");
+  if (view === "history") renderHistoryTable();
+}
+
+sstvDom.viewLiveBtn?.addEventListener("click", () => { switchView("live"); });
+sstvDom.viewHistoryBtn?.addEventListener("click", () => { switchView("history"); });
+
+// ── Live canvas ─────────────────────────────────────────────────────
+
+/** Start a new picture: size the canvas to the mode and clear it. */
+function beginPicture(mode: string, width: number, height: number): void {
+  const canvas = sstvDom.liveCanvas;
+  if (!canvas || width <= 0 || height <= 0) return;
+  liveMode = mode;
+  liveHeight = height;
+  liveRows = 0;
+  canvas.width = width;
+  canvas.height = height;
+  liveCtx = canvas.getContext("2d");
+  if (!liveCtx) return;
+  // Mid-grey, not black: the rows below the one arriving have not been
+  // received, which is a different thing from having been received as black.
+  liveCtx.fillStyle = "#606060";
+  liveCtx.fillRect(0, 0, width, height);
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "";
+  updateLiveInfo();
+}
+
+function updateLiveInfo(): void {
+  if (!sstvDom.liveInfo) return;
+  const canvas = sstvDom.liveCanvas;
+  const size = canvas ? `${canvas.width}×${canvas.height}` : "";
+  sstvDom.liveInfo.textContent = liveMode
+    ? `${liveMode} · ${size} · line ${liveRows}${liveHeight ? ` of ${liveHeight}` : ""}`
+    : "";
+}
+
+/** Paint one row of RGB triples at its own line number. */
+function paintRow(line: number, rgb: Uint8Array): void {
+  const canvas = sstvDom.liveCanvas;
+  if (!liveCtx || !canvas) return;
+  const width = canvas.width;
+  if (line < 0 || line >= canvas.height || rgb.length < width * 3) return;
+  const row = liveCtx.createImageData(width, 1);
+  for (let x = 0; x < width; x += 1) {
+    row.data[x * 4] = rgb[x * 3] ?? 0;
+    row.data[x * 4 + 1] = rgb[x * 3 + 1] ?? 0;
+    row.data[x * 4 + 2] = rgb[x * 3 + 2] ?? 0;
+    row.data[x * 4 + 3] = 255;
+  }
+  liveCtx.putImageData(row, 0, line);
+  liveRows = Math.max(liveRows, line + 1);
+}
+
+// ── Server messages ─────────────────────────────────────────────────
+
+function onProgress(msg: SstvProgress): void {
+  if (msg.state) {
+    if (sstvDom.status) sstvDom.status.textContent = msg.state;
+    // A state update carries the geometry; a row update carries only the row.
+    beginPicture(msg.mode || "", msg.width || 0, msg.height || 0);
+    return;
+  }
+  if (typeof msg.line !== "number" || !msg.line_data) return;
+  const line = msg.line;
+  const rgb = decodeBase64(msg.line_data);
+  scheduleUi(`sstv-row-${line}`, () => {
+    paintRow(line, rgb);
+    updateLiveInfo();
+  });
+}
+
+function onImage(msg: SstvImage): void {
+  const image: SstvImage = { ...msg };
+  image._tsMs = typeof msg.ts_ms === "number" ? msg.ts_ms : Date.now();
+  image._ts = new Date(image._tsMs).toLocaleTimeString();
+  sstvHistory.push(image);
+  if (sstvHistory.length > SSTV_MAX_IMAGES) sstvHistory.shift();
+  pruneHistory();
+
+  if (sstvDom.status) {
+    sstvDom.status.textContent = image.complete
+      ? `Received ${image.mode ?? "picture"}`
+      : `Partial ${image.mode ?? "picture"} — ${image.lines ?? 0} lines`;
+  }
+  scheduleUi("sstv-latest", renderLatestCard);
+  if (activeView === "history") scheduleUi("sstv-history", renderHistoryTable);
+}
+
+// ── Rendering ───────────────────────────────────────────────────────
+
+function renderLatestCard(): void {
+  if (!sstvDom.liveLatest) return;
+  const latest = sstvHistory[sstvHistory.length - 1];
+  if (!latest) {
+    sstvDom.liveLatest.innerHTML = "";
+    return;
+  }
+  const url = imageUrl(latest);
+  const lines = `${latest.lines ?? 0}${latest.height ? ` of ${latest.height}` : ""} lines`;
+  const state = latest.complete ? "complete" : "partial";
+  sstvDom.liveLatest.innerHTML = `
+    <div class="sat-latest-card">
+      <div style="display:flex; align-items:baseline; gap:0.5rem; flex-wrap:wrap;">
+        <strong>${escapeHtml(latest.mode ?? "SSTV")}</strong>
+        <small style="color:var(--text-muted);">${escapeHtml(latest._ts ?? "")} · ${lines} · ${state}</small>
+      </div>
+      ${url
+        ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">
+             <img src="${escapeHtml(url)}" alt="Received ${escapeHtml(latest.mode ?? "SSTV")} picture"
+                  style="margin-top:0.4rem; width:100%; max-width:640px; image-rendering:pixelated;" />
+           </a>`
+        : ""}
+    </div>`;
+}
+
+function filteredHistory(): SstvImage[] {
+  const text = filterText.trim().toLowerCase();
+  const matching = text
+    ? sstvHistory.filter((image) => (image.mode ?? "").toLowerCase().includes(text))
+    : sstvHistory.slice();
+  const newestFirst = (sstvDom.sortSelect?.value ?? "newest") === "newest";
+  matching.sort((a, b) => (newestFirst ? 1 : -1) * ((b._tsMs ?? 0) - (a._tsMs ?? 0)));
+  return matching;
+}
+
+function renderHistoryTable(): void {
+  if (!sstvDom.historyList) return;
+  pruneHistory();
+  const rows = filteredHistory();
+  sstvDom.historyList.innerHTML = rows
+    .map((image) => {
+      const url = imageUrl(image);
+      const size = image.width && image.height ? `${image.width}×${image.height}` : "--";
+      const lines = image.complete
+        ? String(image.lines ?? 0)
+        : `${image.lines ?? 0} (partial)`;
+      return `<div class="sat-history-row">
+        <span class="sat-col-time">${escapeHtml(image._ts ?? "")}</span>
+        <span class="sat-col-type">${escapeHtml(image.mode ?? "--")}</span>
+        <span class="sat-col-sat">${escapeHtml(size)}</span>
+        <span class="sat-col-lines">${escapeHtml(lines)}</span>
+        <span class="sat-col-link">${url
+          ? `<a href="${escapeHtml(url)}" target="_blank" rel="noopener">View</a>`
+          : "--"}</span>
+      </div>`;
+    })
+    .join("");
+  if (sstvDom.historyCount) {
+    sstvDom.historyCount.textContent = rows.length
+      ? `${rows.length} picture${rows.length === 1 ? "" : "s"}`
+      : "No pictures yet";
+  }
+}
+
+sstvDom.filterInput?.addEventListener("input", () => {
+  filterText = sstvDom.filterInput?.value ?? "";
+  renderHistoryTable();
+});
+sstvDom.sortSelect?.addEventListener("change", () => { renderHistoryTable(); });
+
+// ── Decoder history plumbing ────────────────────────────────────────
+
+function restoreHistory(entries: unknown[]): void {
+  if (!Array.isArray(entries)) return;
+  for (const entry of entries) onImage(entry as SstvImage);
+}
+
+function resetHistoryView(): void {
+  sstvHistory = [];
+  liveRows = 0;
+  liveMode = "";
+  if (sstvDom.liveContainer) sstvDom.liveContainer.style.display = "none";
+  if (sstvDom.status) sstvDom.status.textContent = "Idle";
+  renderLatestCard();
+  renderHistoryTable();
+}
+
+// ── Controls ────────────────────────────────────────────────────────
+
+sstvWindow.syncSstvToggle = function syncSstvToggle(enabled: boolean) {
+  const button = sstvDom.toggleBtn as HTMLButtonElement | null;
+  if (!button) return;
+  button.textContent = enabled ? "Disable SSTV" : "Enable SSTV";
+  button.setAttribute("aria-pressed", String(enabled));
+  button.classList.toggle("is-active", enabled);
+};
+
+sstvDom.toggleBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      if (sstvDom.toggleBtn) {
+        await sstvWindow.takeSchedulerControlForDecoderDisable?.(sstvDom.toggleBtn);
+      }
+      await hostCore.postPath("/toggle_sstv_decode");
+    } catch (e) {
+      console.error("SSTV toggle failed", e);
+    }
+  })();
+});
+
+sstvDom.clearBtn?.addEventListener("click", () => {
+  void (async () => {
+    try {
+      await hostCore.postPath("/clear_sstv_decode");
+      resetHistoryView();
+    } catch (e) {
+      console.error("SSTV clear failed", e);
+    }
+  })();
+});
+
+renderLatestCard();
+
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv",
+  onMessage: onImage as (msg: unknown) => void,
+  restore: restoreHistory,
+  prune: renderHistoryTable,
+  reset: resetHistoryView,
+});
+sstvWindow.trxPluginRuntime.registerDecoder({
+  id: "sstv_progress",
+  onMessage: onProgress as (msg: unknown) => void,
+});

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/ui-core.ts

@@ -327,7 +327,9 @@ function elementById<T extends HTMLElement>(id: string): T {
 
   // Secondary controls, in the order they leave the bar when it gets tight.
   // Audio, record and the rig picker are the operating controls and stay.
-  const overflowOrder = [".operator-layout-picker", ".header-style-pick", "#theme-toggle"];
+  const overflowOrder = [
+    ".operator-layout-picker", ".header-style-pick", "#header-share-btn", "#theme-toggle",
+  ];
 
   // Anchored at paint time in fixed coordinates.  An absolutely positioned
   // dropdown is clipped by any scrolling ancestor and trapped inside the
@@ -497,7 +499,7 @@ function elementById<T extends HTMLElement>(id: string): T {
       if (restoreFocus) more.focus();
     };
     api.closeMobileOverlays = closeMore;
-    ["statistics", "recorder", "settings", "about"].forEach((tabName) => {
+    ["satellites", "statistics", "recorder", "settings", "about"].forEach((tabName) => {
       const source = nav.querySelector(`[data-tab="${tabName}"]`);
       if (!source) return;
       const item = document.createElement("button");
@@ -539,7 +541,7 @@ function elementById<T extends HTMLElement>(id: string): T {
     select.setAttribute("aria-label", "Decoder view");
     const groups: Array<[string, string[]]> = [
       ["Overview", ["overview"]], ["Marine & packet", ["ais", "vdes", "aprs", "hf-aprs"]],
-      ["Weak signal", ["cw", "ft8", "ft4", "ft2", "wspr"]], ["Broadcast & images", ["rds", "sat", "wefax"]],
+      ["Weak signal", ["cw", "ft8", "ft4", "ft2", "wspr"]], ["Broadcast & images", ["rds", "sat", "wefax", "sstv"]],
     ];
     groups.forEach(([label, ids]) => {
       const group = document.createElement("optgroup");

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/mobile-layout.mjs

@@ -0,0 +1,149 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// What a phone gets. A page that scrolls sideways is a page with something on
+// it nobody will find: the transmit controls spent this whole period laid out
+// at x=400 on a 390 px screen, off the side of a tray 354 px wide, reachable
+// only by a horizontal scroll with nothing to say it was there.
+
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+import { startBrowser, startWebFixture } from "./web-fixture.mjs";
+
+/* global document, getComputedStyle */
+
+const PHONES = [430, 390, 360];
+
+const fixture = await startWebFixture({ spectrum: true, tx: true });
+const { browser, page, runtimeErrors } = await startBrowser(chromium);
+
+try {
+  for (const width of PHONES) {
+    await page.setViewportSize({ width, height: 900 });
+    await page.goto(fixture.origin, { waitUntil: "domcontentloaded" });
+    await page.locator("#content").waitFor({ state: "visible" });
+    await page.waitForTimeout(1800);
+
+    const layout = await page.evaluate((viewport) => {
+      const box = (element) => element.getBoundingClientRect();
+      // Anything laid out past the right edge of the screen.
+      const past = [];
+      const walk = (element) => {
+        const rect = box(element);
+        if (rect.width > 0 && rect.right > viewport + 1) {
+          past.push(`${element.tagName.toLowerCase()}${element.id ? `#${element.id}` : ""}`);
+        }
+        for (const child of element.children) walk(child);
+      };
+      walk(document.getElementById("content"));
+      const tx = document.getElementById("tx-power-col");
+      return {
+        documentScroll: document.documentElement.scrollWidth,
+        past: past.slice(0, 6),
+        txRight: tx ? Math.round(box(tx).right) : null,
+        txVisible: tx ? getComputedStyle(tx).display !== "none" : false,
+        rigSelect: Math.round(box(document.getElementById("header-rig-switch-select")).width),
+      };
+    }, width);
+
+    assert.equal(layout.documentScroll, width,
+      `the page scrolls sideways at ${width}px (${layout.documentScroll}px wide)`);
+    assert.deepEqual(layout.past, [],
+      `laid out past the screen at ${width}px: ${layout.past.join(", ")}`);
+    if (layout.txVisible) {
+      assert.ok(layout.txRight <= width + 1,
+        `the transmit controls end at ${layout.txRight}px on a ${width}px screen`);
+    }
+    // The rig's name was taking 139px of a 338px bar and pushing everything
+    // else into the overflow menu.
+    assert.ok(layout.rigSelect <= 112,
+      `the rig picker is ${layout.rigSelect}px wide at ${width}px`);
+
+    // The bottom nav keeps its labels — that is what makes it navigation
+    // rather than five glyphs — and a label used to overflow its tab and run
+    // into the next one: "Bookmarks igital mode".
+    //
+    // What is asserted is that a label stays inside its own tab and, if it is
+    // too long for it, ends in an ellipsis. Not that it fits: how wide a
+    // platform draws a word varies by more than ten per cent, so "it fits"
+    // passes on the machine it was written on and fails on the next one —
+    // which is what a fixed font size did here.
+    const nav = await page.evaluate(() => {
+      const bar = document.querySelector(".tab-bar-nav");
+      return [...bar.querySelectorAll(".tab")]
+        .filter((tab) => tab.getBoundingClientRect().width > 0)
+        .map((tab) => {
+          const label = [...tab.querySelectorAll(".tab-label, .tab-label-short")]
+            .find((span) => getComputedStyle(span).display !== "none");
+          const style = label ? getComputedStyle(label) : null;
+          const labelBox = label?.getBoundingClientRect();
+          const tabBox = tab.getBoundingClientRect();
+          return {
+            text: (label?.textContent ?? "").trim(),
+            escapes: labelBox
+              ? labelBox.left < tabBox.left - 1 || labelBox.right > tabBox.right + 1
+              : false,
+            truncates: style?.textOverflow === "ellipsis" && style?.overflow !== "visible",
+            empty: !labelBox || labelBox.width < 1,
+          };
+        });
+    });
+    assert.ok(nav.length >= 4, `the bottom nav has ${nav.length} destinations at ${width}px`);
+    const escaped = nav.filter((tab) => tab.escapes).map((tab) => tab.text);
+    assert.deepEqual(escaped, [],
+      `labels overflowing their tab at ${width}px: ${escaped.join(", ")}`);
+    const untruncatable = nav.filter((tab) => !tab.truncates).map((tab) => tab.text);
+    assert.deepEqual(untruncatable, [],
+      `labels that would be cut rather than ellipsised at ${width}px: ${untruncatable.join(", ")}`);
+    const blank = nav.filter((tab) => tab.empty).map((tab, index) => tab.text || `#${index}`);
+    assert.deepEqual(blank, [], `destinations with no label at ${width}px: ${blank.join(", ")}`);
+  }
+
+  // A tab whose visible label is shortened for the nav still has to say what
+  // it is to anything that reads the page rather than looks at it.
+  const named = await page.evaluate(() => {
+    const tab = document.querySelector('.tab[data-tab="digital-modes"]');
+    const short = tab.querySelector(".tab-label-short");
+    return {
+      label: tab.getAttribute("aria-label"),
+      shortHidden: short?.getAttribute("aria-hidden"),
+    };
+  });
+  assert.equal(named.label, "Digital modes", "the shortened tab lost its full name");
+  assert.equal(named.shortHidden, "true", "the short label is read out as well as shown");
+
+  // Hiding the map's filters leaves the bar, and the bar has to still be
+  // there to bring them back — it carries the only button that does.
+  await page.setViewportSize({ width: 1400, height: 900 });
+  await page.goto(`${fixture.origin}/map`, { waitUntil: "domcontentloaded" });
+  await page.locator("#aprs-map .leaflet-pane").first().waitFor({ state: "attached" });
+  await page.waitForTimeout(1200);
+  await page.locator("#map-overlay-toggle-btn").click();
+  await page.waitForTimeout(400);
+  const collapsed = await page.evaluate(() => {
+    const panel = document.querySelector(".map-overlay-panel");
+    const style = getComputedStyle(panel);
+    const rect = panel.getBoundingClientRect();
+    const button = document.getElementById("map-overlay-toggle-btn").getBoundingClientRect();
+    return {
+      width: Math.round(rect.width),
+      height: Math.round(rect.height),
+      opacity: Number(style.opacity),
+      visibility: style.visibility,
+      display: style.display,
+      buttonWidth: Math.round(button.width),
+    };
+  });
+  assert.ok(collapsed.width > 0 && collapsed.height > 0,
+    `the collapsed bar measures ${collapsed.width}x${collapsed.height}`);
+  assert.equal(collapsed.visibility, "visible", "the collapsed bar is not visible");
+  assert.notEqual(collapsed.display, "none", "the collapsed bar is display:none");
+  assert.equal(collapsed.opacity, 1, `the collapsed bar is at opacity ${collapsed.opacity}`);
+  assert.ok(collapsed.buttonWidth > 0, "Show Filters has no size to click");
+
+  assert.deepEqual(runtimeErrors, []);
+} finally {
+  await browser.close();
+  await fixture.close();
+}

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/navigation-routes.test.mjs

@@ -17,7 +17,8 @@ async function loadRoutes(window) {
     write: false,
   });
   const module = { exports: {} };
-  vm.runInNewContext(result.outputFiles[0].text, { module, exports: module.exports, window });
+  // The sandbox is bare; the browser globals the module actually uses go in.
+  vm.runInNewContext(result.outputFiles[0].text, { module, exports: module.exports, window, URLSearchParams });
   return module.exports;
 }
 
@@ -38,3 +39,55 @@ test("all top-level tabs have stable round-trip routes", async () => {
   assert.equal(calls[0][0], "push");
   assert.equal(calls[0][3], "/statistics?rig=one#panel");
 });
+
+// A tune link is what one operator sends another: it has to survive being
+// typed by hand, and it has to come back out as the frequency that went in.
+test("tune links parse the frequencies people write", async () => {
+  const routes = await loadRoutes({ location: { pathname: "/", search: "", hash: "" }, history: {} });
+  for (const [text, hz] of [
+    ["14074000", 14_074_000], ["14074000hz", 14_074_000],
+    ["7074k", 7_074_000], ["14.074M", 14_074_000], ["1.2G", 1_200_000_000],
+    ["  145500k  ", 145_500_000],
+  ]) {
+    assert.equal(routes.parseFrequencyParam(text), hz, `${text} did not read as ${hz} Hz`);
+  }
+  for (const bad of ["", "  ", "abc", "-7074", "0", "14,074", "1e6", null, undefined]) {
+    assert.equal(routes.parseFrequencyParam(bad), null, `${bad} was read as a frequency`);
+  }
+});
+
+test("tune links carry rig, frequency, mode and bandwidth", async () => {
+  const routes = await loadRoutes({ location: { pathname: "/", search: "", hash: "" }, history: {} });
+  assert.deepEqual({ ...routes.parseTuneLink("?rig=sdr&f=14.074M&mode=usb&bw=3k") }, {
+    rig: "sdr", freqHz: 14_074_000, mode: "USB", bandwidthHz: 3000,
+  });
+  // A link with nothing to say must not tune anything.
+  assert.deepEqual({ ...routes.parseTuneLink("?tab=map") }, {
+    rig: null, freqHz: null, mode: null, bandwidthHz: null,
+  });
+  // Junk in a parameter is not a frequency, and must not become one.
+  assert.deepEqual({ ...routes.parseTuneLink("?f=&mode=NOTAMODE&bw=wide") }, {
+    rig: null, freqHz: null, mode: null, bandwidthHz: null,
+  });
+});
+
+test("writing a tune link canonicalises it and leaves other parameters alone", async () => {
+  const routes = await loadRoutes({ location: { pathname: "/", search: "", hash: "" }, history: {} });
+  const search = routes.tuneLinkSearch("?theme=dark&f=7074k", {
+    rig: "sdr", freqHz: 14_074_000.4, mode: "usb", bandwidthHz: 3000,
+  });
+  const params = new URLSearchParams(search);
+  assert.equal(params.get("theme"), "dark", "an unrelated parameter was dropped");
+  assert.equal(params.get("f"), "14074000", "the frequency was not written as whole Hz");
+  assert.equal(params.get("mode"), "USB");
+  assert.equal(params.get("bw"), "3000");
+  assert.equal(params.get("rig"), "sdr");
+  // Round trip: what was written reads back as what went in.
+  assert.deepEqual({ ...routes.parseTuneLink(search) }, {
+    rig: "sdr", freqHz: 14_074_000, mode: "USB", bandwidthHz: 3000,
+  });
+  // Nothing known yet means no stale tune parameters left behind.
+  const cleared = routes.tuneLinkSearch(search, { rig: null, freqHz: null, mode: null, bandwidthHz: null });
+  assert.equal(cleared, "?theme=dark");
+  assert.equal(routes.tuneLinkSearch("", { rig: null, freqHz: null, mode: null, bandwidthHz: null }), "");
+});

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/satellite-predictions.mjs

@@ -0,0 +1,122 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Pass predictions used to be a third view inside the weather-satellite
+// decoder, under Digital modes — a planning tool filed with the decoders it has
+// nothing to do with. It is its own page now, so what this guards is that the
+// page exists at its own address, renders passes, and that the decoder card no
+// longer offers the view it gave up.
+
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+import { startBrowser, startWebFixture } from "./web-fixture.mjs";
+
+/* global document, window, getComputedStyle */
+
+const HOUR = 3_600_000;
+const now = Date.now();
+const satPasses = {
+  satellite_count: 2,
+  passes: [
+    // In progress right now, so the page has a countdown to run.
+    {
+      satellite: "NOAA 19", category: "weather",
+      aos_ms: now - 4 * 60_000, los_ms: now + 6 * 60_000,
+      max_elevation_deg: 62.4, duration_s: 600,
+      azimuth_aos_deg: 10, azimuth_los_deg: 190,
+    },
+    {
+      satellite: "ISS", category: "amateur",
+      aos_ms: now + 2 * HOUR, los_ms: now + 2 * HOUR + 480_000,
+      max_elevation_deg: 18.2, duration_s: 480,
+      azimuth_aos_deg: 200, azimuth_los_deg: 20,
+    },
+  ],
+};
+
+const fixture = await startWebFixture({ satPasses });
+const { browser, page, runtimeErrors } = await startBrowser(chromium);
+
+try {
+  await page.setViewportSize({ width: 1500, height: 950 });
+
+  // The page is reachable at its own address, not through a decoder sub-view.
+  // #content is the radio panel on the main tab, so the readiness signal for a
+  // deep link is the destination panel itself.
+  await page.goto(`${fixture.origin}/satellites`, { waitUntil: "domcontentloaded" });
+  await page.locator("#tab-satellites").waitFor({ state: "visible" });
+
+  await page.waitForFunction(
+    () => (document.getElementById("sat-pred-list")?.childElementCount ?? 0) > 0,
+    null,
+    { timeout: 5000 },
+  );
+
+  const rendered = await page.evaluate(() => ({
+    current: document.getElementById("sat-pred-current-list").textContent,
+    upcoming: document.getElementById("sat-pred-list").textContent,
+    status: document.getElementById("sat-pred-status").textContent,
+    activeTab: document.querySelector(".tab-bar .tab.active")?.dataset.tab,
+  }));
+  assert.match(rendered.current, /NOAA 19/, `current passes read "${rendered.current}"`);
+  assert.match(rendered.upcoming, /ISS/, `upcoming passes read "${rendered.upcoming}"`);
+  assert.match(rendered.status, /1 active/, `status reads "${rendered.status}"`);
+  assert.equal(rendered.activeTab, "satellites", "the Satellites tab is the active one");
+
+  // A pass in progress counts down, so the seconds have to move on their own.
+  const firstTick = await page.evaluate(
+    () => document.querySelector(".sat-pred-col-countdown[data-los]")?.textContent);
+  await page.waitForTimeout(1600);
+  const secondTick = await page.evaluate(
+    () => document.querySelector(".sat-pred-col-countdown[data-los]")?.textContent);
+  assert.notEqual(firstTick, secondTick, `the countdown sat at ${firstTick}`);
+
+  // Leaving stops the countdown rather than leaving a timer running behind a
+  // hidden page.
+  await page.evaluate(() => { window.navigateToTab("main"); });
+  await page.waitForTimeout(300);
+  const afterLeaving = await page.evaluate(() => ({
+    visible: document.getElementById("tab-satellites").style.display,
+    rows: document.getElementById("sat-pred-current-list").childElementCount,
+  }));
+  assert.equal(afterLeaving.visible, "none", "the page stayed on screen after navigating away");
+  assert.equal(afterLeaving.rows, 0, "the countdown rows outlived the page");
+
+  // Coming back reloads rather than showing whatever was there before.
+  await page.evaluate(() => { window.navigateToTab("satellites"); });
+  await page.waitForFunction(
+    () => (document.getElementById("sat-pred-list")?.childElementCount ?? 0) > 0,
+    null,
+    { timeout: 5000 },
+  );
+
+  // The page is an occasional destination, so it lives behind Tools rather than
+  // taking a slot in the operating strip — the same treatment Statistics,
+  // Recorder, Settings and About get.
+  const nav = await page.evaluate(() => ({
+    inStrip: getComputedStyle(document.querySelector('.tab-bar-nav .tab[data-tab="satellites"]')).display,
+    inTools: !!document.querySelector('#mobile-more-menu [data-navigate-tab="satellites"]'),
+  }));
+  assert.equal(nav.inStrip, "none", "Satellites took a slot in the operating strip");
+  assert.ok(nav.inTools, "Satellites is not reachable from Tools");
+
+  // The decoder card keeps Live and History, and no longer offers Predictions.
+  await page.goto(`${fixture.origin}/digital-modes`, { waitUntil: "domcontentloaded" });
+  await page.locator("#tab-digital-modes").waitFor({ state: "visible" });
+  const satCard = await page.evaluate(() => ({
+    predictionsButton: !!document.getElementById("sat-view-predictions"),
+    predictionsView: !!document.getElementById("sat-predictions-view"),
+    live: !!document.getElementById("sat-view-live"),
+    history: !!document.getElementById("sat-view-history"),
+  }));
+  assert.equal(satCard.predictionsButton, false, "the decoder card still offers Predictions");
+  assert.equal(satCard.predictionsView, false, "the old predictions view is still in the page");
+  assert.ok(satCard.live && satCard.history, "the decoder card lost Live/History");
+
+  assert.deepEqual(runtimeErrors, [], "the page threw while showing predictions");
+  console.log("satellite predictions page tests passed");
+} finally {
+  await browser.close();
+  await fixture.close();
+}

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/spectrum-layout.mjs

@@ -196,6 +196,62 @@ try {
   await fixture.close();
 }
 
+// The strip of controls under the plot. Its two clusters — the receiver's
+// bandwidth and the display's levels — used to size themselves independently:
+// four control heights on one line, and between about 1100 and 1400 px the
+// left cluster wrapped to two lines while the right one did not, leaving the
+// two at heights that matched neither each other nor anything else.
+const stripFixture = await startWebFixture({ spectrum: true });
+const strip = await startBrowser(chromium);
+try {
+  for (const width of [1600, 1200, 900]) {
+    await strip.page.setViewportSize({ width, height: 950 });
+    await strip.page.goto(stripFixture.origin, { waitUntil: "domcontentloaded" });
+    await strip.page.locator("#spectrum-panel").waitFor({ state: "visible" });
+    await strip.page.waitForTimeout(1600);
+
+    const measured = await strip.page.evaluate(() => {
+      const controls = document.getElementById("spectrum-controls");
+      const box = (element) => element.getBoundingClientRect();
+      const clusters = [...controls.children]
+        .filter((child) => child.id)
+        .map((child) => ({ id: child.id, top: Math.round(box(child).top) }));
+      const parts = [...controls.querySelectorAll(".spectrum-field, .spectrum-btn")];
+      return {
+        heights: [...new Set(parts.map((part) => Math.round(box(part).height)))],
+        count: parts.length,
+        clusters,
+        // Rows are lines of the strip: clusters sharing a top are on one line.
+        lines: new Set(clusters.map((cluster) => cluster.top)).size,
+        overflows: controls.scrollWidth > controls.clientWidth + 1,
+        insidePanel: box(controls).right
+          <= box(document.getElementById("spectrum-panel")).right + 1,
+      };
+    });
+
+    // Five fields and four buttons: bandwidth, Set, Auto BW, Sweet-spot, peak
+    // hold, floor, range, Auto, contrast.
+    assert.equal(measured.count, 9, `the strip has ${measured.count} controls at ${width}px`);
+    assert.deepEqual(measured.heights.length, 1,
+      `controls are ${measured.heights.join(", ")}px tall at ${width}px`);
+    assert.equal(measured.overflows, false, `the strip overflows at ${width}px`);
+    assert.equal(measured.insidePanel, true, `the strip runs past the plot at ${width}px`);
+
+    // Either both clusters share a line, or each has one to itself. What must
+    // never happen is one cluster floating against the middle of the other.
+    const tops = measured.clusters.map((cluster) => cluster.top);
+    assert.ok(
+      measured.lines === 1 || measured.lines === measured.clusters.length,
+      `clusters sit at ${tops.join(", ")} at ${width}px`,
+    );
+  }
+
+  assert.deepEqual(strip.runtimeErrors, []);
+} finally {
+  await strip.browser.close();
+  await stripFixture.close();
+}
+
 // The band plan is fetched once at startup, which can land before the session
 // exists. It used to fail silently and never retry, so the allocations only
 // turned up if the operator reloaded the page by hand.

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/sstv.test.mjs

@@ -0,0 +1,186 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// The SSTV panel: a picture arriving row by row, and what is kept once it has.
+// Watching the image build up is the point of the mode, so rows have to reach
+// the canvas as they arrive rather than at the end of a two-minute frame.
+
+import assert from "node:assert/strict";
+import test from "node:test";
+import vm from "node:vm";
+import { bundleEntry } from "./bundle-entry.mjs";
+import { createHost } from "./host-fixture.mjs";
+
+/** A DOM stub with only what the plugin reaches for. */
+function makeElement(id) {
+  const listeners = new Map();
+  return {
+    id,
+    textContent: "",
+    innerHTML: "",
+    value: "",
+    style: {},
+    attributes: {},
+    classList: {
+      classes: new Set(),
+      add(name) { this.classes.add(name); },
+      remove(name) { this.classes.delete(name); },
+      toggle(name, on) { if (on) this.classes.add(name); else this.classes.delete(name); },
+      contains(name) { return this.classes.has(name); },
+    },
+    addEventListener(type, handler) { listeners.set(type, handler); },
+    setAttribute(name, value) { this.attributes[name] = String(value); },
+    getAttribute(name) { return this.attributes[name] ?? null; },
+    click() { listeners.get("click")?.(); },
+    fire(type, event) { listeners.get(type)?.(event); },
+  };
+}
+
+function makeCanvas(id) {
+  const element = makeElement(id);
+  element.width = 0;
+  element.height = 0;
+  const painted = [];
+  const fills = [];
+  element.painted = painted;
+  element.fills = fills;
+  element.getContext = () => ({
+    fillStyle: "",
+    fillRect: (...args) => { fills.push(args); },
+    createImageData: (width, height) => ({
+      width, height, data: new Uint8ClampedArray(width * height * 4),
+    }),
+    putImageData: (image, x, y) => { painted.push({ x, y, data: image.data }); },
+  });
+  return element;
+}
+
+async function loadPanel() {
+  const elements = new Map();
+  const element = (id) => {
+    if (!elements.has(id)) {
+      elements.set(id, id.endsWith("canvas") ? makeCanvas(id) : makeElement(id));
+    }
+    return elements.get(id);
+  };
+  // Touch every id the panel defines, so the plugin caches real stubs.
+  for (const id of [
+    "sstv-status", "sstv-live-view", "sstv-history-view", "sstv-live-container",
+    "sstv-live-info", "sstv-live-canvas", "sstv-live-latest", "sstv-history-list",
+    "sstv-history-count", "sstv-filter", "sstv-sort", "sstv-decode-toggle-btn",
+    "sstv-clear-btn", "sstv-view-live", "sstv-view-history",
+  ]) element(id);
+
+  const window = { ...createHost() };
+  const context = vm.createContext({
+    window,
+    document: { getElementById: (id) => elements.get(id) ?? null },
+    atob: (data) => Buffer.from(data, "base64").toString("binary"),
+    Date, Number, String, Math, Set, Uint8Array, Uint8ClampedArray, JSON, console,
+  });
+  const runtime = await bundleEntry(new URL("../src/plugin-runtime.ts", import.meta.url));
+  const source = await bundleEntry(new URL("../src/plugins/sstv.ts", import.meta.url));
+  new vm.Script(runtime).runInContext(context);
+  new vm.Script(source).runInContext(context);
+  return { window, runtime: window.trxPluginRuntime, element };
+}
+
+/** One row of RGB triples, base64 as the server sends it. */
+function rowData(width, [r, g, b]) {
+  const bytes = new Uint8Array(width * 3);
+  for (let x = 0; x < width; x += 1) {
+    bytes[x * 3] = r;
+    bytes[x * 3 + 1] = g;
+    bytes[x * 3 + 2] = b;
+  }
+  return Buffer.from(bytes).toString("base64");
+}
+
+test("a picture arriving paints its rows as they come", async () => {
+  const { runtime, element } = await loadPanel();
+
+  // The header names the mode and the geometry; the canvas takes both.
+  runtime.dispatch("sstv_progress", {
+    state: "Receiving Martin M1", mode: "Martin M1", width: 320, height: 256, line: 0,
+  });
+  const canvas = element("sstv-live-canvas");
+  assert.equal(canvas.width, 320, "the canvas did not take the mode's width");
+  assert.equal(canvas.height, 256, "the canvas did not take the mode's height");
+  assert.equal(element("sstv-live-container").style.display, "",
+    "the live view stayed hidden while a picture was arriving");
+  assert.match(element("sstv-status").textContent, /Martin M1/);
+
+  // Rows land at the line number they carry, not in arrival order: a decoder
+  // that painted them in sequence would shear a picture with a dropped line.
+  runtime.dispatch("sstv_progress", { line: 4, line_data: rowData(320, [255, 0, 0]) });
+  runtime.dispatch("sstv_progress", { line: 2, line_data: rowData(320, [0, 0, 255]) });
+  assert.deepEqual(canvas.painted.map((p) => p.y), [4, 2],
+    `rows painted at ${canvas.painted.map((p) => p.y).join(",")}`);
+  assert.deepEqual([...canvas.painted[0].data.slice(0, 4)], [255, 0, 0, 255], "row 4 is not red");
+  assert.deepEqual([...canvas.painted[1].data.slice(0, 4)], [0, 0, 255, 255], "row 2 is not blue");
+  assert.match(element("sstv-live-info").textContent, /Martin M1/);
+});
+
+test("a received picture is kept, shown, and linked by file name alone", async () => {
+  const { runtime, element } = await loadPanel();
+
+  // Recent, not a fixed date: the panel drops anything older than the history
+  // retention window, so a picture stamped with the day the test was written
+  // passes until that day is a day ago.
+  runtime.dispatch("sstv", {
+    ts_ms: Date.now() - 60_000,
+    vis: 44, mode: "Martin M1", width: 320, height: 256, lines: 256, complete: true,
+    path: "/home/op/.cache/trx-rs/sstv/SSTV_20260805T120000Z_14230000_Martin-M1.png",
+  });
+
+  const latest = element("sstv-live-latest").innerHTML;
+  assert.match(latest, /Martin M1/);
+  assert.match(latest, /complete/);
+  // The server serves pictures by file name; the path it stored is its own.
+  assert.match(latest, /\/sstv-images\/SSTV_20260805T120000Z_14230000_Martin-M1\.png/);
+  assert.doesNotMatch(latest, /home\/op/, "the server's filesystem path reached the page");
+
+  element("sstv-view-history").click();
+  const history = element("sstv-history-list").innerHTML;
+  assert.match(history, /Martin M1/);
+  assert.match(history, /320×256/);
+  assert.match(element("sstv-history-count").textContent, /1 picture/);
+});
+
+test("a picture cut short is kept, and says so", async () => {
+  const { runtime, element } = await loadPanel();
+
+  runtime.dispatch("sstv", {
+    ts_ms: Date.now(), vis: 60, mode: "Scottie S1", width: 320, height: 256,
+    lines: 91, complete: false, path: "/cache/SSTV_x_Scottie-S1.png",
+  });
+
+  assert.match(element("sstv-status").textContent, /Partial/);
+  element("sstv-view-history").click();
+  assert.match(element("sstv-history-list").innerHTML, /91 \(partial\)/);
+});
+
+test("clearing empties the panel", async () => {
+  const { runtime, element } = await loadPanel();
+  runtime.dispatch("sstv", { ts_ms: Date.now(), mode: "PD120", lines: 496, complete: true });
+  assert.match(element("sstv-live-latest").innerHTML, /PD120/);
+
+  runtime.reset("sstv");
+  assert.equal(element("sstv-live-latest").innerHTML, "");
+  assert.equal(element("sstv-status").textContent, "Idle");
+  assert.equal(element("sstv-live-container").style.display, "none");
+});
+
+test("the toggle button follows the rig state", async () => {
+  const { window, element } = await loadPanel();
+  const button = element("sstv-decode-toggle-btn");
+
+  window.syncSstvToggle(true);
+  assert.equal(button.textContent, "Disable SSTV");
+  assert.equal(button.getAttribute("aria-pressed"), "true");
+
+  window.syncSstvToggle(false);
+  assert.equal(button.textContent, "Enable SSTV");
+  assert.equal(button.getAttribute("aria-pressed"), "false");
+});

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/tune-links.mjs

@@ -0,0 +1,102 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// A link is how one operator tells another where to listen. Opening one has to
+// put the radio there, and the address bar has to keep up with the dial after
+// that — a link that goes stale the moment someone tunes is worse than none,
+// because it looks like it works.
+
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+import { startBrowser, startWebFixture } from "./web-fixture.mjs";
+
+/* global document, window */
+
+const LINK_HZ = 14_074_000;
+const LINK_BW = 2_800;
+const TUNED_HZ = 7_040_000;
+
+const fixture = await startWebFixture({ spectrum: true });
+const { browser, page, runtimeErrors } = await startBrowser(chromium);
+
+const dial = () => page.evaluate(() => ({
+  freqHz: window.lastFreqHz,
+  mode: document.getElementById("mode").value,
+  search: window.location.search,
+  path: window.location.pathname,
+}));
+
+try {
+  await page.setViewportSize({ width: 1500, height: 950 });
+
+  // Opening the link tunes the radio: frequency, mode and bandwidth.
+  await page.goto(`${fixture.origin}/?f=14.074M&mode=USB&bw=${LINK_BW}`, { waitUntil: "domcontentloaded" });
+  await page.locator("#content").waitFor({ state: "visible" });
+  await page.waitForTimeout(2500);
+
+  const opened = await dial();
+  assert.equal(opened.freqHz, LINK_HZ, `the link left the radio on ${opened.freqHz} Hz`);
+  assert.equal(opened.mode, "USB", `the link left the radio in ${opened.mode}`);
+  const bandwidth = await page.evaluate(() => window.currentBandwidthHz);
+  assert.equal(bandwidth, LINK_BW, `the link left the bandwidth at ${bandwidth} Hz`);
+
+  // Hand-written frequencies are canonicalised in place, so what the operator
+  // copies back out is the same link in the form the app writes.
+  const params = new URLSearchParams(opened.search);
+  assert.equal(params.get("f"), String(LINK_HZ), `the URL kept "${params.get("f")}"`);
+  assert.equal(params.get("mode"), "USB");
+
+  // Tuning by hand rewrites the link. This is the part that makes the address
+  // bar shareable at any moment rather than only at load.
+  await page.locator("#freq").fill("7.040M");
+  await page.locator("#freq").press("Enter");
+  await page.waitForTimeout(1500);
+  const tuned = await dial();
+  assert.equal(tuned.freqHz, TUNED_HZ, `tuning landed on ${tuned.freqHz} Hz`);
+  assert.equal(new URLSearchParams(tuned.search).get("f"), String(TUNED_HZ),
+    `the URL still reads "${tuned.search}" after tuning`);
+
+  // Tuning is not navigation: a swept dial must not bury the back button.
+  const historyLength = await page.evaluate(() => window.history.length);
+  await page.locator("#freq").fill("7.100M");
+  await page.locator("#freq").press("Enter");
+  await page.waitForTimeout(1200);
+  assert.equal(await page.evaluate(() => window.history.length), historyLength,
+    "tuning pushed a history entry instead of replacing one");
+
+  // Moving between tabs keeps the tune parameters: the path changes, the link
+  // does not stop being a link.
+  await page.locator('.tab[data-tab="map"]').click();
+  await page.waitForTimeout(800);
+  const onMap = await dial();
+  assert.equal(onMap.path, "/map", `the map tab landed on ${onMap.path}`);
+  assert.equal(new URLSearchParams(onMap.search).get("f"), "7100000",
+    `the map tab dropped the tune parameters: "${onMap.search}"`);
+
+  // A link naming a rig selects it before applying the rest.
+  await page.goto(`${fixture.origin}/?rig=rig-b&f=${TUNED_HZ}&mode=CW`, { waitUntil: "domcontentloaded" });
+  await page.locator("#content").waitFor({ state: "visible" });
+  await page.waitForTimeout(2500);
+  const switched = await page.evaluate(() => ({
+    rig: document.getElementById("header-rig-switch-select")?.value ?? null,
+    selected: window.location.search,
+    mode: document.getElementById("mode").value,
+  }));
+  assert.equal(switched.rig, "rig-b", `the link left the client on rig "${switched.rig}"`);
+  assert.equal(switched.mode, "CW", `the link left the radio in ${switched.mode}`);
+
+  // A link with nothing to say tunes nothing, and the address bar fills in
+  // with where the radio already is.
+  await page.goto(fixture.origin, { waitUntil: "domcontentloaded" });
+  await page.locator("#content").waitFor({ state: "visible" });
+  await page.waitForTimeout(2000);
+  const bare = await dial();
+  assert.equal(new URLSearchParams(bare.search).get("f"), String(bare.freqHz),
+    `a bare load wrote "${bare.search}" for a radio on ${bare.freqHz} Hz`);
+
+  assert.deepEqual(runtimeErrors, []);
+} finally {
+  await browser.close();
+  await fixture.close();
+}

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/web-fixture.mjs

@@ -29,6 +29,7 @@ const DECODER_REGISTRY = [
   { id: "cw", label: "CW", activation: "toggle", active_modes: ["CW", "CWR"] },
   { id: "sat", label: "SAT", activation: "toggle", active_modes: ["FM"] },
   { id: "wefax", label: "WEFAX", activation: "toggle", active_modes: ["USB"] },
+  { id: "sstv", label: "SSTV", activation: "toggle", active_modes: ["USB", "FM"] },
   { id: "ais", label: "AIS", activation: "toggle", active_modes: ["FM"] },
   { id: "aprs", label: "APRS", activation: "toggle", active_modes: ["FM"] },
   { id: "hf-aprs", label: "HF APRS", activation: "toggle", active_modes: ["USB"] },
@@ -104,7 +105,7 @@ function encodeCbor(value) {
   return Buffer.concat(chunks);
 }
 
-const HISTORY_GROUPS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax"];
+const HISTORY_GROUPS = ["ais", "vdes", "aprs", "hf_aprs", "cw", "ft8", "ft4", "ft2", "wspr", "wefax", "sstv"];
 
 function assetPath(urlPath) {
   // Every tab route has its own index handler on the server (see api/assets.rs),
@@ -134,6 +135,7 @@ export async function startWebFixture({
   bandplan = {},
   bandplanEnabled = false,
   bandplanUnauthorizedFirst = false,
+  satPasses = null,
 } = {}) {
   const rigItems = ["rig-a", "rig-b"].map((remote) => ({
     remote,
@@ -203,6 +205,7 @@ export async function startWebFixture({
     wspr_decode_enabled: false,
     lrpt_decode_enabled: false,
     wefax_decode_enabled: false,
+    sstv_decode_enabled: false,
     recorder_enabled: false,
     clients: 1,
     rigctl_clients: 0,
@@ -228,6 +231,7 @@ export async function startWebFixture({
     ["/bandplan.json", bandplan],
     ["/api/recorder/status", []],
     ["/api/recorder/files", []],
+    ["/sat_passes", satPasses ?? { satellite_count: 0, passes: [] }],
   ]);
 
   // Flat i8 bins: the shape does not matter, only that frames arrive so the
@@ -249,6 +253,24 @@ export async function startWebFixture({
       response.writeHead(200).end();
       return;
     }
+    if (url.pathname === "/set_freq") {
+      const hz = Number(url.searchParams.get("hz"));
+      if (Number.isFinite(hz) && hz > 0) status.status.freq = { hz: Math.round(hz) };
+      response.writeHead(200).end();
+      return;
+    }
+    if (url.pathname === "/set_mode") {
+      const next = (url.searchParams.get("mode") || "").toUpperCase();
+      if (next) status.status.mode = next;
+      response.writeHead(200).end();
+      return;
+    }
+    if (url.pathname === "/set_bandwidth") {
+      const hz = Number(url.searchParams.get("hz"));
+      if (Number.isFinite(hz) && hz > 0 && status.filter) status.filter.bandwidth_hz = Math.round(hz);
+      response.writeHead(200).end();
+      return;
+    }
     if (url.pathname === "/select_rig" && request.method === "POST") {
       const remote = url.searchParams.get("remote");
       if (remote) {
@@ -347,9 +369,11 @@ export async function startWebFixture({
       });
       // Varying, as a real one is: the client skips a frame identical to the
       // last, so a repeated payload exercises none of the state-update path.
+      // The variation rides on the S-meter rather than the dial — a rig that
+      // wandered a kilohertz every frame could never be told to tune.
       const frame = () => JSON.stringify({
         ...status,
-        status: { ...status.status, freq: { hz: 100_000_000 + (Date.now() % 1000) } },
+        status: { ...status.status, rx: { ...status.status.rx, sig: meterDb + ((Date.now() % 3) - 1) } },
       });
       response.write(`data: ${frame()}\n\n`);
       const timer = setInterval(() => {

src/trx-client/trx-frontend/trx-frontend-http/src/api/assets.rs

@@ -101,6 +101,12 @@ pub(crate) async fn statistics_index(req: HttpRequest) -> impl Responder {
     static_asset_response(&req, "text/html; charset=utf-8", c)
 }
 
+#[get("/satellites")]
+pub(crate) async fn satellites_index(req: HttpRequest) -> impl Responder {
+    let c = gz_index_html();
+    static_asset_response(&req, "text/html; charset=utf-8", c)
+}
+
 #[get("/bookmarks")]
 pub(crate) async fn bookmarks_index(req: HttpRequest) -> impl Responder {
     let c = gz_index_html();
@@ -175,21 +181,34 @@ pub(crate) async fn generated_asset(req: HttpRequest, path: web::Path<String>) -
     static_asset_response(&req, content_type, entry)
 }
 
+/// Serve a received SSTV picture out of the local cache.
+#[get("/sstv-images/{filename}")]
+pub(crate) async fn sstv_image(path: web::Path<String>) -> impl Responder {
+    cached_png("sstv", &path.into_inner())
+}
+
 #[get("/images/{filename}")]
 pub(crate) async fn wefax_image(path: web::Path<String>) -> impl Responder {
-    let filename = path.into_inner();
-    // Reject path traversal attempts.
+    cached_png("wefax", &path.into_inner())
+}
+
+/// Read a PNG out of one of the decoder cache directories.
+///
+/// The file name comes from a client, so it is checked rather than trusted: no
+/// separators, no parent references, and a .png suffix. Everything a decoder
+/// writes is named that way, and nothing else in the cache is servable.
+fn cached_png(decoder: &str, filename: &str) -> HttpResponse {
     if filename.contains('/') || filename.contains('\\') || filename.contains("..") {
         return HttpResponse::BadRequest().body("invalid filename");
     }
     if !filename.ends_with(".png") {
         return HttpResponse::BadRequest().body("only .png files are accessible");
     }
-    let dir = dirs::cache_dir()
+    let file_path = dirs::cache_dir()
         .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
         .join("trx-rs")
-        .join("wefax");
-    let file_path = dir.join(&filename);
+        .join(decoder)
+        .join(filename);
     match std::fs::read(&file_path) {
         Ok(data) => HttpResponse::Ok()
             .insert_header((header::CONTENT_TYPE, "image/png"))

src/trx-client/trx-frontend/trx-frontend-http/src/api/decoder.rs

@@ -60,6 +60,7 @@ struct DecodeHistoryPayload {
     ft2: Vec<trx_core::decode::Ft8Message>,
     wspr: Vec<trx_core::decode::WsprMessage>,
     wefax: Vec<trx_core::decode::WefaxMessage>,
+    sstv: Vec<trx_core::decode::SstvMessage>,
 }
 
 impl DecodeHistoryPayload {
@@ -74,6 +75,7 @@ impl DecodeHistoryPayload {
             + self.ft2.len()
             + self.wspr.len()
             + self.wefax.len()
+            + self.sstv.len()
     }
 }
 
@@ -93,6 +95,7 @@ fn collect_decode_history(
         ft2: crate::server::audio::snapshot_ft2_history(context, rig_filter),
         wspr: crate::server::audio::snapshot_wspr_history(context, rig_filter),
         wefax: crate::server::audio::snapshot_wefax_history(context, rig_filter),
+        sstv: crate::server::audio::snapshot_sstv_history(context, rig_filter),
     }
 }
 
@@ -451,10 +454,40 @@ pub async fn toggle_wefax_decode(
     .await
 }
 
+#[post("/toggle_sstv_decode")]
+pub async fn toggle_sstv_decode(
+    query: web::Query<RemoteQuery>,
+    state: web::Data<watch::Receiver<RigState>>,
+    context: web::Data<Arc<FrontendRuntimeContext>>,
+    rig_tx: web::Data<mpsc::Sender<RigRequest>>,
+) -> Result<HttpResponse, Error> {
+    let q = query.into_inner();
+    let rig_state = resolve_rig_state(q.remote.as_deref(), &context, state.get_ref());
+    send_command(
+        &rig_tx,
+        RigCommand::SetSstvDecodeEnabled(!rig_state.decoders.sstv_decode_enabled),
+        q.remote,
+    )
+    .await
+}
+
 // ============================================================================
 // Decoder clear endpoints
 // ============================================================================
 
+#[post("/clear_sstv_decode")]
+pub async fn clear_sstv_decode(
+    query: web::Query<RemoteQuery>,
+    rig_tx: web::Data<mpsc::Sender<RigRequest>>,
+) -> Result<HttpResponse, Error> {
+    send_command(
+        &rig_tx,
+        RigCommand::ResetSstvDecoder,
+        query.into_inner().remote,
+    )
+    .await
+}
+
 #[post("/clear_wefax_decode")]
 pub async fn clear_wefax_decode(
     query: web::Query<RemoteQuery>,

src/trx-client/trx-frontend/trx-frontend-http/src/api/mod.rs

@@ -591,6 +591,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(decoder::toggle_wspr_decode)
         .service(decoder::toggle_lrpt_decode)
         .service(decoder::toggle_wefax_decode)
+        .service(decoder::toggle_sstv_decode)
         .service(decoder::clear_ais_decode)
         .service(decoder::clear_vdes_decode)
         .service(decoder::clear_aprs_decode)
@@ -602,6 +603,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(decoder::clear_wspr_decode)
         .service(decoder::clear_lrpt_decode)
         .service(decoder::clear_wefax_decode)
+        .service(decoder::clear_sstv_decode)
         // Bookmark CRUD
         .service(bookmarks::list_bookmarks)
         .service(bookmarks::create_bookmark)
@@ -637,6 +639,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(assets::recorder_index)
         .service(assets::settings_index)
         .service(assets::about_index)
+        .service(assets::satellites_index)
         .service(assets::statistics_index)
         .service(assets::bookmarks_index)
         .service(assets::favicon)
@@ -645,6 +648,7 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
         .service(assets::style_css)
         .service(assets::themes_css)
         .service(assets::wefax_image)
+        .service(assets::sstv_image)
         .service(assets::bandplan_json)
         // Vendored DSEG14 Classic font
         .service(assets::dseg14_classic_woff2)

src/trx-client/trx-frontend/trx-frontend-http/src/audio.rs

@@ -24,8 +24,8 @@ use tracing::warn;
 use uuid::Uuid;
 
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, VdesMessage, WefaxMessage,
-    WsprMessage,
+    AisMessage, AprsPacket, CwEvent, DecodedMessage, Ft8Message, SstvMessage, VdesMessage,
+    WefaxMessage, WsprMessage,
 };
 use trx_frontend::FrontendRuntimeContext;
 
@@ -335,6 +335,43 @@ fn record_wefax(context: &FrontendRuntimeContext, mut msg: WefaxMessage) {
     }
 }
 
+/// Store a received picture, saving the PNG the server sent into the local
+/// cache so `/images/` can serve it back.
+fn record_sstv(context: &FrontendRuntimeContext, mut msg: SstvMessage) {
+    if let Some(ref data) = msg.png_data {
+        if let Some(ref path) = msg.path {
+            if let Some(filename) = std::path::Path::new(path).file_name() {
+                let dir = dirs::cache_dir()
+                    .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
+                    .join("trx-rs")
+                    .join("sstv");
+                if std::fs::create_dir_all(&dir).is_ok() {
+                    if let Ok(bytes) = base64::engine::general_purpose::STANDARD.decode(data) {
+                        let local_path = dir.join(filename);
+                        if let Err(e) = std::fs::write(&local_path, &bytes) {
+                            tracing::warn!("SSTV: failed to save local image: {}", e);
+                        }
+                    }
+                }
+            }
+        }
+    }
+    // The picture itself is on disk now; keeping a megabyte of base64 per
+    // entry in memory is what the history does not need.
+    msg.png_data = None;
+
+    let rig_id = msg.rig_id.clone().or_else(|| active_rig_id(context));
+    let mut history = context
+        .decode_history
+        .sstv
+        .lock()
+        .expect("sstv history mutex poisoned");
+    history.push_back((Instant::now(), rig_id, msg));
+    while history.len() > 100 {
+        history.pop_front();
+    }
+}
+
 /// Returns `true` if the entry's rig_id matches the optional filter.
 /// `None` filter means "all rigs".
 fn matches_rig_filter(entry_rig: Option<&str>, filter: Option<&str>) -> bool {
@@ -526,6 +563,31 @@ pub fn snapshot_wefax_history(
         .collect()
 }
 
+pub fn snapshot_sstv_history(
+    context: &FrontendRuntimeContext,
+    rig_filter: Option<&str>,
+) -> Vec<SstvMessage> {
+    let history = context
+        .decode_history
+        .sstv
+        .lock()
+        .expect("sstv history mutex poisoned");
+    history
+        .iter()
+        .filter(|(_, rid, _)| matches_rig_filter(rid.as_deref(), rig_filter))
+        .map(|(_, _, msg)| msg.clone())
+        .collect()
+}
+
+pub fn clear_sstv_history(context: &FrontendRuntimeContext) {
+    let mut history = context
+        .decode_history
+        .sstv
+        .lock()
+        .expect("sstv history mutex poisoned");
+    history.clear();
+}
+
 pub fn clear_wefax_history(context: &FrontendRuntimeContext) {
     let mut history = context
         .decode_history
@@ -650,6 +712,9 @@ pub fn start_decode_history_collector(context: Arc<FrontendRuntimeContext>) {
                     DecodedMessage::Wspr(msg) => record_wspr(&context, msg),
                     DecodedMessage::Wefax(msg) => record_wefax(&context, msg),
                     DecodedMessage::WefaxProgress(_) => {}
+                    DecodedMessage::Sstv(msg) => record_sstv(&context, msg),
+                    // Progress is for watching, not for keeping.
+                    DecodedMessage::SstvProgress(_) => {}
                     DecodedMessage::LrptImage(_) => {}
                     DecodedMessage::LrptProgress(_) => {}
                 },

src/trx-config/Cargo.toml

@@ -0,0 +1,24 @@
+# SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+[package]
+name = "trx-config"
+version.workspace = true
+edition = "2021"
+license = "GPL-2.0-or-later"
+
+[dependencies]
+serde = { workspace = true, features = ["derive"] }
+toml = { workspace = true }
+tracing = { workspace = true }
+dirs = "6"
+thiserror = "2"
+trx-core = { path = "../trx-core" }
+trx-decode-log = { path = "../decoders/trx-decode-log" }
+trx-reporting = { path = "../trx-reporting" }
+serde_ignored = "0.1"
+toml_edit = "0.22"
+
+[dev-dependencies]
+tempfile = "3"

src/trx-config/examples/generate_example.rs

@@ -0,0 +1,29 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Regenerate `trx-rs.toml.example` from the config structs.
+//!
+//! Run from anywhere in the workspace:
+//!
+//! ```text
+//! cargo run -p trx-config --example generate_example
+//! ```
+//!
+//! A test in `trx_config::example` fails when the checked-in file no longer
+//! matches, which is the reminder to run this.
+
+use std::path::PathBuf;
+
+fn main() -> std::io::Result<()> {
+    let target: PathBuf = std::env::args()
+        .nth(1)
+        .map(PathBuf::from)
+        .unwrap_or_else(|| {
+            PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../../trx-rs.toml.example")
+        });
+
+    std::fs::write(&target, trx_config::example::combined_example())?;
+    println!("Wrote {}", target.display());
+    Ok(())
+}

src/trx-config/src/example.rs

@@ -0,0 +1,295 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Generating the example configuration from the config structs.
+//!
+//! `trx-rs.toml.example` used to be maintained by hand and had fallen years
+//! behind the code — no `[[rigs]]`, no `[[remotes]]`, no `[timeouts]`, no
+//! bandplan settings.  It is now produced from the structs themselves, so a new
+//! field appears in the example the moment it exists, and a test fails if the
+//! checked-in copy drifts.
+//!
+//! Section comments come from the table below.  A section without an entry is
+//! still emitted — only its explanatory text is missing — so forgetting to add
+//! one can never drop a setting from the example.
+
+use toml_edit::{DocumentMut, Item};
+
+use crate::{ClientConfig, ServerConfig};
+
+const HEADER: &str = "\
+# trx-rs example configuration
+#
+# Generated from the config structs; regenerate with:
+#     cargo run -p trx-config --example generate_example
+#
+# Both sections are optional: trx-server reads [trx-server], trx-client reads
+# [trx-client], and either may live in its own file with the section header
+# omitted.  Any string may use ${ENV_VAR}, and credentials may be moved out of
+# this file with the matching *_file keys.
+#
+# Check a config without starting anything:
+#     trx-server --check-config --config trx-rs.toml
+#     trx-client --check-config --config trx-rs.toml
+";
+
+/// Explanatory comments for config sections, keyed by dotted path.
+const SECTION_COMMENTS: &[(&str, &str)] = &[
+    ("trx-server", "Server: drives the radio hardware."),
+    (
+        "trx-server.general",
+        "Station identity.  Coordinates feed PSKReporter and the map.",
+    ),
+    (
+        "trx-server.rig",
+        "Single-rig layout.  For several radios, delete this and use [[rigs]].",
+    ),
+    (
+        "trx-server.rig.access",
+        "How to reach the radio: serial, tcp, or sdr.",
+    ),
+    ("trx-server.behavior", "CAT polling and retry behaviour."),
+    (
+        "trx-server.listen",
+        "JSON control listener that trx-client connects to.",
+    ),
+    (
+        "trx-server.listen.auth",
+        "Tokens clients must present.  Empty means no authentication.\n\
+         Use tokens_file = \"/etc/trx-rs/tokens\" to keep them out of this file.",
+    ),
+    ("trx-server.audio", "Opus audio stream for trx-client."),
+    (
+        "trx-server.decoders",
+        "Which decoders run.  Trimming this list saves real CPU on small boxes.\n\
+         Valid names: aprs, aprs_hf, ais, cw, ft2, ft4, ft8, lrpt, sstv, vdes, wefax, wspr.\n\
+         output_dir sets where sstv/wefax/lrpt write images (default: user cache dir).",
+    ),
+    (
+        "trx-server.pskreporter",
+        "Report FT8/FT4/WSPR spots to pskreporter.info.",
+    ),
+    (
+        "trx-server.aprsfi",
+        "Forward received APRS frames to APRS-IS.",
+    ),
+    (
+        "trx-server.decode_logs",
+        "Write decodes to JSON Lines files.",
+    ),
+    (
+        "trx-server.sdr",
+        "SoapySDR pipeline; used when [rig.access] type = \"sdr\".",
+    ),
+    (
+        "trx-server.sdr.gain",
+        "\"auto\" for hardware AGC, or \"manual\".",
+    ),
+    (
+        "trx-server.sdr.squelch",
+        "Software squelch on demodulated audio.",
+    ),
+    (
+        "trx-server.sdr.noise_blanker",
+        "Impulse-noise suppression on the IQ stream.",
+    ),
+    (
+        "trx-server.timeouts",
+        "Timeout and buffer tuning.  The defaults suit most setups.",
+    ),
+    ("trx-client", "Client: exposes the radio to users."),
+    ("trx-client.general", "Labels shown in the web UI."),
+    (
+        "trx-client.remote",
+        "Legacy single-remote form; prefer [[remotes]] below.",
+    ),
+    (
+        "trx-client.frontends.http",
+        "Web UI.  default_rig_name and the per-rig maps are keyed by the\n\
+         [[remotes]] name, not the server-side rig id.",
+    ),
+    (
+        "trx-client.frontends.http.auth",
+        "Passphrase login for the web UI.  rx_passphrase_file and\n\
+         control_passphrase_file keep the secrets out of this file.",
+    ),
+    (
+        "trx-client.frontends.rigctl",
+        "Hamlib-compatible TCP interface, one listener per rig.",
+    ),
+    (
+        "trx-client.frontends.http_json",
+        "JSON-over-TCP control interface.",
+    ),
+    (
+        "trx-client.frontends.audio",
+        "Where to fetch the audio stream from.",
+    ),
+    (
+        "trx-client.frontends.audio.bridge",
+        "Play RX audio on a local sound device and capture TX from one.",
+    ),
+];
+
+/// Render the combined `trx-rs.toml.example` contents.
+pub fn combined_example() -> String {
+    let mut doc = DocumentMut::new();
+    doc.decor_mut().set_prefix(HEADER);
+
+    doc.insert("trx-server", section_item(&ServerConfig::example_config()));
+    doc.insert("trx-client", section_item(&ClientConfig::example_config()));
+
+    // Each section was serialized on its own, so both carry table positions
+    // starting at zero and would otherwise render interleaved.
+    renumber_tables(&mut doc);
+
+    for (path, comment) in SECTION_COMMENTS {
+        annotate(&mut doc, path, comment);
+    }
+
+    doc.to_string()
+}
+
+/// Renumber every table so the document renders in tree order.
+fn renumber_tables(doc: &mut DocumentMut) {
+    fn walk(item: &mut Item, next: &mut usize) {
+        match item {
+            Item::Table(table) => {
+                table.set_position(*next);
+                *next += 1;
+                for (_, child) in table.iter_mut() {
+                    walk(child, next);
+                }
+            }
+            Item::ArrayOfTables(array) => {
+                for table in array.iter_mut() {
+                    table.set_position(*next);
+                    *next += 1;
+                    for (_, child) in table.iter_mut() {
+                        walk(child, next);
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+    let mut next = 0;
+    for (_, item) in doc.as_table_mut().iter_mut() {
+        walk(item, &mut next);
+    }
+}
+
+/// Serialize one config into a toml_edit table.
+fn section_item<T: serde::Serialize>(config: &T) -> Item {
+    let rendered = toml::to_string_pretty(config).unwrap_or_default();
+    let doc: DocumentMut = rendered.parse().expect("serialized config must re-parse");
+    Item::Table(doc.as_table().clone())
+}
+
+/// Attach a comment above the table at `path`, if it exists.
+fn annotate(doc: &mut DocumentMut, path: &str, comment: &str) {
+    let mut item: Option<&mut Item> = None;
+    for segment in path.split('.') {
+        let next = match item {
+            None => doc.get_mut(segment),
+            Some(current) => current.as_table_mut().and_then(|t| t.get_mut(segment)),
+        };
+        match next {
+            Some(found) => item = Some(found),
+            None => return,
+        }
+    }
+
+    let Some(table) = item.and_then(|i| i.as_table_mut()) else {
+        return;
+    };
+    let body: String = comment
+        .lines()
+        .map(|line| format!("# {}\n", line.trim_start()))
+        .collect();
+    table.decor_mut().set_prefix(format!("\n{body}"));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// The checked-in example must match what the structs produce, so a new
+    /// config field cannot land without showing up in the example.
+    #[test]
+    fn test_checked_in_example_is_up_to_date() {
+        let path = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("../../trx-rs.toml.example")
+            .canonicalize()
+            .expect("example file must exist");
+        let on_disk = std::fs::read_to_string(&path).expect("example file must be readable");
+        assert_eq!(
+            on_disk,
+            combined_example(),
+            "trx-rs.toml.example is out of date; regenerate with \
+             `cargo run -p trx-config --example generate_example`"
+        );
+    }
+
+    /// Nothing in the example may be derived from the machine that generated
+    /// it: [decode_logs].dir defaults to the running user's cache directory,
+    /// which made the generated file differ between a developer's laptop and
+    /// CI, and the up-to-date test fail for everyone but its author.
+    #[test]
+    fn test_example_has_no_machine_specific_paths() {
+        let example = combined_example();
+        for dir in [dirs::home_dir(), dirs::cache_dir(), dirs::config_dir()]
+            .into_iter()
+            .flatten()
+        {
+            let dir = dir.to_string_lossy().into_owned();
+            assert!(
+                !example.contains(&dir),
+                "the example contains this machine's {dir}; pin the value in example_config()"
+            );
+        }
+    }
+
+    #[test]
+    fn test_example_loads_and_validates() {
+        let mut file = tempfile::NamedTempFile::new().unwrap();
+        std::io::Write::write_all(&mut file, combined_example().as_bytes()).unwrap();
+
+        let server = ServerConfig::load_from_file(file.path()).expect("server section loads");
+        assert!(
+            server.unknown_keys.is_empty(),
+            "the generated example must not contain unknown keys: {:?}",
+            server.unknown_keys
+        );
+        server.config.validate().expect("server section validates");
+
+        let client = ClientConfig::load_from_file(file.path()).expect("client section loads");
+        assert!(
+            client.unknown_keys.is_empty(),
+            "the generated example must not contain unknown keys: {:?}",
+            client.unknown_keys
+        );
+        client.config.validate().expect("client section validates");
+    }
+
+    /// Every section that gained a comment must still exist under that path.
+    #[test]
+    fn test_section_comments_match_real_sections() {
+        let doc: DocumentMut = combined_example().parse().unwrap();
+        for (path, _) in SECTION_COMMENTS {
+            let mut item = None;
+            for segment in path.split('.') {
+                item = match item {
+                    None => doc.get(segment),
+                    Some(current) => current.as_table().and_then(|t| t.get(segment)),
+                };
+                assert!(
+                    item.is_some(),
+                    "commented section [{path}] no longer exists"
+                );
+            }
+        }
+    }
+}

src/trx-config/src/file.rs

@@ -0,0 +1,252 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Loading a config section out of a TOML file.
+//!
+//! Two file shapes are accepted:
+//!
+//! - **Sectioned** — a combined `trx-rs.toml` with `[trx-server]` and/or
+//!   `[trx-client]` tables.  This is what `--print-config` and
+//!   `trx-configurator` emit.
+//! - **Bare** — a standalone file whose root *is* the section, i.e. `[general]`
+//!   and `[rig]` at the top level.  Hand-written per-binary configs use this.
+//!
+//! A file that carries some other component's section but not ours is treated
+//! as "section absent" rather than as a bare file, so loading a client-only
+//! config with the server reports the missing section instead of silently
+//! falling back to defaults.
+
+use serde::de::DeserializeOwned;
+use serde::Serialize;
+use std::path::{Path, PathBuf};
+use thiserror::Error;
+
+use std::collections::BTreeSet;
+
+use crate::unknown::{describe, flatten_paths, UnknownKey};
+
+/// Every section key that may appear at the root of a combined config file.
+pub const SECTION_KEYS: &[&str] = &["trx-server", "trx-client"];
+
+/// A loaded config plus what the loader noticed on the way in.
+#[derive(Debug, Clone)]
+pub struct ConfigLoad<T> {
+    /// The deserialized configuration.
+    pub config: T,
+    /// File the config came from; `None` when nothing was found and defaults
+    /// were used.
+    pub path: Option<PathBuf>,
+    /// Keys present in the file that no config field claimed.
+    pub unknown_keys: Vec<UnknownKey>,
+    /// Every key path the file actually set.  Defaults are indistinguishable
+    /// from explicit values once deserialized, so deprecation checks need this.
+    pub present_keys: BTreeSet<String>,
+}
+
+impl<T: ConfigFile> ConfigLoad<T> {
+    /// Log a warning for every deprecated key the file sets.
+    pub fn report_deprecations(&self) {
+        for message in T::deprecations(&self.present_keys) {
+            tracing::warn!("{}", message);
+        }
+    }
+}
+
+impl<T> ConfigLoad<T> {
+    /// Log every unknown key as a warning.  With `strict`, also return an error
+    /// so the caller can refuse to start.
+    pub fn report_unknown_keys(&self, strict: bool) -> Result<(), String> {
+        for key in &self.unknown_keys {
+            tracing::warn!("{}", key);
+        }
+        if strict && !self.unknown_keys.is_empty() {
+            return Err(format!(
+                "{} unknown config key(s); refusing to start because --strict-config is set",
+                self.unknown_keys.len()
+            ));
+        }
+        Ok(())
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum ConfigError {
+    #[error("Failed to read config file {0}: {1}")]
+    ReadError(PathBuf, String),
+
+    #[error("Failed to parse config file {0}: {1}")]
+    ParseError(PathBuf, String),
+}
+
+/// Returns the default search paths for `trx-rs.toml`
+/// (current directory → XDG config → /etc).
+fn config_search_paths() -> Vec<PathBuf> {
+    let mut paths = vec![PathBuf::from("trx-rs.toml")];
+    if let Some(config_dir) = dirs::config_dir() {
+        paths.push(config_dir.join("trx-rs").join("trx-rs.toml"));
+    }
+    paths.push(PathBuf::from("/etc/trx-rs/trx-rs.toml"));
+    paths
+}
+
+/// Pick the table holding `key`'s settings out of a parsed document.
+///
+/// Returns the named section when present, the whole document when it carries
+/// no section headers at all (a bare standalone file), or `None` when the file
+/// is sectioned but has no section for `key`.
+fn select_section(table: &toml::Table, key: &str) -> Option<toml::Value> {
+    if let Some(section) = table.get(key) {
+        return Some(section.clone());
+    }
+    let is_sectioned = SECTION_KEYS.iter().any(|k| table.contains_key(*k));
+    if is_sectioned {
+        return None;
+    }
+    Some(toml::Value::Table(table.clone()))
+}
+
+/// Extract and deserialize a named section from a TOML file.
+///
+/// Returns `Ok(Some((cfg, unknown_keys)))` when the section is present and
+/// parses cleanly, `Ok(None)` when the section is absent, or `Err` on I/O /
+/// parse failure.
+type LoadedSection<T> = (T, Vec<UnknownKey>, BTreeSet<String>);
+
+fn load_section_from_file<T: ConfigFile>(
+    path: &Path,
+    key: &str,
+) -> Result<Option<LoadedSection<T>>, ConfigError> {
+    let content = std::fs::read_to_string(path)
+        .map_err(|e| ConfigError::ReadError(path.to_path_buf(), e.to_string()))?;
+
+    let table: toml::Table = toml::from_str(&content)
+        .map_err(|e| ConfigError::ParseError(path.to_path_buf(), e.to_string()))?;
+
+    let Some(mut section) = select_section(&table, key) else {
+        return Ok(None);
+    };
+
+    // ${VAR} references are expanded before deserializing, so any string in the
+    // file can come from the environment.
+    crate::secrets::expand_env_vars(&mut section)
+        .map_err(|e| ConfigError::ParseError(path.to_path_buf(), e))?;
+
+    let present_keys = flatten_paths(&section);
+
+    // Deserialize straight from the TOML value so serde applies every default,
+    // recording any key no field claimed.
+    let mut ignored: Vec<String> = Vec::new();
+    let cfg: T = serde_ignored::deserialize(section, |path| ignored.push(path.to_string()))
+        .map_err(|e| ConfigError::ParseError(path.to_path_buf(), e.to_string()))?;
+
+    Ok(Some((
+        cfg,
+        describe(&ignored, &T::reference_value()),
+        present_keys,
+    )))
+}
+
+/// Trait for loading configuration from a `trx-rs.toml` section.
+pub trait ConfigFile: Sized + Default + DeserializeOwned + Serialize {
+    /// Section key in `trx-rs.toml` (e.g. `"trx-server"` or `"trx-client"`).
+    fn section_key() -> &'static str;
+
+    /// Warnings for deprecated keys the file sets, given every key path present
+    /// in it.  Defaults to none.
+    fn deprecations(_present_keys: &BTreeSet<String>) -> Vec<String> {
+        Vec::new()
+    }
+
+    /// A TOML rendering of a populated config, used to suggest corrections for
+    /// unknown keys.  Implementations should fill in list-valued sections such
+    /// as `[[rigs]]` so keys nested inside them can be suggested too.
+    fn reference_value() -> toml::Value {
+        toml::Value::try_from(Self::default())
+            .unwrap_or_else(|_| toml::Value::Table(toml::Table::new()))
+    }
+
+    /// Load the section from a specific file path.
+    ///
+    /// Accepts both a sectioned file (`[<section_key>]` at the root) and a bare
+    /// file whose root is the section itself.  Returns an error if the file
+    /// cannot be read, is not valid TOML, or is sectioned for some other
+    /// component only.
+    fn load_from_file(path: &Path) -> Result<ConfigLoad<Self>, ConfigError> {
+        let (config, unknown_keys, present_keys) =
+            load_section_from_file::<Self>(path, Self::section_key())?.ok_or_else(|| {
+                ConfigError::ParseError(
+                    path.to_path_buf(),
+                    format!("missing [{}] section", Self::section_key()),
+                )
+            })?;
+        Ok(ConfigLoad {
+            config,
+            path: Some(path.to_path_buf()),
+            unknown_keys,
+            present_keys,
+        })
+    }
+
+    /// Search default paths (`trx-rs.toml` in CWD → XDG → /etc) and load
+    /// the first file that contains the expected section.
+    ///
+    /// Falls back to `Self::default()` with no path when nothing is found.
+    fn load_from_default_paths() -> Result<ConfigLoad<Self>, ConfigError> {
+        for path in config_search_paths() {
+            if path.exists() {
+                if let Some((config, unknown_keys, present_keys)) =
+                    load_section_from_file::<Self>(&path, Self::section_key())?
+                {
+                    return Ok(ConfigLoad {
+                        config,
+                        path: Some(path),
+                        unknown_keys,
+                        present_keys,
+                    });
+                }
+            }
+        }
+        Ok(ConfigLoad {
+            config: Self::default(),
+            path: None,
+            unknown_keys: Vec::new(),
+            present_keys: BTreeSet::new(),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn table(s: &str) -> toml::Table {
+        toml::from_str(s).unwrap()
+    }
+
+    #[test]
+    fn test_select_section_prefers_named_section() {
+        let t = table("[trx-server]\n[trx-server.general]\ncallsign = \"W1AW\"\n");
+        let section = select_section(&t, "trx-server").unwrap();
+        assert!(section.get("general").is_some());
+    }
+
+    #[test]
+    fn test_select_section_falls_back_to_root_for_bare_file() {
+        let t = table("[general]\ncallsign = \"W1AW\"\n");
+        let section = select_section(&t, "trx-server").unwrap();
+        assert!(section.get("general").is_some());
+    }
+
+    #[test]
+    fn test_select_section_absent_when_other_section_present() {
+        let t = table("[trx-client]\n[trx-client.general]\ncallsign = \"W1AW\"\n");
+        assert!(select_section(&t, "trx-server").is_none());
+    }
+
+    #[test]
+    fn test_select_section_empty_file_is_bare() {
+        let t = table("");
+        assert!(select_section(&t, "trx-server").is_some());
+    }
+}

src/trx-config/src/lib.rs

@@ -0,0 +1,26 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Configuration types shared by `trx-server`, `trx-client` and
+//! `trx-configurator`.
+//!
+//! Keeping the structs, the loader and the validators in one crate means the
+//! setup wizard checks a config with exactly the same code the binaries load
+//! it with, so the two can never drift apart.
+
+pub mod client;
+pub mod example;
+pub mod file;
+pub mod secrets;
+pub mod server;
+pub mod shared;
+pub mod unknown;
+pub mod url;
+
+pub use client::ClientConfig;
+pub use file::{ConfigError, ConfigFile, ConfigLoad};
+pub use server::ServerConfig;
+pub use shared::{validate_log_level, validate_tokens};
+pub use unknown::UnknownKey;
+pub use url::{parse_audio_url, parse_remote_url, RemoteEndpoint};

src/trx-config/src/secrets.rs

@@ -0,0 +1,297 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Keeping credentials out of the config file.
+//!
+//! Tokens and passphrases used to have exactly one representation: written in
+//! plain text in `trx-rs.toml`, which is awkward when the config is deployed by
+//! a config-management tool, committed to a private repo, or shared between
+//! machines.  Two alternatives are offered:
+//!
+//! - `${VAR}` anywhere in a config string, expanded from the environment.
+//! - A `*_file` sibling of any secret key, read from disk at startup.
+//!
+//! Plus a nudge: a config that holds secrets and is readable by group or others
+//! gets a warning.
+
+use std::path::Path;
+
+/// Expand `${VAR}` references in every string in a TOML value.
+///
+/// An unset variable is an error rather than an empty string — a silently blank
+/// passphrase is the kind of thing that disables authentication by accident.
+pub fn expand_env_vars(value: &mut toml::Value) -> Result<(), String> {
+    match value {
+        toml::Value::String(s) => {
+            if let Some(expanded) = expand_str(s)? {
+                *s = expanded;
+            }
+        }
+        toml::Value::Table(table) => {
+            for (_, child) in table.iter_mut() {
+                expand_env_vars(child)?;
+            }
+        }
+        toml::Value::Array(items) => {
+            for item in items.iter_mut() {
+                expand_env_vars(item)?;
+            }
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+/// Expand `${VAR}` in one string; `None` when there was nothing to expand.
+fn expand_str(input: &str) -> Result<Option<String>, String> {
+    if !input.contains("${") {
+        return Ok(None);
+    }
+
+    let mut out = String::with_capacity(input.len());
+    let mut rest = input;
+    while let Some(start) = rest.find("${") {
+        out.push_str(&rest[..start]);
+        let after = &rest[start + 2..];
+        let Some(end) = after.find('}') else {
+            // Unterminated: leave the rest exactly as written.
+            out.push_str(&rest[start..]);
+            return Ok(Some(out));
+        };
+        let name = &after[..end];
+        if name.is_empty() || !name.bytes().all(|b| b.is_ascii_alphanumeric() || b == b'_') {
+            // Not a variable reference; pass it through untouched.
+            out.push_str(&rest[start..start + 2 + end + 1]);
+        } else {
+            let value = std::env::var(name)
+                .map_err(|_| format!("config references unset environment variable ${{{name}}}"))?;
+            out.push_str(&value);
+        }
+        rest = &after[end + 1..];
+    }
+    out.push_str(rest);
+    Ok(Some(out))
+}
+
+/// Read a single secret from a file: the whole file, trimmed.
+pub fn read_secret_file(path: &str, what: &str) -> Result<String, String> {
+    let content = std::fs::read_to_string(path)
+        .map_err(|e| format!("{what}: cannot read secret file {path}: {e}"))?;
+    let secret = content.trim().to_string();
+    if secret.is_empty() {
+        return Err(format!("{what}: secret file {path} is empty"));
+    }
+    warn_if_group_readable(Path::new(path), what);
+    Ok(secret)
+}
+
+/// Read a list of secrets, one per line.  Blank lines and `#` comments are
+/// skipped.
+pub fn read_secret_list_file(path: &str, what: &str) -> Result<Vec<String>, String> {
+    let content = std::fs::read_to_string(path)
+        .map_err(|e| format!("{what}: cannot read secret file {path}: {e}"))?;
+    let secrets: Vec<String> = content
+        .lines()
+        .map(str::trim)
+        .filter(|line| !line.is_empty() && !line.starts_with('#'))
+        .map(str::to_string)
+        .collect();
+    if secrets.is_empty() {
+        return Err(format!("{what}: secret file {path} contains no entries"));
+    }
+    warn_if_group_readable(Path::new(path), what);
+    Ok(secrets)
+}
+
+/// Fill `inline` from `file` when the config used the `*_file` form.
+///
+/// Setting both is an error: which one wins would be a guess.
+pub fn resolve_secret(
+    inline: &mut Option<String>,
+    file: &Option<String>,
+    what: &str,
+) -> Result<(), String> {
+    let Some(path) = file else {
+        return Ok(());
+    };
+    if inline.is_some() {
+        return Err(format!(
+            "{what}: set either the value or its _file form, not both"
+        ));
+    }
+    *inline = Some(read_secret_file(path, what)?);
+    Ok(())
+}
+
+/// Fill a token list from `file` when the config used the `*_file` form.
+pub fn resolve_secret_list(
+    inline: &mut Vec<String>,
+    file: &Option<String>,
+    what: &str,
+) -> Result<(), String> {
+    let Some(path) = file else {
+        return Ok(());
+    };
+    if !inline.is_empty() {
+        return Err(format!(
+            "{what}: set either the value or its _file form, not both"
+        ));
+    }
+    *inline = read_secret_list_file(path, what)?;
+    Ok(())
+}
+
+/// Warn when a file holding secrets is readable beyond its owner.
+///
+/// Advisory only: plenty of valid setups (a dedicated service user, an
+/// immutable image) are fine, so this never fails the load.
+pub fn warn_if_group_readable(path: &Path, what: &str) {
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let Ok(meta) = std::fs::metadata(path) else {
+            return;
+        };
+        let mode = meta.permissions().mode() & 0o077;
+        if mode != 0 {
+            tracing::warn!(
+                "{} is readable by group or others (mode {:o}); it holds secrets ({}). \
+                 Consider: chmod 600 {}",
+                path.display(),
+                meta.permissions().mode() & 0o777,
+                what,
+                path.display()
+            );
+        }
+    }
+    #[cfg(not(unix))]
+    {
+        let _ = (path, what);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::io::Write;
+
+    #[test]
+    fn test_expand_leaves_plain_strings_alone() {
+        assert_eq!(expand_str("plain").unwrap(), None);
+        assert_eq!(expand_str("TRXRS-%YYYY%.log").unwrap(), None);
+    }
+
+    #[test]
+    fn test_expand_substitutes_variable() {
+        std::env::set_var("TRX_TEST_TOKEN", "s3cret");
+        assert_eq!(
+            expand_str("Bearer ${TRX_TEST_TOKEN}!").unwrap().as_deref(),
+            Some("Bearer s3cret!")
+        );
+    }
+
+    #[test]
+    fn test_expand_errors_on_unset_variable() {
+        let err = expand_str("${TRX_DEFINITELY_NOT_SET_12345}").unwrap_err();
+        assert!(err.contains("unset environment variable"), "{err}");
+    }
+
+    #[test]
+    fn test_expand_passes_through_non_variables() {
+        assert_eq!(
+            expand_str("${not a var}").unwrap().as_deref(),
+            Some("${not a var}")
+        );
+        assert_eq!(
+            expand_str("unterminated ${VAR").unwrap().as_deref(),
+            Some("unterminated ${VAR")
+        );
+    }
+
+    #[test]
+    fn test_expand_walks_nested_tables_and_arrays() {
+        std::env::set_var("TRX_TEST_HOST", "radio.example.com");
+        let mut value: toml::Value = toml::from_str(
+            r#"
+[remote]
+url = "${TRX_TEST_HOST}:4530"
+hosts = ["${TRX_TEST_HOST}"]
+"#,
+        )
+        .unwrap();
+        expand_env_vars(&mut value).unwrap();
+        assert_eq!(
+            value["remote"]["url"].as_str(),
+            Some("radio.example.com:4530")
+        );
+        assert_eq!(
+            value["remote"]["hosts"][0].as_str(),
+            Some("radio.example.com")
+        );
+    }
+
+    fn temp_file(content: &str) -> tempfile::NamedTempFile {
+        let mut f = tempfile::NamedTempFile::new().unwrap();
+        f.write_all(content.as_bytes()).unwrap();
+        f.flush().unwrap();
+        f
+    }
+
+    #[test]
+    fn test_read_secret_file_trims() {
+        let f = temp_file("  hunter2\n");
+        assert_eq!(read_secret_file(path_of(&f), "test").unwrap(), "hunter2");
+    }
+
+    #[test]
+    fn test_read_secret_file_rejects_empty() {
+        let f = temp_file("   \n");
+        assert!(read_secret_file(path_of(&f), "test").is_err());
+    }
+
+    #[test]
+    fn test_read_secret_list_skips_blanks_and_comments() {
+        let f = temp_file("# tokens\nalpha\n\n  beta  \n");
+        assert_eq!(
+            read_secret_list_file(path_of(&f), "test").unwrap(),
+            vec!["alpha".to_string(), "beta".to_string()]
+        );
+    }
+
+    #[test]
+    fn test_resolve_secret_fills_from_file() {
+        let f = temp_file("from-file");
+        let mut inline = None;
+        resolve_secret(&mut inline, &Some(path_of(&f).to_string()), "test").unwrap();
+        assert_eq!(inline.as_deref(), Some("from-file"));
+    }
+
+    #[test]
+    fn test_resolve_secret_rejects_both_forms() {
+        let f = temp_file("from-file");
+        let mut inline = Some("inline".to_string());
+        let err = resolve_secret(&mut inline, &Some(path_of(&f).to_string()), "test").unwrap_err();
+        assert!(err.contains("not both"), "{err}");
+    }
+
+    #[test]
+    fn test_resolve_secret_is_a_no_op_without_file() {
+        let mut inline = Some("inline".to_string());
+        resolve_secret(&mut inline, &None, "test").unwrap();
+        assert_eq!(inline.as_deref(), Some("inline"));
+    }
+
+    #[test]
+    fn test_resolve_secret_list_rejects_both_forms() {
+        let f = temp_file("alpha");
+        let mut inline = vec!["inline".to_string()];
+        let err =
+            resolve_secret_list(&mut inline, &Some(path_of(&f).to_string()), "test").unwrap_err();
+        assert!(err.contains("not both"), "{err}");
+    }
+
+    fn path_of(f: &tempfile::NamedTempFile) -> &str {
+        f.path().to_str().unwrap()
+    }
+}

src/trx-config/src/shared.rs

@@ -19,6 +19,52 @@
 //! would either bloat both binaries with unused fields or require a trait
 //! abstraction that adds complexity without clear benefit.
 
+use std::net::IpAddr;
+
+/// A socket a component intends to bind, and what it is for.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct BoundSocket {
+    pub addr: IpAddr,
+    pub port: u16,
+    /// Human-readable owner, e.g. `[listen]` or `[frontends.http]`.
+    pub label: String,
+}
+
+impl BoundSocket {
+    pub fn new(addr: IpAddr, port: u16, label: impl Into<String>) -> Self {
+        Self {
+            addr,
+            port,
+            label: label.into(),
+        }
+    }
+}
+
+/// Reject two components trying to bind the same socket.
+///
+/// A wildcard address (`0.0.0.0` / `::`) conflicts with any other address on
+/// the same port, since binding it claims every interface.  Port 0 means "pick
+/// an ephemeral port" and never conflicts.
+pub fn check_socket_conflicts(sockets: &[BoundSocket]) -> Result<(), String> {
+    for (i, a) in sockets.iter().enumerate() {
+        if a.port == 0 {
+            continue;
+        }
+        for b in &sockets[i + 1..] {
+            if b.port != a.port {
+                continue;
+            }
+            if a.addr == b.addr || a.addr.is_unspecified() || b.addr.is_unspecified() {
+                return Err(format!(
+                    "{} and {} would both bind {}:{}",
+                    a.label, b.label, a.addr, a.port
+                ));
+            }
+        }
+    }
+    Ok(())
+}
+
 /// Validate that a log level string is one of the accepted values.
 ///
 /// Returns `Ok(())` when `level` is `None` (defaulting is handled elsewhere)
@@ -53,6 +99,47 @@ pub fn validate_tokens(path: &str, tokens: &[String]) -> Result<(), String> {
 mod tests {
     use super::*;
 
+    fn sock(addr: &str, port: u16, label: &str) -> BoundSocket {
+        BoundSocket::new(addr.parse().unwrap(), port, label)
+    }
+
+    #[test]
+    fn test_socket_conflicts_detects_exact_duplicate() {
+        let err = check_socket_conflicts(&[
+            sock("127.0.0.1", 8080, "[frontends.http]"),
+            sock("127.0.0.1", 8080, "[frontends.http_json]"),
+        ])
+        .unwrap_err();
+        assert!(err.contains("127.0.0.1:8080"), "unexpected error: {err}");
+    }
+
+    #[test]
+    fn test_socket_conflicts_detects_wildcard_overlap() {
+        assert!(check_socket_conflicts(&[
+            sock("0.0.0.0", 4530, "[listen]"),
+            sock("127.0.0.1", 4530, "[audio]"),
+        ])
+        .is_err());
+    }
+
+    #[test]
+    fn test_socket_conflicts_allows_distinct_addresses() {
+        assert!(check_socket_conflicts(&[
+            sock("127.0.0.1", 4530, "[listen]"),
+            sock("192.168.1.5", 4530, "[audio]"),
+        ])
+        .is_ok());
+    }
+
+    #[test]
+    fn test_socket_conflicts_ignores_ephemeral_ports() {
+        assert!(check_socket_conflicts(&[
+            sock("127.0.0.1", 0, "[frontends.http_json]"),
+            sock("127.0.0.1", 0, "[frontends.http]"),
+        ])
+        .is_ok());
+    }
+
     #[test]
     fn test_validate_log_level_none() {
         assert!(validate_log_level(None).is_ok());

src/trx-config/src/unknown.rs

@@ -0,0 +1,263 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Reporting for config keys the deserializer ignored.
+//!
+//! Every config struct is `#[serde(default)]`, so a misspelled key used to be
+//! dropped without a word and the setting silently kept its default.  The
+//! loader now collects the ignored key paths and pairs each with the closest
+//! known key at the same level, so `prot = 9999` reads as a typo instead of
+//! looking like it worked.
+
+use std::collections::BTreeSet;
+use std::fmt;
+
+/// A config key that the deserializer did not recognise.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct UnknownKey {
+    /// Dotted path of the key, e.g. `listen.prot` or `rigs.0.audio.prot`.
+    pub path: String,
+    /// Closest known key at the same level, when one is near enough to suggest.
+    pub suggestion: Option<String>,
+}
+
+impl fmt::Display for UnknownKey {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match &self.suggestion {
+            Some(s) => write!(
+                f,
+                "unknown config key '{}' (did you mean '{}'?)",
+                self.path, s
+            ),
+            None => write!(f, "unknown config key '{}'", self.path),
+        }
+    }
+}
+
+/// Flatten a TOML value into the set of dotted key paths it contains.
+///
+/// Array indices are normalised to `0` so a path inside `[[rigs]]` matches
+/// whichever entry it came from.
+pub fn flatten_paths(value: &toml::Value) -> BTreeSet<String> {
+    let mut paths = BTreeSet::new();
+    walk(value, "", &mut paths);
+    paths
+}
+
+fn walk(value: &toml::Value, prefix: &str, paths: &mut BTreeSet<String>) {
+    let join = |seg: &str| {
+        if prefix.is_empty() {
+            seg.to_string()
+        } else {
+            format!("{prefix}.{seg}")
+        }
+    };
+    match value {
+        toml::Value::Table(table) => {
+            for (key, child) in table {
+                let path = join(key);
+                paths.insert(path.clone());
+                walk(child, &path, paths);
+            }
+        }
+        toml::Value::Array(items) => {
+            // Every entry of an array of tables has the same shape, so collapse
+            // them onto index 0 and let one entry stand for all.
+            for item in items {
+                let path = join("0");
+                walk(item, &path, paths);
+            }
+        }
+        _ => {}
+    }
+}
+
+/// Replace numeric path segments with `0` so array entries compare equal.
+fn normalize(path: &str) -> String {
+    path.split('.')
+        .map(|seg| {
+            if !seg.is_empty() && seg.bytes().all(|b| b.is_ascii_digit()) {
+                "0"
+            } else {
+                seg
+            }
+        })
+        .collect::<Vec<_>>()
+        .join(".")
+}
+
+/// Suggest the closest known key that sits at the same level as `path`.
+///
+/// Returns `None` when nothing is close enough to be worth printing.
+pub fn suggest(path: &str, known: &BTreeSet<String>) -> Option<String> {
+    let normalized = normalize(path);
+    let (parent, leaf) = match normalized.rsplit_once('.') {
+        Some((parent, leaf)) => (parent, leaf),
+        None => ("", normalized.as_str()),
+    };
+
+    // Anything longer than this is a different word, not a typo.
+    let limit = (leaf.chars().count() / 3).clamp(1, 3);
+    let mut best: Option<(usize, &str)> = None;
+
+    for candidate in known {
+        let (cand_parent, cand_leaf) = match candidate.rsplit_once('.') {
+            Some((p, l)) => (p, l),
+            None => ("", candidate.as_str()),
+        };
+        if cand_parent != parent || cand_leaf == leaf {
+            continue;
+        }
+        let distance = edit_distance(leaf, cand_leaf);
+        if distance <= limit && best.is_none_or(|(best_d, _)| distance < best_d) {
+            best = Some((distance, cand_leaf));
+        }
+    }
+
+    best.map(|(_, leaf)| {
+        if parent.is_empty() {
+            leaf.to_string()
+        } else {
+            format!("{parent}.{leaf}")
+        }
+    })
+}
+
+/// Pair each ignored path with a suggestion drawn from `reference`.
+pub fn describe(paths: &[String], reference: &toml::Value) -> Vec<UnknownKey> {
+    let known = flatten_paths(reference);
+    paths
+        .iter()
+        .map(|path| UnknownKey {
+            path: path.clone(),
+            suggestion: suggest(path, &known),
+        })
+        .collect()
+}
+
+/// Optimal string alignment distance: Levenshtein plus transpositions, so the
+/// common `port` → `prot` slip counts as one mistake rather than two.
+fn edit_distance(a: &str, b: &str) -> usize {
+    let a: Vec<char> = a.chars().collect();
+    let b: Vec<char> = b.chars().collect();
+    if a.is_empty() {
+        return b.len();
+    }
+    if b.is_empty() {
+        return a.len();
+    }
+
+    let mut rows = vec![vec![0usize; b.len() + 1]; a.len() + 1];
+    for (i, row) in rows.iter_mut().enumerate() {
+        row[0] = i;
+    }
+    for (j, cell) in rows[0].iter_mut().enumerate() {
+        *cell = j;
+    }
+
+    for i in 1..=a.len() {
+        for j in 1..=b.len() {
+            let cost = usize::from(a[i - 1] != b[j - 1]);
+            let mut best = (rows[i - 1][j] + 1)
+                .min(rows[i][j - 1] + 1)
+                .min(rows[i - 1][j - 1] + cost);
+            if i > 1 && j > 1 && a[i - 1] == b[j - 2] && a[i - 2] == b[j - 1] {
+                best = best.min(rows[i - 2][j - 2] + 1);
+            }
+            rows[i][j] = best;
+        }
+    }
+    rows[a.len()][b.len()]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn reference() -> toml::Value {
+        toml::from_str(
+            r#"
+[general]
+callsign = "N0CALL"
+log_level = "info"
+
+[listen]
+enabled = true
+port = 4530
+
+[[rigs]]
+id = "hf"
+[rigs.audio]
+port = 4531
+sample_rate = 48000
+"#,
+        )
+        .unwrap()
+    }
+
+    #[test]
+    fn test_flatten_collects_nested_paths() {
+        let paths = flatten_paths(&reference());
+        assert!(paths.contains("general.callsign"));
+        assert!(paths.contains("listen.port"));
+        assert!(paths.contains("rigs.0.audio.sample_rate"));
+    }
+
+    #[test]
+    fn test_suggest_finds_close_sibling() {
+        let known = flatten_paths(&reference());
+        assert_eq!(
+            suggest("listen.prot", &known).as_deref(),
+            Some("listen.port")
+        );
+    }
+
+    #[test]
+    fn test_suggest_inside_array_entry() {
+        let known = flatten_paths(&reference());
+        assert_eq!(
+            suggest("rigs.1.audio.prot", &known).as_deref(),
+            Some("rigs.0.audio.port")
+        );
+    }
+
+    #[test]
+    fn test_suggest_ignores_distant_names() {
+        let known = flatten_paths(&reference());
+        assert_eq!(suggest("listen.bananas", &known), None);
+    }
+
+    #[test]
+    fn test_suggest_does_not_cross_levels() {
+        let known = flatten_paths(&reference());
+        // `port` exists under [listen], but not under [general].
+        assert_eq!(suggest("general.port", &known), None);
+    }
+
+    #[test]
+    fn test_describe_formats_message() {
+        let described = describe(&["listen.prot".to_string()], &reference());
+        assert_eq!(
+            described[0].to_string(),
+            "unknown config key 'listen.prot' (did you mean 'listen.port'?)"
+        );
+    }
+
+    #[test]
+    fn test_describe_without_suggestion() {
+        let described = describe(&["listen.bananas".to_string()], &reference());
+        assert_eq!(
+            described[0].to_string(),
+            "unknown config key 'listen.bananas'"
+        );
+    }
+
+    #[test]
+    fn test_edit_distance_counts_transposition_once() {
+        assert_eq!(edit_distance("port", "prot"), 1);
+        assert_eq!(edit_distance("port", "port"), 0);
+        assert_eq!(edit_distance("", "port"), 4);
+        assert_eq!(edit_distance("sample_rat", "sample_rate"), 1);
+    }
+}

src/trx-config/src/url.rs

@@ -0,0 +1,173 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Parsing for the `host:port` endpoint URLs used by the client's `[[remotes]]`
+//! and `[frontends.audio]` settings.
+//!
+//! These live next to the config structs because validation needs them; the
+//! client re-exports them for its connection code.
+
+/// Default port for the server's JSON control listener.
+pub const DEFAULT_REMOTE_PORT: u16 = 4530;
+/// Default port for the server's Opus audio listener.
+pub const DEFAULT_AUDIO_PORT: u16 = 4531;
+
+/// A resolved `host:port` pair.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct RemoteEndpoint {
+    pub host: String,
+    pub port: u16,
+}
+
+impl RemoteEndpoint {
+    /// Format as a connect string, bracketing bare IPv6 hosts.
+    pub fn connect_addr(&self) -> String {
+        if self.host.contains(':') && !self.host.starts_with('[') {
+            format!("[{}]:{}", self.host, self.port)
+        } else {
+            format!("{}:{}", self.host, self.port)
+        }
+    }
+}
+
+/// Parse a remote control URL, defaulting to port 4530.
+pub fn parse_remote_url(url: &str) -> Result<RemoteEndpoint, String> {
+    parse_endpoint_url(url, DEFAULT_REMOTE_PORT, "remote")
+}
+
+/// Parse an audio stream URL, defaulting to port 4531.
+pub fn parse_audio_url(url: &str) -> Result<RemoteEndpoint, String> {
+    parse_endpoint_url(url, DEFAULT_AUDIO_PORT, "audio")
+}
+
+fn parse_endpoint_url(url: &str, default_port: u16, kind: &str) -> Result<RemoteEndpoint, String> {
+    let trimmed = url.trim();
+    if trimmed.is_empty() {
+        return Err(format!("{kind} url is empty"));
+    }
+
+    let addr = trimmed
+        .strip_prefix("tcp://")
+        .or_else(|| trimmed.strip_prefix("http-json://"))
+        .or_else(|| trimmed.strip_prefix("audio://"))
+        .unwrap_or(trimmed);
+
+    parse_host_port(addr, default_port, kind)
+}
+
+fn parse_host_port(input: &str, default_port: u16, kind: &str) -> Result<RemoteEndpoint, String> {
+    if let Some(rest) = input.strip_prefix('[') {
+        let closing = rest
+            .find(']')
+            .ok_or_else(|| format!("invalid {kind} url: missing closing ']' for IPv6 host"))?;
+        let host = &rest[..closing];
+        let remainder = &rest[closing + 1..];
+        if host.is_empty() {
+            return Err(format!("invalid {kind} url: host is empty"));
+        }
+        let port = if remainder.is_empty() {
+            default_port
+        } else if let Some(port_str) = remainder.strip_prefix(':') {
+            parse_port(port_str, kind)?
+        } else {
+            return Err(format!("invalid {kind} url: expected ':<port>' after ']'"));
+        };
+        return Ok(RemoteEndpoint {
+            host: host.to_string(),
+            port,
+        });
+    }
+
+    if input.contains(':') {
+        if input.matches(':').count() > 1 {
+            return Err(format!(
+                "invalid {kind} url: IPv6 host must be bracketed like [::1]:4532"
+            ));
+        }
+        let (host, port_str) = input
+            .rsplit_once(':')
+            .ok_or_else(|| format!("invalid {kind} url: expected host:port"))?;
+        if host.is_empty() {
+            return Err(format!("invalid {kind} url: host is empty"));
+        }
+        return Ok(RemoteEndpoint {
+            host: host.to_string(),
+            port: parse_port(port_str, kind)?,
+        });
+    }
+
+    Ok(RemoteEndpoint {
+        host: input.to_string(),
+        port: default_port,
+    })
+}
+
+fn parse_port(port_str: &str, kind: &str) -> Result<u16, String> {
+    let port: u16 = port_str
+        .parse()
+        .map_err(|_| format!("invalid {kind} port: '{port_str}'"))?;
+    if port == 0 {
+        return Err(format!("invalid {kind} port: 0"));
+    }
+    Ok(port)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse_remote_url_defaults_port() {
+        let ep = parse_remote_url("example.com").unwrap();
+        assert_eq!(ep.host, "example.com");
+        assert_eq!(ep.port, DEFAULT_REMOTE_PORT);
+    }
+
+    #[test]
+    fn test_parse_audio_url_defaults_port() {
+        let ep = parse_audio_url("example.com").unwrap();
+        assert_eq!(ep.port, DEFAULT_AUDIO_PORT);
+    }
+
+    #[test]
+    fn test_parse_strips_schemes() {
+        for url in &[
+            "tcp://host:9000",
+            "http-json://host:9000",
+            "audio://host:9000",
+        ] {
+            let ep = parse_remote_url(url).unwrap();
+            assert_eq!(ep.host, "host");
+            assert_eq!(ep.port, 9000);
+        }
+    }
+
+    #[test]
+    fn test_parse_bracketed_ipv6() {
+        let ep = parse_remote_url("[::1]:4532").unwrap();
+        assert_eq!(ep.host, "::1");
+        assert_eq!(ep.port, 4532);
+        assert_eq!(ep.connect_addr(), "[::1]:4532");
+    }
+
+    #[test]
+    fn test_parse_rejects_unbracketed_ipv6() {
+        assert!(parse_remote_url("::1:4532").is_err());
+    }
+
+    #[test]
+    fn test_parse_rejects_empty_host() {
+        assert!(parse_remote_url(":4530").is_err());
+    }
+
+    #[test]
+    fn test_parse_rejects_zero_port() {
+        assert!(parse_remote_url("host:0").is_err());
+    }
+
+    #[test]
+    fn test_parse_rejects_empty_url() {
+        assert!(parse_remote_url("   ").is_err());
+    }
+}

src/trx-configurator/Cargo.toml

@@ -15,7 +15,9 @@ path = "src/main.rs"
 clap = { workspace = true, features = ["derive"] }
 dialoguer = "0.11"
 tokio-serial = { workspace = true }
+toml = "0.8"
 toml_edit = "0.22"
+trx-config = { path = "../trx-config" }
 
 [dev-dependencies]
 tempfile = "3"

src/trx-configurator/src/check.rs

@@ -2,80 +2,37 @@
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+//! `trx-configurator --check`: run a config file through the same loader and
+//! validators the binaries use.
+//!
+//! This used to be a second, hand-maintained implementation — lists of known
+//! keys and a handful of re-implemented range checks — which drifted out of
+//! date as soon as a field was added.  It now defers entirely to `trx-config`,
+//! so a config that checks clean here is one the binaries will accept.
+
 use std::fmt::Write as _;
 use std::path::Path;
 
-use toml_edit::DocumentMut;
+use trx_config::{ClientConfig, ServerConfig};
 
-/// Known top-level keys for a standalone server config.
-const SERVER_KEYS: &[&str] = &[
-    "general",
+/// Top-level keys that only appear in a server config.  Used solely to guess
+/// what a section-less file is meant to be; the real key checking is done by
+/// the loader.
+const SERVER_MARKERS: &[&str] = &[
     "rig",
     "rigs",
-    "behavior",
     "listen",
-    "audio",
+    "behavior",
     "sdr",
     "pskreporter",
     "aprsfi",
     "decode_logs",
+    "timeouts",
+    "audio",
 ];
 
-/// Known top-level keys for a standalone client config.
-const CLIENT_KEYS: &[&str] = &["general", "remote", "remotes", "frontends"];
-
-/// Known top-level keys for a combined trx-rs.toml.
-const COMBINED_KEYS: &[&str] = &["trx-server", "trx-client"];
-
-/// Known sub-keys within [general] (server).
-const SERVER_GENERAL_KEYS: &[&str] = &["callsign", "log_level", "latitude", "longitude"];
-
-/// Known sub-keys within [general] (client).
-const CLIENT_GENERAL_KEYS: &[&str] = &[
-    "callsign",
-    "log_level",
-    "website_url",
-    "website_name",
-    "ais_vessel_url_base",
-];
-
-/// Known sub-keys within [rig].
-const RIG_KEYS: &[&str] = &["model", "initial_freq_hz", "initial_mode", "access"];
-
-/// Known sub-keys within [rig.access].
-const ACCESS_KEYS: &[&str] = &["type", "port", "baud", "host", "tcp_port", "args"];
-
-/// Known sub-keys within [listen].
-const LISTEN_KEYS: &[&str] = &["enabled", "listen", "port", "auth"];
-
-/// Known sub-keys within [audio] (server).
-const AUDIO_KEYS: &[&str] = &[
-    "enabled",
-    "listen",
-    "port",
-    "rx_enabled",
-    "tx_enabled",
-    "device",
-    "sample_rate",
-    "channels",
-    "frame_duration_ms",
-    "bitrate_bps",
-];
-
-/// Known sub-keys within [behavior].
-const BEHAVIOR_KEYS: &[&str] = &[
-    "poll_interval_ms",
-    "poll_interval_tx_ms",
-    "max_retries",
-    "retry_base_delay_ms",
-    "vfo_prime",
-];
-
-/// Known sub-keys within [remote].
-const REMOTE_KEYS: &[&str] = &["url", "rig_id", "auth", "poll_interval_ms"];
-
-/// Known sub-keys within [frontends].
-const FRONTENDS_KEYS: &[&str] = &["http", "rigctl", "http_json", "audio"];
+/// Top-level keys that only appear in a client config.
+const CLIENT_MARKERS: &[&str] = &["remote", "remotes", "frontends"];
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 enum DetectedType {
@@ -100,49 +57,38 @@ pub fn check_file(path: &Path) -> Result<String, String> {
     let content = std::fs::read_to_string(path)
         .map_err(|e| format!("Failed to read {}: {}", path.display(), e))?;
 
-    // Step 1: TOML syntax check
-    let doc: DocumentMut = content
-        .parse()
+    let table: toml::Table = toml::from_str(&content)
         .map_err(|e| format!("{}: TOML syntax error: {}", path.display(), e))?;
 
+    let detected = detect_type(&table);
+
     let mut report = String::new();
     let mut warnings: Vec<String> = Vec::new();
     let mut errors: Vec<String> = Vec::new();
 
-    let table = doc.as_table();
-
-    // Step 2: Detect config type
-    let detected = detect_type(table);
     writeln!(report, "{}: valid TOML", path.display()).unwrap();
     writeln!(report, "  Detected type: {}", detected).unwrap();
 
-    // Step 3: Structural validation
     match detected {
-        DetectedType::Server => {
-            check_unknown_keys(table, SERVER_KEYS, "", &mut warnings);
-            check_server_sections(table, "", &mut warnings, &mut errors);
-        }
-        DetectedType::Client => {
-            check_unknown_keys(table, CLIENT_KEYS, "", &mut warnings);
-            check_client_sections(table, "", &mut warnings, &mut errors);
-        }
+        DetectedType::Server => check_server(path, &mut warnings, &mut errors),
+        DetectedType::Client => check_client(path, &mut warnings, &mut errors),
         DetectedType::Combined => {
-            check_unknown_keys(table, COMBINED_KEYS, "", &mut warnings);
-            if let Some(server) = table.get("trx-server").and_then(|v| v.as_table()) {
-                check_unknown_keys(server, SERVER_KEYS, "[trx-server].", &mut warnings);
-                check_server_sections(server, "[trx-server].", &mut warnings, &mut errors);
+            if table.contains_key("trx-server") {
+                check_server(path, &mut warnings, &mut errors);
             }
-            if let Some(client) = table.get("trx-client").and_then(|v| v.as_table()) {
-                check_unknown_keys(client, CLIENT_KEYS, "[trx-client].", &mut warnings);
-                check_client_sections(client, "[trx-client].", &mut warnings, &mut errors);
+            if table.contains_key("trx-client") {
+                check_client(path, &mut warnings, &mut errors);
             }
         }
         DetectedType::Unknown => {
-            warnings.push("Could not detect config type. Expected server, client, or combined (trx-rs.toml) layout.".to_string());
+            warnings.push(
+                "Could not detect config type. Expected server, client, or combined \
+                 (trx-rs.toml) layout."
+                    .to_string(),
+            );
         }
     }
 
-    // Step 4: Format report
     for w in &warnings {
         writeln!(report, "  warning: {}", w).unwrap();
     }
@@ -169,23 +115,54 @@ pub fn check_file(path: &Path) -> Result<String, String> {
     }
 }
 
-fn detect_type(table: &toml_edit::Table) -> DetectedType {
+fn check_server(path: &Path, warnings: &mut Vec<String>, errors: &mut Vec<String>) {
+    match ServerConfig::load_from_file(path) {
+        Ok(loaded) => {
+            warnings.extend(loaded.unknown_keys.iter().map(|k| k.to_string()));
+            if let Err(e) = loaded.config.validate() {
+                errors.push(format!("[trx-server] {}", e));
+            }
+            errors.extend(
+                loaded
+                    .config
+                    .validate_sdr()
+                    .into_iter()
+                    .map(|e| format!("[trx-server] {}", e)),
+            );
+        }
+        Err(e) => errors.push(e.to_string()),
+    }
+}
+
+fn check_client(path: &Path, warnings: &mut Vec<String>, errors: &mut Vec<String>) {
+    match ClientConfig::load_from_file(path) {
+        Ok(loaded) => {
+            warnings.extend(loaded.unknown_keys.iter().map(|k| k.to_string()));
+            if let Err(e) = loaded.config.validate() {
+                errors.push(format!("[trx-client] {}", e));
+            }
+        }
+        Err(e) => errors.push(e.to_string()),
+    }
+}
+
+fn detect_type(table: &toml::Table) -> DetectedType {
     if table.contains_key("trx-server") || table.contains_key("trx-client") {
         return DetectedType::Combined;
     }
-    let keys: Vec<&str> = table.iter().map(|(k, _)| k).collect();
+    let keys: Vec<&str> = table.keys().map(|k| k.as_str()).collect();
 
-    let server_score = keys.iter().filter(|k| SERVER_KEYS.contains(k)).count();
-    let client_score = keys.iter().filter(|k| CLIENT_KEYS.contains(k)).count();
-
-    // Use distinguishing keys to break ties
-    if keys.contains(&"rig") || keys.contains(&"rigs") || keys.contains(&"listen") {
+    // Distinguishing keys first, then a simple majority.
+    if keys.iter().any(|k| ["rig", "rigs", "listen"].contains(k)) {
         return DetectedType::Server;
     }
-    if keys.contains(&"remote") || keys.contains(&"remotes") || keys.contains(&"frontends") {
+    if keys.iter().any(|k| CLIENT_MARKERS.contains(k)) {
         return DetectedType::Client;
     }
 
+    let server_score = keys.iter().filter(|k| SERVER_MARKERS.contains(k)).count();
+    let client_score = keys.iter().filter(|k| CLIENT_MARKERS.contains(k)).count();
+
     if server_score > client_score {
         DetectedType::Server
     } else if client_score > server_score {
@@ -197,194 +174,6 @@ fn detect_type(table: &toml_edit::Table) -> DetectedType {
     }
 }
 
-fn check_unknown_keys(
-    table: &toml_edit::Table,
-    known: &[&str],
-    prefix: &str,
-    warnings: &mut Vec<String>,
-) {
-    for (key, _) in table.iter() {
-        if !known.contains(&key) {
-            warnings.push(format!("{}unknown key '{}'", prefix, key));
-        }
-    }
-}
-
-fn check_server_sections(
-    table: &toml_edit::Table,
-    prefix: &str,
-    warnings: &mut Vec<String>,
-    errors: &mut Vec<String>,
-) {
-    if let Some(general) = table.get("general").and_then(|v| v.as_table()) {
-        check_unknown_keys(
-            general,
-            SERVER_GENERAL_KEYS,
-            &format!("{}[general].", prefix),
-            warnings,
-        );
-        validate_log_level(general, &format!("{}[general]", prefix), errors);
-        validate_coordinates(general, &format!("{}[general]", prefix), errors);
-    }
-
-    if let Some(rig) = table.get("rig").and_then(|v| v.as_table()) {
-        check_unknown_keys(rig, RIG_KEYS, &format!("{}[rig].", prefix), warnings);
-        if let Some(access) = rig.get("access").and_then(|v| v.as_table()) {
-            check_unknown_keys(
-                access,
-                ACCESS_KEYS,
-                &format!("{}[rig.access].", prefix),
-                warnings,
-            );
-            validate_access(access, &format!("{}[rig.access]", prefix), errors);
-        }
-    }
-
-    if let Some(listen) = table.get("listen").and_then(|v| v.as_table()) {
-        check_unknown_keys(
-            listen,
-            LISTEN_KEYS,
-            &format!("{}[listen].", prefix),
-            warnings,
-        );
-        validate_port(listen, "port", &format!("{}[listen]", prefix), errors);
-    }
-
-    if let Some(audio) = table.get("audio").and_then(|v| v.as_table()) {
-        check_unknown_keys(audio, AUDIO_KEYS, &format!("{}[audio].", prefix), warnings);
-        validate_port(audio, "port", &format!("{}[audio]", prefix), errors);
-    }
-
-    if let Some(behavior) = table.get("behavior").and_then(|v| v.as_table()) {
-        check_unknown_keys(
-            behavior,
-            BEHAVIOR_KEYS,
-            &format!("{}[behavior].", prefix),
-            warnings,
-        );
-    }
-}
-
-fn check_client_sections(
-    table: &toml_edit::Table,
-    prefix: &str,
-    warnings: &mut Vec<String>,
-    errors: &mut Vec<String>,
-) {
-    if let Some(general) = table.get("general").and_then(|v| v.as_table()) {
-        check_unknown_keys(
-            general,
-            CLIENT_GENERAL_KEYS,
-            &format!("{}[general].", prefix),
-            warnings,
-        );
-        validate_log_level(general, &format!("{}[general]", prefix), errors);
-    }
-
-    if let Some(remote) = table.get("remote").and_then(|v| v.as_table()) {
-        check_unknown_keys(
-            remote,
-            REMOTE_KEYS,
-            &format!("{}[remote].", prefix),
-            warnings,
-        );
-    }
-
-    if let Some(frontends) = table.get("frontends").and_then(|v| v.as_table()) {
-        check_unknown_keys(
-            frontends,
-            FRONTENDS_KEYS,
-            &format!("{}[frontends].", prefix),
-            warnings,
-        );
-        if let Some(http) = frontends.get("http").and_then(|v| v.as_table()) {
-            validate_port(http, "port", &format!("{}[frontends.http]", prefix), errors);
-        }
-        if let Some(rigctl) = frontends.get("rigctl").and_then(|v| v.as_table()) {
-            validate_port(
-                rigctl,
-                "port",
-                &format!("{}[frontends.rigctl]", prefix),
-                errors,
-            );
-        }
-    }
-}
-
-// ── Value validators ────────────────────────────────────────────────────
-
-fn validate_log_level(table: &toml_edit::Table, context: &str, errors: &mut Vec<String>) {
-    if let Some(level) = table.get("log_level").and_then(|v| v.as_str()) {
-        if !["trace", "debug", "info", "warn", "error"].contains(&level) {
-            errors.push(format!(
-                "{}.log_level '{}' is invalid (expected: trace, debug, info, warn, error)",
-                context, level
-            ));
-        }
-    }
-}
-
-fn validate_coordinates(table: &toml_edit::Table, context: &str, errors: &mut Vec<String>) {
-    if let Some(lat) = table
-        .get("latitude")
-        .and_then(|v| v.as_float().or_else(|| v.as_integer().map(|i| i as f64)))
-    {
-        if !(-90.0..=90.0).contains(&lat) {
-            errors.push(format!(
-                "{}.latitude {} is out of range (-90..90)",
-                context, lat
-            ));
-        }
-    }
-    if let Some(lon) = table
-        .get("longitude")
-        .and_then(|v| v.as_float().or_else(|| v.as_integer().map(|i| i as f64)))
-    {
-        if !(-180.0..=180.0).contains(&lon) {
-            errors.push(format!(
-                "{}.longitude {} is out of range (-180..180)",
-                context, lon
-            ));
-        }
-    }
-
-    let has_lat = table.contains_key("latitude");
-    let has_lon = table.contains_key("longitude");
-    if has_lat != has_lon {
-        errors.push(format!(
-            "{}: latitude and longitude must be set together or both omitted",
-            context
-        ));
-    }
-}
-
-fn validate_port(table: &toml_edit::Table, key: &str, context: &str, errors: &mut Vec<String>) {
-    if let Some(port) = table.get(key).and_then(|v| v.as_integer()) {
-        if let Some(enabled) = table.get("enabled").and_then(|v| v.as_bool()) {
-            if enabled && port <= 0 {
-                errors.push(format!("{}.{} must be > 0 when enabled", context, key));
-            }
-        }
-        if !(0..=65535).contains(&port) {
-            errors.push(format!(
-                "{}.{} {} is out of range (0..65535)",
-                context, key, port
-            ));
-        }
-    }
-}
-
-fn validate_access(table: &toml_edit::Table, context: &str, errors: &mut Vec<String>) {
-    if let Some(access_type) = table.get("type").and_then(|v| v.as_str()) {
-        if !["serial", "tcp", "sdr"].contains(&access_type) {
-            errors.push(format!(
-                "{}.type '{}' is invalid (expected: serial, tcp, sdr)",
-                context, access_type
-            ));
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -418,8 +207,7 @@ enabled = true
 port = 4530
 "#,
         );
-        assert!(result.is_ok());
-        let report = result.unwrap();
+        let report = result.expect("expected a clean report");
         assert!(report.contains("Detected type: server"));
         assert!(report.contains("No issues found"));
     }
@@ -432,41 +220,40 @@ port = 4530
 callsign = "W1AW"
 
 [remote]
-url = "localhost:4530"
+url = "192.168.1.10:4530"
 
 [frontends.http]
 enabled = true
 port = 8080
 "#,
         );
-        assert!(result.is_ok());
-        let report = result.unwrap();
+        let report = result.expect("expected a clean report");
         assert!(report.contains("Detected type: client"));
+        assert!(report.contains("No issues found"));
     }
 
     #[test]
     fn test_valid_combined_config() {
         let result = check_toml(
             r#"
-[trx-server.general]
-callsign = "W1AW"
-
-[trx-client.general]
-callsign = "W1AW"
+[trx-server.rig]
+model = "ft817"
+[trx-server.rig.access]
+type = "serial"
+port = "/dev/ttyUSB0"
+baud = 9600
 
 [trx-client.remote]
-url = "localhost:4530"
+url = "127.0.0.1:4530"
 "#,
         );
-        assert!(result.is_ok());
-        let report = result.unwrap();
+        let report = result.expect("expected a clean report");
         assert!(report.contains("Detected type: combined"));
     }
 
     #[test]
     fn test_invalid_toml_syntax() {
-        let result = check_toml("this is not [valid toml");
-        assert!(result.is_err());
+        let result = check_toml("[general\ncallsign = \"W1AW\"\n");
         assert!(result.unwrap_err().contains("TOML syntax error"));
     }
 
@@ -474,19 +261,22 @@ url = "localhost:4530"
     fn test_unknown_key_warning() {
         let result = check_toml(
             r#"
-[general]
-callsign = "W1AW"
-
 [rig]
 model = "ft817"
+[rig.access]
+type = "serial"
+port = "/dev/ttyUSB0"
+baud = 9600
 
-[bogus_section]
-foo = "bar"
+[listen]
+prot = 4530
 "#,
         );
-        assert!(result.is_ok());
-        let report = result.unwrap();
-        assert!(report.contains("unknown key 'bogus_section'"));
+        let report = result.expect("unknown keys are warnings, not errors");
+        assert!(
+            report.contains("unknown config key 'listen.prot' (did you mean 'listen.port'?)"),
+            "unexpected report: {report}"
+        );
     }
 
     #[test]
@@ -498,11 +288,13 @@ log_level = "verbose"
 
 [rig]
 model = "ft817"
+[rig.access]
+type = "serial"
+port = "/dev/ttyUSB0"
+baud = 9600
 "#,
         );
-        assert!(result.is_err());
-        let report = result.unwrap_err();
-        assert!(report.contains("log_level 'verbose' is invalid"));
+        assert!(result.unwrap_err().contains("log_level"));
     }
 
     #[test]
@@ -510,15 +302,17 @@ model = "ft817"
         let result = check_toml(
             r#"
 [general]
-latitude = 45.0
+latitude = 52.0
 
 [rig]
 model = "ft817"
+[rig.access]
+type = "serial"
+port = "/dev/ttyUSB0"
+baud = 9600
 "#,
         );
-        assert!(result.is_err());
-        let report = result.unwrap_err();
-        assert!(report.contains("latitude and longitude must be set together"));
+        assert!(result.unwrap_err().contains("longitude"));
     }
 
     #[test]
@@ -526,16 +320,18 @@ model = "ft817"
         let result = check_toml(
             r#"
 [general]
-latitude = 95.0
+latitude = 120.0
 longitude = 10.0
 
 [rig]
 model = "ft817"
+[rig.access]
+type = "serial"
+port = "/dev/ttyUSB0"
+baud = 9600
 "#,
         );
-        assert!(result.is_err());
-        let report = result.unwrap_err();
-        assert!(report.contains("latitude 95 is out of range"));
+        assert!(result.unwrap_err().contains("latitude"));
     }
 
     #[test]
@@ -547,10 +343,31 @@ model = "ft817"
 
 [rig.access]
 type = "usb"
+port = "/dev/ttyUSB0"
+baud = 9600
 "#,
         );
-        assert!(result.is_err());
-        let report = result.unwrap_err();
-        assert!(report.contains("type 'usb' is invalid"));
+        assert!(result.unwrap_err().contains("access"));
+    }
+
+    /// The old checker only knew a fixed list of top-level keys and a few range
+    /// rules, so it passed configs the server rejects at startup.
+    #[test]
+    fn test_catches_errors_the_key_list_checker_missed() {
+        let result = check_toml(
+            r#"
+[rig]
+model = "ft817"
+[rig.access]
+type = "serial"
+port = "/dev/ttyUSB0"
+baud = 9600
+
+[audio]
+enabled = true
+frame_duration_ms = 7
+"#,
+        );
+        assert!(result.unwrap_err().contains("frame_duration_ms"));
     }
 }

src/trx-configurator/src/writer.rs

@@ -211,10 +211,13 @@ pub fn build_server(general: ServerGeneral, rig: RigSetup, listen: ListenSetup)
     let mut doc = DocumentMut::new();
     doc.decor_mut()
         .set_prefix("# trx-server configuration\n# Generated by trx-configurator\n");
-    let tables = build_server_tables(general, rig, listen);
-    for (key, item) in tables.iter() {
-        doc.insert(key, item.clone());
-    }
+    // Emit the sectioned shape (`[trx-server]`) that trx-server writes with
+    // --print-config, so a generated file can be dropped into a combined
+    // trx-rs.toml unchanged.
+    doc.insert(
+        "trx-server",
+        Item::Table(build_server_tables(general, rig, listen)),
+    );
     doc
 }
 
@@ -350,10 +353,10 @@ pub fn build_client(
     let mut doc = DocumentMut::new();
     doc.decor_mut()
         .set_prefix("# trx-client configuration\n# Generated by trx-configurator\n");
-    let tables = build_client_tables(general, remote, frontends);
-    for (key, item) in tables.iter() {
-        doc.insert(key, item.clone());
-    }
+    doc.insert(
+        "trx-client",
+        Item::Table(build_client_tables(general, remote, frontends)),
+    );
     doc
 }
 
@@ -453,3 +456,60 @@ pub fn write_file(doc: &DocumentMut, path: &Path) -> Result<(), String> {
     println!("Wrote {}", path.display());
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use trx_config::{ClientConfig, ServerConfig};
+
+    fn write_temp(doc: &DocumentMut) -> tempfile::NamedTempFile {
+        let file = tempfile::Builder::new().suffix(".toml").tempfile().unwrap();
+        std::fs::write(file.path(), doc.to_string()).unwrap();
+        file
+    }
+
+    /// The wizard used to emit root-level `[general]` / `[rig]` tables while the
+    /// loader demanded a `[trx-server]` section, so every generated standalone
+    /// config was rejected by the binary it was generated for.
+    #[test]
+    fn test_generated_server_config_loads_and_validates() {
+        let file = write_temp(&build_default(ConfigType::Server));
+        let cfg = ServerConfig::load_from_file(file.path())
+            .expect("generated config must load")
+            .config;
+        cfg.validate().expect("generated config must validate");
+        assert_eq!(cfg.rig.model.as_deref(), Some("ft817"));
+        assert_eq!(cfg.listen.port, 4530);
+    }
+
+    #[test]
+    fn test_generated_client_config_loads_and_validates() {
+        let file = write_temp(&build_default(ConfigType::Client));
+        let cfg = ClientConfig::load_from_file(file.path())
+            .expect("generated config must load")
+            .config;
+        cfg.validate().expect("generated config must validate");
+        assert_eq!(cfg.remote.url.as_deref(), Some("localhost:4530"));
+    }
+
+    #[test]
+    fn test_generated_combined_config_loads_both_sections() {
+        let file = write_temp(&build_default(ConfigType::Combined));
+        let server = ServerConfig::load_from_file(file.path())
+            .expect("server section must load")
+            .config;
+        server.validate().expect("server section must validate");
+        let client = ClientConfig::load_from_file(file.path())
+            .expect("client section must load")
+            .config;
+        client.validate().expect("client section must validate");
+    }
+
+    #[test]
+    fn test_generated_docs_are_sectioned() {
+        let doc = build_default(ConfigType::Server);
+        assert!(doc.as_table().contains_key("trx-server"));
+        let doc = build_default(ConfigType::Client);
+        assert!(doc.as_table().contains_key("trx-client"));
+    }
+}

src/trx-core/Cargo.toml

@@ -17,3 +17,4 @@ uuid = { workspace = true }
 ts-rs = { version = "12.0.1", features = ["uuid-impl"] }
 sgp4 = "2"
 reqwest = { version = "0.12", default-features = false, features = ["rustls-tls"] }
+base64 = "0.22"

src/trx-core/src/audio.rs

@@ -74,6 +74,11 @@ pub const AUDIO_MSG_LRPT_PROGRESS: u8 = 0x18;
 pub const AUDIO_MSG_WEFAX_DECODE: u8 = 0x19;
 /// Server → client: WEFAX decode progress (JSON `DecodedMessage::WefaxProgress`).
 pub const AUDIO_MSG_WEFAX_PROGRESS: u8 = 0x1A;
+/// Server → client: SSTV received picture (JSON `DecodedMessage::Sstv`).
+pub const AUDIO_MSG_SSTV_DECODE: u8 = 0x1B;
+/// Server → client: SSTV decode progress, one line at a time
+/// (JSON `DecodedMessage::SstvProgress`).
+pub const AUDIO_MSG_SSTV_PROGRESS: u8 = 0x1C;
 
 /// Maximum payload size for normal messages (1 MB).
 const MAX_PAYLOAD_SIZE: u32 = 1_048_576;

src/trx-core/src/decode.rs

@@ -36,6 +36,10 @@ pub enum DecodedMessage {
     Wefax(WefaxMessage),
     #[serde(rename = "wefax_progress")]
     WefaxProgress(WefaxProgress),
+    #[serde(rename = "sstv")]
+    Sstv(SstvMessage),
+    #[serde(rename = "sstv_progress")]
+    SstvProgress(SstvProgress),
 }
 
 impl DecodedMessage {
@@ -52,6 +56,8 @@ impl DecodedMessage {
             Self::LrptProgress(m) => m.rig_id = Some(id),
             Self::Wefax(m) => m.rig_id = Some(id),
             Self::WefaxProgress(m) => m.rig_id = Some(id),
+            Self::Sstv(m) => m.rig_id = Some(id),
+            Self::SstvProgress(m) => m.rig_id = Some(id),
         }
     }
 
@@ -68,6 +74,8 @@ impl DecodedMessage {
             Self::LrptProgress(m) => m.rig_id.as_deref(),
             Self::Wefax(m) => m.rig_id.as_deref(),
             Self::WefaxProgress(m) => m.rig_id.as_deref(),
+            Self::Sstv(m) => m.rig_id.as_deref(),
+            Self::SstvProgress(m) => m.rig_id.as_deref(),
         }
     }
 }
@@ -319,3 +327,52 @@ pub struct WefaxProgress {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub state: Option<String>,
 }
+
+/// A received SSTV picture, complete or cut short.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SstvMessage {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rig_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub ts_ms: Option<i64>,
+    /// VIS code the transmission announced itself with.
+    pub vis: u8,
+    /// Mode name, e.g. "Martin M1".
+    pub mode: String,
+    pub width: u16,
+    pub height: u16,
+    /// Image lines actually received, which is the height only if the whole
+    /// frame arrived.
+    pub lines: u16,
+    /// Whether reception reached the bottom of the frame.
+    pub complete: bool,
+    /// Filesystem path to the saved PNG, when one was written.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub path: Option<String>,
+    /// Base64-encoded PNG for the trip to a client. Populated when sending and
+    /// stripped before the message is stored in history, which would otherwise
+    /// hold a megabyte per picture.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub png_data: Option<String>,
+}
+
+/// A picture arriving, emitted per line so it can be watched.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SstvProgress {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rig_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub ts_ms: Option<i64>,
+    pub vis: u8,
+    pub mode: String,
+    pub width: u16,
+    pub height: u16,
+    /// Index of the line this update carries.
+    pub line: u16,
+    /// Base64-encoded RGB triples for that one line.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub line_data: Option<String>,
+    /// Decoder state for display, e.g. "Receiving Martin M1".
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub state: Option<String>,
+}

src/trx-core/src/rig/command.rs

@@ -33,6 +33,7 @@ pub enum RigCommand {
     SetWsprDecodeEnabled(bool),
     SetLrptDecodeEnabled(bool),
     SetWefaxDecodeEnabled(bool),
+    SetSstvDecodeEnabled(bool),
     ResetAprsDecoder,
     ResetHfAprsDecoder,
     ResetCwDecoder,
@@ -42,6 +43,7 @@ pub enum RigCommand {
     ResetWsprDecoder,
     ResetLrptDecoder,
     ResetWefaxDecoder,
+    ResetSstvDecoder,
     SetBandwidth(u32),
     SetSdrGain(f64),
     SetSdrLnaGain(f64),

src/trx-core/src/rig/controller/handlers.rs

@@ -462,6 +462,8 @@ pub fn command_from_rig_command(cmd: RigCommand) -> Box<dyn RigCommandHandler> {
         | RigCommand::ResetLrptDecoder
         | RigCommand::SetWefaxDecodeEnabled(_)
         | RigCommand::ResetWefaxDecoder
+        | RigCommand::SetSstvDecodeEnabled(_)
+        | RigCommand::ResetSstvDecoder
         | RigCommand::SetBandwidth(_)
         | RigCommand::SetSdrGain(_)
         | RigCommand::SetSdrLnaGain(_)

src/trx-core/src/rig/mod.rs

@@ -19,6 +19,7 @@ pub mod command;
 pub mod controller;
 pub mod request;
 pub mod response;
+pub mod spectrum_wire;
 pub mod state;
 
 /// How this backend communicates with the rig.

src/trx-core/src/rig/spectrum_wire.rs

@@ -0,0 +1,124 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Compact wire encoding for spectrum bins.
+//!
+//! Bins are dBFS magnitudes, and the web UI has always drawn them from `i8`
+//! values — the SSE hop to the browser quantizes and base64-encodes them. The
+//! server→client hop, which is the one that crosses the operator's network,
+//! used to send the same information as a JSON array of `f32`: around ten bytes
+//! per bin instead of one, or roughly 10 KB per 1024-bin frame.
+//!
+//! Bins therefore travel as base64-encoded `i8` dBFS, about an eighth of the
+//! size, at a resolution the display already rounds to. Decoding still accepts
+//! the old array form, so a new client can read an older server.
+
+use base64::engine::general_purpose::STANDARD as BASE64;
+use base64::Engine as _;
+use serde::de::{SeqAccess, Visitor};
+use serde::{Deserializer, Serializer};
+use std::fmt;
+
+/// Quantize to whole dBFS and encode as base64.
+pub fn serialize<S: Serializer>(bins: &[f32], serializer: S) -> Result<S::Ok, S::Error> {
+    let quantized: Vec<u8> = bins
+        .iter()
+        .map(|&db| {
+            let clamped = if db.is_finite() { db } else { -128.0 };
+            clamped.round().clamp(-128.0, 127.0) as i8 as u8
+        })
+        .collect();
+    serializer.serialize_str(&BASE64.encode(quantized))
+}
+
+/// Decode base64 bins, or a plain array of numbers from an older server.
+pub fn deserialize<'de, D: Deserializer<'de>>(deserializer: D) -> Result<Vec<f32>, D::Error> {
+    deserializer.deserialize_any(BinsVisitor)
+}
+
+struct BinsVisitor;
+
+impl<'de> Visitor<'de> for BinsVisitor {
+    type Value = Vec<f32>;
+
+    fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("base64-encoded i8 dBFS bins, or an array of numbers")
+    }
+
+    fn visit_str<E: serde::de::Error>(self, value: &str) -> Result<Self::Value, E> {
+        let bytes = BASE64
+            .decode(value)
+            .map_err(|e| E::custom(format!("invalid base64 spectrum bins: {e}")))?;
+        Ok(bytes.into_iter().map(|byte| byte as i8 as f32).collect())
+    }
+
+    fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
+        let mut bins = Vec::with_capacity(seq.size_hint().unwrap_or(1024));
+        while let Some(value) = seq.next_element::<f32>()? {
+            bins.push(value);
+        }
+        Ok(bins)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use serde::{Deserialize, Serialize};
+
+    #[derive(Debug, Serialize, Deserialize, PartialEq)]
+    struct Frame {
+        #[serde(with = "super")]
+        bins: Vec<f32>,
+    }
+
+    #[test]
+    fn test_round_trip_quantizes_to_whole_db() {
+        let frame = Frame {
+            bins: vec![-73.4, -20.6, 0.0, -120.2],
+        };
+        let json = serde_json::to_string(&frame).unwrap();
+        let back: Frame = serde_json::from_str(&json).unwrap();
+        assert_eq!(back.bins, vec![-73.0, -21.0, 0.0, -120.0]);
+    }
+
+    #[test]
+    fn test_serializes_as_a_base64_string() {
+        let json = serde_json::to_string(&Frame {
+            bins: vec![-1.0, 0.0],
+        })
+        .unwrap();
+        assert!(json.contains('"'), "bins should be a string: {json}");
+        assert!(!json.contains('['), "bins should not be an array: {json}");
+    }
+
+    #[test]
+    fn test_clamps_out_of_range_and_non_finite() {
+        let frame = Frame {
+            bins: vec![-400.0, 400.0, f32::NAN, f32::NEG_INFINITY],
+        };
+        let json = serde_json::to_string(&frame).unwrap();
+        let back: Frame = serde_json::from_str(&json).unwrap();
+        assert_eq!(back.bins, vec![-128.0, 127.0, -128.0, -128.0]);
+    }
+
+    #[test]
+    fn test_reads_the_old_array_form() {
+        let back: Frame = serde_json::from_str(r#"{"bins":[-73.25,-20.5]}"#).unwrap();
+        assert_eq!(back.bins, vec![-73.25, -20.5]);
+    }
+
+    /// The point of the change: an ordinary frame gets much smaller.
+    #[test]
+    fn test_frame_is_far_smaller_than_the_array_form() {
+        let bins: Vec<f32> = (0..1024).map(|i| -60.0 - (i % 40) as f32 * 0.37).collect();
+        let compact = serde_json::to_string(&Frame { bins: bins.clone() }).unwrap();
+        let verbose = serde_json::to_string(&bins).unwrap();
+        assert!(
+            compact.len() * 5 < verbose.len(),
+            "compact {} bytes vs array {} bytes",
+            compact.len(),
+            verbose.len()
+        );
+    }
+}

src/trx-core/src/rig/state.rs

@@ -34,6 +34,8 @@ pub struct DecoderConfig {
     #[serde(default)]
     pub wefax_decode_enabled: bool,
     #[serde(default)]
+    pub sstv_decode_enabled: bool,
+    #[serde(default)]
     pub recorder_enabled: bool,
 }
 
@@ -62,6 +64,8 @@ pub struct DecoderResetSeqs {
     pub lrpt_decode_reset_seq: u64,
     #[serde(default, skip_serializing)]
     pub wefax_decode_reset_seq: u64,
+    #[serde(default, skip_serializing)]
+    pub sstv_decode_reset_seq: u64,
 }
 
 /// Simple transceiver state representation held by the rig task.
@@ -390,6 +394,12 @@ fn default_wfm_denoise_level() -> WfmDenoiseLevel {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, TS)]
 pub struct SpectrumData {
     /// FFT magnitude bins in dBFS, FFT-shifted so DC (centre frequency) is at index N/2.
+    ///
+    /// On the wire these are base64-encoded `i8` whole dBFS (see
+    /// `spectrum_wire`), which is what the display draws anyway; the TypeScript
+    /// type describes the decoded array the browser receives over SSE.
+    #[serde(with = "crate::rig::spectrum_wire")]
+    #[ts(type = "Array<number>")]
     pub bins: Vec<f32>,
     /// Centre frequency of the SDR capture in Hz.
     #[ts(type = "number")]

src/trx-protocol/src/decoders.rs

@@ -139,6 +139,16 @@ pub const DECODER_REGISTRY: &[DecoderDescriptor] = &[
         background_decode: false,
         bookmark_selectable: true,
     },
+    DecoderDescriptor {
+        id: "sstv",
+        label: "SSTV",
+        activation: DecoderActivation::Toggle,
+        // SSTV is sent on sideband on HF and on FM simplex on VHF, and the
+        // decoder cares only about the audio it is handed.
+        active_modes: &["USB", "LSB", "FM", "AM", "DIG"],
+        background_decode: false,
+        bookmark_selectable: true,
+    },
 ];
 
 // ============================================================================

src/trx-protocol/src/lib.rs

@@ -18,4 +18,6 @@ pub use auth::{NoAuthValidator, SimpleTokenValidator, TokenValidator};
 pub use codec::{mode_to_string, parse_envelope, parse_mode};
 pub use decoders::{DecoderActivation, DecoderDescriptor, DECODER_REGISTRY};
 pub use mapping::{client_command_to_rig, rig_command_to_client};
-pub use types::{ClientCommand, ClientEnvelope, ClientResponse, MeterUpdate, RigEntry};
+pub use types::{
+    ClientCommand, ClientEnvelope, ClientResponse, MeterUpdate, RigEntry, SpectrumFrame,
+};

src/trx-protocol/src/mapping.rs

@@ -102,7 +102,7 @@ macro_rules! define_command_mapping {
 
 define_command_mapping! {
     // ── Client-only variants (no RigCommand counterpart) ─────────────
-    client_only: GetRigs, GetSatPasses, SubscribeMeter;
+    client_only: GetRigs, GetSatPasses, SubscribeMeter, SubscribeSpectrum;
 
     // ── Unit variants (no payload) ───────────────────────────────────
     unit:
@@ -122,7 +122,8 @@ define_command_mapping! {
         ResetFt2Decoder      <=> ResetFt2Decoder,
         ResetWsprDecoder     <=> ResetWsprDecoder,
         ResetLrptDecoder     <=> ResetLrptDecoder,
-        ResetWefaxDecoder    <=> ResetWefaxDecoder;
+        ResetWefaxDecoder    <=> ResetWefaxDecoder,
+        ResetSstvDecoder     <=> ResetSstvDecoder;
 
     // ── Single-field struct <=> tuple ────────────────────────────────
     field:
@@ -140,6 +141,7 @@ define_command_mapping! {
         SetWsprDecodeEnabled  { enabled }        <=> SetWsprDecodeEnabled,
         SetLrptDecodeEnabled  { enabled }        <=> SetLrptDecodeEnabled,
         SetWefaxDecodeEnabled { enabled }        <=> SetWefaxDecodeEnabled,
+        SetSstvDecodeEnabled  { enabled }        <=> SetSstvDecodeEnabled,
         SetBandwidth          { bandwidth_hz }   <=> SetBandwidth,
         SetSdrGain            { gain_db }        <=> SetSdrGain,
         SetSdrLnaGain         { gain_db }        <=> SetSdrLnaGain,

src/trx-protocol/src/types.rs

@@ -73,6 +73,9 @@ pub enum ClientCommand {
     SetWefaxDecodeEnabled {
         enabled: bool,
     },
+    SetSstvDecodeEnabled {
+        enabled: bool,
+    },
     ResetAprsDecoder,
     ResetHfAprsDecoder,
     ResetCwDecoder,
@@ -82,6 +85,7 @@ pub enum ClientCommand {
     ResetWsprDecoder,
     ResetLrptDecoder,
     ResetWefaxDecoder,
+    ResetSstvDecoder,
     SetBandwidth {
         bandwidth_hz: u32,
     },
@@ -126,6 +130,28 @@ pub enum ClientCommand {
     /// newline-delimited `MeterUpdate` JSON frames and no further commands or
     /// regular responses are sent.  Intended for a dedicated TCP connection.
     SubscribeMeter,
+    /// Subscribe to a per-rig spectrum stream on this connection.  Like
+    /// `SubscribeMeter`, the connection becomes a one-way flow of
+    /// newline-delimited `SpectrumFrame` JSON and no further commands or
+    /// regular responses are sent.
+    ///
+    /// Polling `GetSpectrum` costs a round trip per frame, which caps the frame
+    /// rate at 1/RTT no matter how often the client asks; the server pushes at
+    /// its own cadence instead.  Clients fall back to polling when the server
+    /// rejects this command.
+    SubscribeSpectrum,
+}
+
+/// One spectrum frame pushed by the server on a dedicated spectrum stream.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct SpectrumFrame {
+    /// Rig identifier this frame belongs to.
+    pub rig_id: String,
+    /// The frame itself; bins travel base64-encoded (see `spectrum_wire`).
+    pub spectrum: trx_core::rig::state::SpectrumData,
+    /// Virtual-channel RDS state, mirroring what `GetSpectrum` returned.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub vchan_rds: Option<Vec<trx_core::rig::state::VchanRdsEntry>>,
 }
 
 /// Fast meter sample pushed by the server on a dedicated meter stream.

src/trx-server/Cargo.toml

@@ -32,6 +32,7 @@ cpal = "0.15"
 num-complex = "0.4"
 opus = "0.3"
 trx-app = { path = "../trx-app" }
+trx-config = { path = "../trx-config" }
 trx-backend = { path = "trx-backend", features = ["soapysdr"] }
 trx-ais = { path = "../decoders/trx-ais" }
 trx-vdes = { path = "../decoders/trx-vdes" }
@@ -41,6 +42,7 @@ trx-cw = { path = "../decoders/trx-cw" }
 trx-decode-log = { path = "../decoders/trx-decode-log" }
 trx-ftx = { path = "../decoders/trx-ftx" }
 trx-wefax = { path = "../decoders/trx-wefax" }
+trx-sstv = { path = "../decoders/trx-sstv" }
 trx-wspr = { path = "../decoders/trx-wspr" }
 trx-wxsat = { path = "../decoders/trx-wxsat" }
 trx-protocol = { path = "../trx-protocol" }

src/trx-server/src/audio.rs

@@ -30,10 +30,11 @@ use trx_core::audio::{
     write_vchan_uuid_msg, AudioStreamInfo, AUDIO_MSG_AIS_DECODE, AUDIO_MSG_APRS_DECODE,
     AUDIO_MSG_CW_DECODE, AUDIO_MSG_FT2_DECODE, AUDIO_MSG_FT4_DECODE, AUDIO_MSG_FT8_DECODE,
     AUDIO_MSG_HF_APRS_DECODE, AUDIO_MSG_HISTORY_COMPRESSED, AUDIO_MSG_LRPT_IMAGE,
-    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_STREAM_INFO, AUDIO_MSG_TX_FRAME,
-    AUDIO_MSG_VCHAN_ALLOCATED, AUDIO_MSG_VCHAN_BW, AUDIO_MSG_VCHAN_DESTROYED, AUDIO_MSG_VCHAN_FREQ,
-    AUDIO_MSG_VCHAN_MODE, AUDIO_MSG_VCHAN_REMOVE, AUDIO_MSG_VCHAN_SUB, AUDIO_MSG_VCHAN_UNSUB,
-    AUDIO_MSG_VDES_DECODE, AUDIO_MSG_WEFAX_DECODE, AUDIO_MSG_WEFAX_PROGRESS, AUDIO_MSG_WSPR_DECODE,
+    AUDIO_MSG_LRPT_PROGRESS, AUDIO_MSG_RX_FRAME, AUDIO_MSG_SSTV_DECODE, AUDIO_MSG_SSTV_PROGRESS,
+    AUDIO_MSG_STREAM_INFO, AUDIO_MSG_TX_FRAME, AUDIO_MSG_VCHAN_ALLOCATED, AUDIO_MSG_VCHAN_BW,
+    AUDIO_MSG_VCHAN_DESTROYED, AUDIO_MSG_VCHAN_FREQ, AUDIO_MSG_VCHAN_MODE, AUDIO_MSG_VCHAN_REMOVE,
+    AUDIO_MSG_VCHAN_SUB, AUDIO_MSG_VCHAN_UNSUB, AUDIO_MSG_VDES_DECODE, AUDIO_MSG_WEFAX_DECODE,
+    AUDIO_MSG_WEFAX_PROGRESS, AUDIO_MSG_WSPR_DECODE,
 };
 #[cfg(test)]
 use trx_core::decode::{AisMessage, AprsPacket, CwEvent};
@@ -292,6 +293,11 @@ fn build_history_blob(histories: &DecoderHistories) -> (Vec<u8>, usize) {
         DecodedMessage::Wefax,
         AUDIO_MSG_WEFAX_DECODE
     );
+    push_history!(
+        histories.snapshot_sstv_history(),
+        DecodedMessage::Sstv,
+        AUDIO_MSG_SSTV_DECODE
+    );
 
     (blob, count)
 }
@@ -2285,15 +2291,12 @@ pub async fn run_wefax_decoder(
     mut state_rx: watch::Receiver<RigState>,
     decode_tx: broadcast::Sender<DecodedMessage>,
     histories: Arc<DecoderHistories>,
+    wefax_output_dir: std::path::PathBuf,
 ) {
     use trx_wefax::{WefaxConfig, WefaxDecoder, WefaxEvent};
 
     info!("WEFAX decoder started ({}Hz, {} ch)", sample_rate, channels);
 
-    let wefax_output_dir = dirs::cache_dir()
-        .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
-        .join("trx-rs")
-        .join("wefax");
     let config = WefaxConfig {
         output_dir: Some(wefax_output_dir.to_string_lossy().into_owned()),
         ..WefaxConfig::default()
@@ -2444,6 +2447,244 @@ pub async fn run_wefax_decoder(
     info!("WEFAX decoder stopped");
 }
 
+// ---------------------------------------------------------------------------
+// SSTV decoder task
+// ---------------------------------------------------------------------------
+
+/// Turn a decoded picture into the message clients receive, saving the PNG on
+/// the way. The picture travels as base64 so a client on another machine has
+/// it without a second request; the server keeps its own copy on disk.
+fn sstv_message(
+    image: &trx_sstv::SstvImage,
+    output_dir: &std::path::Path,
+    freq_hz: u64,
+) -> DecodedMessage {
+    let path = match image.save_png(output_dir, freq_hz) {
+        Ok(path) => Some(path.to_string_lossy().into_owned()),
+        Err(e) => {
+            warn!("SSTV: failed to save image: {}", e);
+            None
+        }
+    };
+    let png_data = image.to_png_base64().ok();
+    DecodedMessage::Sstv(trx_core::decode::SstvMessage {
+        rig_id: None,
+        ts_ms: Some(image.started_ms),
+        vis: image.vis,
+        mode: image.mode.to_string(),
+        width: image.width,
+        height: image.height,
+        lines: image.lines,
+        complete: image.complete,
+        path,
+        png_data,
+    })
+}
+
+/// Run the SSTV decoder task. Processes PCM when enabled and the rig mode is
+/// one SSTV is sent in.
+#[allow(clippy::too_many_arguments)]
+pub async fn run_sstv_decoder(
+    sample_rate: u32,
+    channels: u16,
+    mut pcm_rx: broadcast::Receiver<Vec<f32>>,
+    mut state_rx: watch::Receiver<RigState>,
+    decode_tx: broadcast::Sender<DecodedMessage>,
+    histories: Arc<DecoderHistories>,
+    output_dir: std::path::PathBuf,
+) {
+    use trx_sstv::{SstvConfig, SstvDecoder, SstvEvent};
+
+    info!("SSTV decoder started ({}Hz, {} ch)", sample_rate, channels);
+
+    let mut decoder = SstvDecoder::new(sample_rate, SstvConfig::default());
+    let mut was_active = false;
+    let mut last_reset_seq: u64 = 0;
+
+    let is_sstv_mode = |mode: &RigMode| {
+        matches!(
+            mode,
+            RigMode::USB | RigMode::LSB | RigMode::FM | RigMode::AM | RigMode::DIG
+        )
+    };
+
+    // Reset returns any picture in progress rather than discarding it: a
+    // half-received frame is still worth keeping.
+    macro_rules! flush {
+        ($decoder:expr) => {
+            for event in $decoder.reset() {
+                if let SstvEvent::Complete(image) = event {
+                    // Read the dial now rather than caching it: the picture is
+                    // named for where it was received.
+                    let freq_hz = state_rx.borrow().status.freq.hz;
+                    let msg = sstv_message(&image, &output_dir, freq_hz);
+                    if let DecodedMessage::Sstv(ref stored) = msg {
+                        histories.record_sstv_message(stored.clone());
+                    }
+                    let _ = decode_tx.send(msg);
+                }
+            }
+        };
+    }
+
+    let mut active = state_rx.borrow().decoders.sstv_decode_enabled
+        && is_sstv_mode(&state_rx.borrow().status.mode);
+
+    loop {
+        if !active {
+            match state_rx.changed().await {
+                Ok(()) => {
+                    let state = state_rx.borrow();
+                    active = state.decoders.sstv_decode_enabled && is_sstv_mode(&state.status.mode);
+                    if active {
+                        pcm_rx = pcm_rx.resubscribe();
+                    }
+                }
+                Err(_) => break,
+            }
+            continue;
+        }
+
+        tokio::select! {
+            recv = pcm_rx.recv() => {
+                match recv {
+                    Ok(frame) => {
+                        let (process_enabled, reset_seq) = {
+                            let state = state_rx.borrow();
+                            (
+                                state.decoders.sstv_decode_enabled
+                                    && is_sstv_mode(&state.status.mode),
+                                state.reset_seqs.sstv_decode_reset_seq,
+                            )
+                        };
+
+                        if reset_seq != last_reset_seq {
+                            last_reset_seq = reset_seq;
+                            flush!(decoder);
+                            info!("SSTV decoder reset (seq={})", last_reset_seq);
+                            pcm_rx = pcm_rx.resubscribe();
+                            continue;
+                        }
+
+                        if !process_enabled {
+                            if was_active {
+                                flush!(decoder);
+                                was_active = false;
+                            }
+                            active = false;
+                            continue;
+                        }
+
+                        let mono = if channels > 1 {
+                            let num_frames = frame.len() / channels as usize;
+                            let mut mono = Vec::with_capacity(num_frames);
+                            for i in 0..num_frames {
+                                mono.push(frame[i * channels as usize]);
+                            }
+                            mono
+                        } else {
+                            frame
+                        };
+
+                        was_active = true;
+                        let events = tokio::task::block_in_place(|| {
+                            let _span = info_span!("sstv_decode").entered();
+                            decoder.process_samples(&mono)
+                        });
+
+                        let latest_reset_seq = state_rx.borrow().reset_seqs.sstv_decode_reset_seq;
+                        if latest_reset_seq != reset_seq {
+                            last_reset_seq = latest_reset_seq;
+                            flush!(decoder);
+                            info!("SSTV decoder reset (seq={})", last_reset_seq);
+                            pcm_rx = pcm_rx.resubscribe();
+                            continue;
+                        }
+
+                        for event in events {
+                            match event {
+                                SstvEvent::Started { vis, mode, width, height } => {
+                                    info!("SSTV: receiving {} (VIS {})", mode, vis);
+                                    let _ = decode_tx.send(DecodedMessage::SstvProgress(
+                                        trx_core::decode::SstvProgress {
+                                            rig_id: None,
+                                            ts_ms: Some(now_ms()),
+                                            vis,
+                                            mode: mode.to_string(),
+                                            width,
+                                            height,
+                                            line: 0,
+                                            line_data: None,
+                                            state: Some(format!("Receiving {mode}")),
+                                        },
+                                    ));
+                                }
+                                SstvEvent::Row { line, rgb } => {
+                                    // One row per message: the picture is meant
+                                    // to be watched arriving, and a row of a
+                                    // 640-wide mode is under 2 kB.
+                                    let _ = decode_tx.send(DecodedMessage::SstvProgress(
+                                        trx_core::decode::SstvProgress {
+                                            rig_id: None,
+                                            ts_ms: Some(now_ms()),
+                                            vis: 0,
+                                            mode: String::new(),
+                                            width: 0,
+                                            height: 0,
+                                            line,
+                                            line_data: Some({
+                                                use base64::Engine as _;
+                                                base64::engine::general_purpose::STANDARD
+                                                    .encode(&rgb)
+                                            }),
+                                            state: None,
+                                        },
+                                    ));
+                                }
+                                SstvEvent::Complete(image) => {
+                                    info!(
+                                        "SSTV: {} picture, {} of {} lines",
+                                        image.mode, image.lines, image.height
+                                    );
+                                    let freq_hz = state_rx.borrow().status.freq.hz;
+                                    let msg = sstv_message(&image, &output_dir, freq_hz);
+                                    if let DecodedMessage::Sstv(ref stored) = msg {
+                                        histories.record_sstv_message(stored.clone());
+                                    }
+                                    let _ = decode_tx.send(msg);
+                                }
+                            }
+                        }
+                    }
+                    Err(broadcast::error::RecvError::Lagged(n)) => {
+                        warn!("SSTV decoder: dropped {} PCM frames", n);
+                    }
+                    Err(broadcast::error::RecvError::Closed) => break,
+                }
+            }
+            changed = state_rx.changed() => {
+                match changed {
+                    Ok(()) => {
+                        let state = state_rx.borrow();
+                        active = state.decoders.sstv_decode_enabled
+                            && is_sstv_mode(&state.status.mode);
+                    }
+                    Err(_) => break,
+                }
+            }
+        }
+    }
+    info!("SSTV decoder stopped");
+}
+
+/// Milliseconds since the epoch.
+fn now_ms() -> i64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_millis() as i64
+}
+
 // ---------------------------------------------------------------------------
 // Virtual-channel audio support
 // ---------------------------------------------------------------------------
@@ -3078,6 +3319,8 @@ async fn handle_audio_client(
                                 DecodedMessage::LrptProgress(_) => AUDIO_MSG_LRPT_PROGRESS,
                                 DecodedMessage::Wefax(_) => AUDIO_MSG_WEFAX_DECODE,
                                 DecodedMessage::WefaxProgress(_) => AUDIO_MSG_WEFAX_PROGRESS,
+                                DecodedMessage::Sstv(_) => AUDIO_MSG_SSTV_DECODE,
+                                DecodedMessage::SstvProgress(_) => AUDIO_MSG_SSTV_PROGRESS,
                             };
                             if let Ok(json) = serde_json::to_vec(&msg) {
                                 if let Err(e) = write_audio_msg(&mut writer_for_rx, msg_type, &json).await {
@@ -3110,6 +3353,8 @@ async fn handle_audio_client(
                                 DecodedMessage::LrptProgress(_) => AUDIO_MSG_LRPT_PROGRESS,
                                 DecodedMessage::Wefax(_) => AUDIO_MSG_WEFAX_DECODE,
                                 DecodedMessage::WefaxProgress(_) => AUDIO_MSG_WEFAX_PROGRESS,
+                                DecodedMessage::Sstv(_) => AUDIO_MSG_SSTV_DECODE,
+                                DecodedMessage::SstvProgress(_) => AUDIO_MSG_SSTV_PROGRESS,
                             };
                             if let Ok(json) = serde_json::to_vec(&msg) {
                                 if let Err(e) = write_audio_msg(&mut writer_for_rx, msg_type, &json).await {

src/trx-server/src/decoder_history.rs

@@ -11,7 +11,8 @@ use std::time::Instant;
 
 use base64::Engine as _;
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, VdesMessage, WefaxMessage, WsprMessage,
+    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, SstvMessage, VdesMessage, WefaxMessage,
+    WsprMessage,
 };
 
 use crate::history_policy::{
@@ -36,6 +37,7 @@ pub struct DecoderHistories {
     pub wspr: Mutex<VecDeque<(Instant, WsprMessage)>>,
     pub lrpt: Mutex<VecDeque<(Instant, LrptImage)>>,
     pub wefax: Mutex<VecDeque<(Instant, WefaxMessage)>>,
+    pub sstv: Mutex<VecDeque<(Instant, SstvMessage)>>,
     /// Approximate total entry count across all decoders, maintained
     /// atomically so `estimated_total_count()` avoids 11 lock acquisitions.
     total_count: AtomicUsize,
@@ -55,6 +57,7 @@ impl DecoderHistories {
             wspr: Mutex::new(VecDeque::new()),
             lrpt: Mutex::new(VecDeque::new()),
             wefax: Mutex::new(VecDeque::new()),
+            sstv: Mutex::new(VecDeque::new()),
             total_count: AtomicUsize::new(0),
         })
     }
@@ -412,6 +415,42 @@ impl DecoderHistories {
         self.adjust_total_count(before, 0);
     }
 
+    // --- SSTV ---
+
+    fn prune_sstv(history: &mut VecDeque<(Instant, SstvMessage)>) {
+        prune_by_age(history, HISTORY_RETENTION, Instant::now());
+    }
+
+    pub fn record_sstv_message(&self, mut msg: SstvMessage) {
+        if msg.ts_ms.is_none() {
+            msg.ts_ms = Some(current_timestamp_ms());
+        }
+        // The picture is on disk; a megabyte of base64 per entry is not what
+        // the history is for.
+        msg.png_data = None;
+        let mut h = lock_or_recover(&self.sstv, "sstv_history");
+        let before = h.len();
+        h.push_back((Instant::now(), msg));
+        Self::prune_sstv(&mut h);
+        enforce_capacity(&mut h, MAX_HISTORY_ENTRIES);
+        self.adjust_total_count(before, h.len());
+    }
+
+    pub fn snapshot_sstv_history(&self) -> Vec<SstvMessage> {
+        let mut h = lock_or_recover(&self.sstv, "sstv_history");
+        let before = h.len();
+        Self::prune_sstv(&mut h);
+        self.adjust_total_count(before, h.len());
+        h.iter().map(|(_, m)| m.clone()).collect()
+    }
+
+    pub fn clear_sstv_history(&self) {
+        let mut h = lock_or_recover(&self.sstv, "sstv_history");
+        let before = h.len();
+        h.clear();
+        self.adjust_total_count(before, 0);
+    }
+
     // --- WEFAX ---
 
     fn prune_wefax(history: &mut VecDeque<(Instant, WefaxMessage)>) {
@@ -483,7 +522,8 @@ impl DecoderHistories {
             + lock_or_recover(&self.ft2, "ft2_history").len()
             + lock_or_recover(&self.wspr, "wspr_history").len()
             + lock_or_recover(&self.lrpt, "lrpt_history").len()
-            + lock_or_recover(&self.wefax, "wefax_history").len();
+            + lock_or_recover(&self.wefax, "wefax_history").len()
+            + lock_or_recover(&self.sstv, "sstv_history").len();
         self.total_count.store(total, Ordering::Relaxed);
     }
 }

src/trx-server/src/history_store.rs

@@ -19,7 +19,8 @@ use pickledb::{PickleDb, PickleDbDumpPolicy, SerializationMethod};
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
 
 use trx_core::decode::{
-    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, VdesMessage, WefaxMessage, WsprMessage,
+    AisMessage, AprsPacket, CwEvent, Ft8Message, LrptImage, SstvMessage, VdesMessage, WefaxMessage,
+    WsprMessage,
 };
 
 use crate::audio::DecoderHistories;
@@ -158,6 +159,11 @@ pub fn load_all(db: &PickleDb, rig_id: &str, histories: &Arc<DecoderHistories>)
             h.push_back(e);
         }
     }
+    if let Ok(mut h) = histories.sstv.lock() {
+        for e in load_key::<SstvMessage>(db, &k("sstv")) {
+            h.push_back(e);
+        }
+    }
     histories.recalculate_total_count();
 }
 
@@ -223,6 +229,11 @@ pub fn flush_all(db: &mut PickleDb, rig_id: &str, histories: &Arc<DecoderHistori
         drop(h);
         save_key(db, &k("wefax"), &snapshot);
     }
+    if let Ok(h) = histories.sstv.lock() {
+        let snapshot = h.clone();
+        drop(h);
+        save_key(db, &k("sstv"), &snapshot);
+    }
     let _ = db.dump();
 }
 

src/trx-server/src/listener.rs

@@ -494,6 +494,58 @@ where
             }
         };
 
+        // SubscribeSpectrum: turns this connection into a one-way spectrum
+        // stream.  Polling GetSpectrum costs a round trip per frame, so a
+        // client on a slow link could never reach the frame rate it asked for;
+        // pushing decouples the rate from the latency.
+        if matches!(envelope.cmd, ClientCommand::SubscribeSpectrum) {
+            let mut spectrum_rx = handle.spectrum_tx.subscribe();
+            let io_timeout = timeouts.io_timeout;
+            info!(
+                "Client {} subscribed to spectrum stream for rig '{}'",
+                addr, target_rig_id
+            );
+            loop {
+                tokio::select! {
+                    frame = spectrum_rx.recv() => {
+                        match frame {
+                            Ok(frame) => {
+                                let Ok(mut line) = serde_json::to_string(&frame) else { continue };
+                                line.push('\n');
+                                let write = time::timeout(
+                                    io_timeout,
+                                    writer.write_all(line.as_bytes()),
+                                ).await;
+                                match write {
+                                    Ok(Ok(())) => {}
+                                    Ok(Err(e)) => {
+                                        info!("Client {} spectrum write failed: {}", addr, e);
+                                        break;
+                                    }
+                                    Err(_) => {
+                                        info!("Client {} spectrum write timed out", addr);
+                                        break;
+                                    }
+                                }
+                            }
+                            // A client that cannot keep up skips to the newest
+                            // frame; stale spectrum is not worth drawing.
+                            Err(tokio::sync::broadcast::error::RecvError::Lagged(_)) => continue,
+                            Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
+                        }
+                    }
+                    changed = shutdown_rx.changed() => {
+                        match changed {
+                            Ok(()) if *shutdown_rx.borrow() => break,
+                            Ok(()) => {}
+                            Err(_) => break,
+                        }
+                    }
+                }
+            }
+            break;
+        }
+
         // SubscribeMeter: turns this connection into a one-way meter stream.
         // No regular responses are produced; the connection lives until the
         // client disconnects or shutdown fires.
@@ -732,6 +784,7 @@ mod tests {
         let (state_tx, state_rx) = watch::channel(state);
         let _state_tx = state_tx;
         let (meter_tx, _) = tokio::sync::broadcast::channel(8);
+        let (spectrum_tx, _) = tokio::sync::broadcast::channel(4);
         let handle = RigHandle {
             rig_id: "default".to_string(),
             display_name: "Default Rig".to_string(),
@@ -739,6 +792,7 @@ mod tests {
             state_rx,
             audio_port: 4531,
             meter_tx,
+            spectrum_tx,
         };
         let mut map = HashMap::new();
         map.insert("default".to_string(), handle);
@@ -933,6 +987,7 @@ mod tests {
             state_rx: state_rx_a,
             audio_port: 4531,
             meter_tx: meter_tx_a,
+            spectrum_tx: tokio::sync::broadcast::channel(4).0,
         };
 
         let (tx_b, rx_b) = mpsc::channel::<RigRequest>(8);
@@ -945,6 +1000,7 @@ mod tests {
             state_rx: state_rx_b,
             audio_port: 4532,
             meter_tx: meter_tx_b,
+            spectrum_tx: tokio::sync::broadcast::channel(4).0,
         };
 
         let mut map = HashMap::new();
@@ -953,6 +1009,67 @@ mod tests {
         (Arc::new(map), "rig_hf".to_string(), rx_a, rx_b)
     }
 
+    /// Polling spectrum costs a round trip per frame, so the rate a client can
+    /// reach is capped by latency rather than by what it asked for.  Subscribed
+    /// clients get frames pushed instead; this is that path end to end.
+    #[tokio::test]
+    async fn subscribe_spectrum_pushes_frames() {
+        use trx_core::rig::state::SpectrumData;
+
+        let (rigs, default_id) = make_rigs(sample_state());
+        let spectrum_tx = rigs.get("default").expect("rig").spectrum_tx.clone();
+        let ctx = make_ctx(rigs, default_id, HashSet::new());
+        let (mut reader, mut writer, handle, shutdown_tx) = spawn_client_io(ctx);
+
+        writer
+            .write_all(br#"{"cmd":"subscribe_spectrum"}"#)
+            .await
+            .expect("write");
+        writer.write_all(b"\n").await.expect("newline");
+        writer.flush().await.expect("flush");
+
+        // The subscription is registered asynchronously; publish until it takes.
+        let frame = trx_protocol::SpectrumFrame {
+            rig_id: "default".to_string(),
+            spectrum: SpectrumData {
+                bins: vec![-73.4, -20.6, 0.0],
+                center_hz: 14_200_000,
+                sample_rate: 1_920_000,
+                rds: None,
+            },
+            vchan_rds: None,
+        };
+        let mut line = String::new();
+        for _ in 0..50 {
+            let _ = spectrum_tx.send(frame.clone());
+            tokio::select! {
+                read = reader.read_line(&mut line) => {
+                    if read.expect("read") > 0 && !line.trim().is_empty() {
+                        break;
+                    }
+                    line.clear();
+                }
+                _ = tokio::time::sleep(Duration::from_millis(20)) => {}
+            }
+        }
+
+        let received: trx_protocol::SpectrumFrame =
+            serde_json::from_str(line.trim()).unwrap_or_else(|e| panic!("frame {line:?}: {e}"));
+        assert_eq!(received.rig_id, "default");
+        assert_eq!(received.spectrum.center_hz, 14_200_000);
+        // Bins survive the trip quantized to whole dBFS, which is the
+        // resolution the display draws at anyway.
+        assert_eq!(received.spectrum.bins, vec![-73.0, -21.0, 0.0]);
+        // And they travel as base64 rather than a JSON array of floats.
+        assert!(
+            !line.contains("-73"),
+            "bins should not be spelled out on the wire: {line}"
+        );
+
+        let _ = shutdown_tx.send(true);
+        let _ = handle.await;
+    }
+
     #[tokio::test]
     async fn multi_rig_state_isolation() {
         let state_hf = sample_state_custom("HF-Dummy", 14_200_000, trx_core::RigMode::USB);

src/trx-server/src/main.rs

@@ -30,6 +30,8 @@ use trx_core::audio::AudioStreamInfo;
 
 use trx_app::{init_logging, normalize_name};
 use trx_backend::{register_builtin_backends_on, RegistrationContext, RigAccess};
+use trx_config::shared::BoundSocket;
+use trx_config::ConfigFile;
 use trx_core::rig::controller::{AdaptivePolling, ExponentialBackoff};
 use trx_core::rig::request::RigRequest;
 use trx_core::rig::state::RigState;
@@ -56,6 +58,12 @@ struct Cli {
     /// Print example configuration and exit
     #[arg(long = "print-config")]
     print_config: bool,
+    /// Treat unknown configuration keys as a fatal error
+    #[arg(long = "strict-config")]
+    strict_config: bool,
+    /// Validate the configuration and exit without starting anything
+    #[arg(long = "check-config")]
+    check_config: bool,
     /// Rig backend to use (e.g. ft817, ft450d)
     #[arg(short = 'r', long = "rig")]
     rig: Option<String>,
@@ -352,6 +360,7 @@ fn build_sdr_rig_from_instance(rig_cfg: &RigInstanceConfig) -> SdrRigBuildResult
         max_virtual_channels: rig_cfg.sdr.max_virtual_channels,
         nb_enabled: rig_cfg.sdr.noise_blanker.enabled,
         nb_threshold: rig_cfg.sdr.noise_blanker.threshold,
+        spectrum_fft_size: rig_cfg.sdr.spectrum_fft_size,
     })?;
 
     let pcm_rx = sdr_rig.subscribe_pcm();
@@ -452,6 +461,7 @@ fn build_rig_task_config(
         prebuilt_rig: None,
         command_exec_timeout: Duration::from_millis(timeouts.command_exec_timeout_ms),
         poll_refresh_timeout: Duration::from_millis(timeouts.poll_refresh_timeout_ms),
+        spectrum_interval_ms: rig_cfg.sdr.spectrum_interval_ms,
     }
 }
 
@@ -653,38 +663,44 @@ fn spawn_rig_audio_stack(
         }
 
         // Spawn APRS decoder task
-        let aprs_pcm_rx = pcm_tx.subscribe();
-        let aprs_state_rx = state_rx.clone();
-        let aprs_decode_tx = decode_tx.clone();
-        let aprs_sr = rig_cfg.audio.sample_rate;
-        let aprs_ch = rig_cfg.audio.channels;
-        let aprs_shutdown_rx = shutdown_rx.clone();
-        let aprs_logs = decoder_logs.clone();
-        let aprs_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_aprs_decoder(aprs_sr, aprs_ch as u16, aprs_pcm_rx, aprs_state_rx, aprs_decode_tx, aprs_logs, aprs_histories) => {}
-                _ = wait_for_shutdown(aprs_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("aprs") {
+            let aprs_pcm_rx = pcm_tx.subscribe();
+            let aprs_state_rx = state_rx.clone();
+            let aprs_decode_tx = decode_tx.clone();
+            let aprs_sr = rig_cfg.audio.sample_rate;
+            let aprs_ch = rig_cfg.audio.channels;
+            let aprs_shutdown_rx = shutdown_rx.clone();
+            let aprs_logs = decoder_logs.clone();
+            let aprs_histories = histories.clone();
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_aprs_decoder(aprs_sr, aprs_ch as u16, aprs_pcm_rx, aprs_state_rx, aprs_decode_tx, aprs_logs, aprs_histories) => {}
+                    _ = wait_for_shutdown(aprs_shutdown_rx) => {}
+                }
+            }));
+        }
 
         // Spawn HF APRS decoder task
-        let hf_aprs_pcm_rx = pcm_tx.subscribe();
-        let hf_aprs_state_rx = state_rx.clone();
-        let hf_aprs_decode_tx = decode_tx.clone();
-        let hf_aprs_sr = rig_cfg.audio.sample_rate;
-        let hf_aprs_ch = rig_cfg.audio.channels;
-        let hf_aprs_shutdown_rx = shutdown_rx.clone();
-        let hf_aprs_logs = decoder_logs.clone();
-        let hf_aprs_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_hf_aprs_decoder(hf_aprs_sr, hf_aprs_ch as u16, hf_aprs_pcm_rx, hf_aprs_state_rx, hf_aprs_decode_tx, hf_aprs_logs, hf_aprs_histories) => {}
-                _ = wait_for_shutdown(hf_aprs_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("aprs_hf") {
+            let hf_aprs_pcm_rx = pcm_tx.subscribe();
+            let hf_aprs_state_rx = state_rx.clone();
+            let hf_aprs_decode_tx = decode_tx.clone();
+            let hf_aprs_sr = rig_cfg.audio.sample_rate;
+            let hf_aprs_ch = rig_cfg.audio.channels;
+            let hf_aprs_shutdown_rx = shutdown_rx.clone();
+            let hf_aprs_logs = decoder_logs.clone();
+            let hf_aprs_histories = histories.clone();
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_hf_aprs_decoder(hf_aprs_sr, hf_aprs_ch as u16, hf_aprs_pcm_rx, hf_aprs_state_rx, hf_aprs_decode_tx, hf_aprs_logs, hf_aprs_histories) => {}
+                    _ = wait_for_shutdown(hf_aprs_shutdown_rx) => {}
+                }
+            }));
+        }
 
-        if let Some((ais_a_pcm_rx, ais_b_pcm_rx)) = sdr_ais_pcm_rx {
+        if let Some((ais_a_pcm_rx, ais_b_pcm_rx)) =
+            sdr_ais_pcm_rx.filter(|_| rig_cfg.decoders.is_enabled("ais"))
+        {
             let ais_state_rx = state_rx.clone();
             let ais_decode_tx = decode_tx.clone();
             let ais_shutdown_rx = shutdown_rx.clone();
@@ -699,7 +715,7 @@ fn spawn_rig_audio_stack(
             }));
         }
 
-        if let Some(vdes_iq_rx) = sdr_vdes_iq_rx {
+        if let Some(vdes_iq_rx) = sdr_vdes_iq_rx.filter(|_| rig_cfg.decoders.is_enabled("vdes")) {
             let vdes_state_rx = state_rx.clone();
             let vdes_decode_tx = decode_tx.clone();
             let vdes_shutdown_rx = shutdown_rx.clone();
@@ -721,55 +737,61 @@ fn spawn_rig_audio_stack(
         }
 
         // Spawn CW decoder task
-        let cw_pcm_rx = pcm_tx.subscribe();
-        let cw_state_rx = state_rx.clone();
-        let cw_decode_tx = decode_tx.clone();
-        let cw_sr = rig_cfg.audio.sample_rate;
-        let cw_ch = rig_cfg.audio.channels;
-        let cw_shutdown_rx = shutdown_rx.clone();
-        let cw_logs = decoder_logs.clone();
-        let cw_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_cw_decoder(cw_sr, cw_ch as u16, cw_pcm_rx, cw_state_rx, cw_decode_tx, cw_logs, cw_histories) => {}
-                _ = wait_for_shutdown(cw_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("cw") {
+            let cw_pcm_rx = pcm_tx.subscribe();
+            let cw_state_rx = state_rx.clone();
+            let cw_decode_tx = decode_tx.clone();
+            let cw_sr = rig_cfg.audio.sample_rate;
+            let cw_ch = rig_cfg.audio.channels;
+            let cw_shutdown_rx = shutdown_rx.clone();
+            let cw_logs = decoder_logs.clone();
+            let cw_histories = histories.clone();
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_cw_decoder(cw_sr, cw_ch as u16, cw_pcm_rx, cw_state_rx, cw_decode_tx, cw_logs, cw_histories) => {}
+                    _ = wait_for_shutdown(cw_shutdown_rx) => {}
+                }
+            }));
+        }
 
         // Spawn FT8 decoder task
-        let ft8_pcm_rx = pcm_tx.subscribe();
-        let ft8_state_rx = state_rx.clone();
-        let ft8_decode_tx = decode_tx.clone();
-        let ft8_sr = rig_cfg.audio.sample_rate;
-        let ft8_ch = rig_cfg.audio.channels;
-        let ft8_shutdown_rx = shutdown_rx.clone();
-        let ft8_logs = decoder_logs.clone();
-        let ft8_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_ft8_decoder(ft8_sr, ft8_ch as u16, ft8_pcm_rx, ft8_state_rx, ft8_decode_tx, ft8_logs, ft8_histories) => {}
-                _ = wait_for_shutdown(ft8_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("ft8") {
+            let ft8_pcm_rx = pcm_tx.subscribe();
+            let ft8_state_rx = state_rx.clone();
+            let ft8_decode_tx = decode_tx.clone();
+            let ft8_sr = rig_cfg.audio.sample_rate;
+            let ft8_ch = rig_cfg.audio.channels;
+            let ft8_shutdown_rx = shutdown_rx.clone();
+            let ft8_logs = decoder_logs.clone();
+            let ft8_histories = histories.clone();
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_ft8_decoder(ft8_sr, ft8_ch as u16, ft8_pcm_rx, ft8_state_rx, ft8_decode_tx, ft8_logs, ft8_histories) => {}
+                    _ = wait_for_shutdown(ft8_shutdown_rx) => {}
+                }
+            }));
+        }
 
         // Spawn FT4 decoder task
-        let ft4_pcm_rx = pcm_tx.subscribe();
-        let ft4_state_rx = state_rx.clone();
-        let ft4_decode_tx = decode_tx.clone();
-        let ft4_sr = rig_cfg.audio.sample_rate;
-        let ft4_ch = rig_cfg.audio.channels;
-        let ft4_shutdown_rx = shutdown_rx.clone();
-        let ft4_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_ft4_decoder(ft4_sr, ft4_ch as u16, ft4_pcm_rx, ft4_state_rx, ft4_decode_tx, ft4_histories) => {}
-                _ = wait_for_shutdown(ft4_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("ft4") {
+            let ft4_pcm_rx = pcm_tx.subscribe();
+            let ft4_state_rx = state_rx.clone();
+            let ft4_decode_tx = decode_tx.clone();
+            let ft4_sr = rig_cfg.audio.sample_rate;
+            let ft4_ch = rig_cfg.audio.channels;
+            let ft4_shutdown_rx = shutdown_rx.clone();
+            let ft4_histories = histories.clone();
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_ft4_decoder(ft4_sr, ft4_ch as u16, ft4_pcm_rx, ft4_state_rx, ft4_decode_tx, ft4_histories) => {}
+                    _ = wait_for_shutdown(ft4_shutdown_rx) => {}
+                }
+            }));
+        }
 
         // Spawn FT2 decoder task
         #[cfg(feature = "ft2")]
-        {
+        if rig_cfg.decoders.is_enabled("ft2") {
             let ft2_pcm_rx = pcm_tx.subscribe();
             let ft2_state_rx = state_rx.clone();
             let ft2_decode_tx = decode_tx.clone();
@@ -786,54 +808,76 @@ fn spawn_rig_audio_stack(
         }
 
         // Spawn WSPR decoder task
-        let wspr_pcm_rx = pcm_tx.subscribe();
-        let wspr_state_rx = state_rx.clone();
-        let wspr_decode_tx = decode_tx.clone();
-        let wspr_sr = rig_cfg.audio.sample_rate;
-        let wspr_ch = rig_cfg.audio.channels;
-        let wspr_shutdown_rx = shutdown_rx.clone();
-        let wspr_logs = decoder_logs.clone();
-        let wspr_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_wspr_decoder(wspr_sr, wspr_ch as u16, wspr_pcm_rx, wspr_state_rx, wspr_decode_tx, wspr_logs, wspr_histories) => {}
-                _ = wait_for_shutdown(wspr_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("wspr") {
+            let wspr_pcm_rx = pcm_tx.subscribe();
+            let wspr_state_rx = state_rx.clone();
+            let wspr_decode_tx = decode_tx.clone();
+            let wspr_sr = rig_cfg.audio.sample_rate;
+            let wspr_ch = rig_cfg.audio.channels;
+            let wspr_shutdown_rx = shutdown_rx.clone();
+            let wspr_logs = decoder_logs.clone();
+            let wspr_histories = histories.clone();
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_wspr_decoder(wspr_sr, wspr_ch as u16, wspr_pcm_rx, wspr_state_rx, wspr_decode_tx, wspr_logs, wspr_histories) => {}
+                    _ = wait_for_shutdown(wspr_shutdown_rx) => {}
+                }
+            }));
+        }
 
         // Spawn Meteor-M LRPT decoder task
-        let lrpt_pcm_rx = pcm_tx.subscribe();
-        let lrpt_state_rx = state_rx.clone();
-        let lrpt_decode_tx = decode_tx.clone();
-        let lrpt_sr = rig_cfg.audio.sample_rate;
-        let lrpt_ch = rig_cfg.audio.channels;
-        let lrpt_shutdown_rx = shutdown_rx.clone();
-        let lrpt_histories = histories.clone();
-        let lrpt_output_dir = dirs::cache_dir()
-            .unwrap_or_else(|| std::path::PathBuf::from(".cache"))
-            .join("trx-rs")
-            .join("lrpt");
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_lrpt_decoder(lrpt_sr, lrpt_ch as u16, lrpt_pcm_rx, lrpt_state_rx, lrpt_decode_tx, lrpt_histories, lrpt_output_dir) => {}
-                _ = wait_for_shutdown(lrpt_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("lrpt") {
+            let lrpt_pcm_rx = pcm_tx.subscribe();
+            let lrpt_state_rx = state_rx.clone();
+            let lrpt_decode_tx = decode_tx.clone();
+            let lrpt_sr = rig_cfg.audio.sample_rate;
+            let lrpt_ch = rig_cfg.audio.channels;
+            let lrpt_shutdown_rx = shutdown_rx.clone();
+            let lrpt_histories = histories.clone();
+            let lrpt_output_dir = rig_cfg.decoders.output_dir_for("lrpt");
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_lrpt_decoder(lrpt_sr, lrpt_ch as u16, lrpt_pcm_rx, lrpt_state_rx, lrpt_decode_tx, lrpt_histories, lrpt_output_dir) => {}
+                    _ = wait_for_shutdown(lrpt_shutdown_rx) => {}
+                }
+            }));
+        }
 
         // Spawn WEFAX decoder task
-        let wefax_pcm_rx = pcm_tx.subscribe();
-        let wefax_state_rx = state_rx.clone();
-        let wefax_decode_tx = decode_tx.clone();
-        let wefax_sr = rig_cfg.audio.sample_rate;
-        let wefax_ch = rig_cfg.audio.channels;
-        let wefax_shutdown_rx = shutdown_rx.clone();
-        let wefax_histories = histories.clone();
-        handles.push(tokio::spawn(async move {
-            tokio::select! {
-                _ = audio::run_wefax_decoder(wefax_sr, wefax_ch as u16, wefax_pcm_rx, wefax_state_rx, wefax_decode_tx, wefax_histories) => {}
-                _ = wait_for_shutdown(wefax_shutdown_rx) => {}
-            }
-        }));
+        if rig_cfg.decoders.is_enabled("wefax") {
+            let wefax_pcm_rx = pcm_tx.subscribe();
+            let wefax_state_rx = state_rx.clone();
+            let wefax_decode_tx = decode_tx.clone();
+            let wefax_sr = rig_cfg.audio.sample_rate;
+            let wefax_ch = rig_cfg.audio.channels;
+            let wefax_shutdown_rx = shutdown_rx.clone();
+            let wefax_histories = histories.clone();
+            let wefax_output_dir = rig_cfg.decoders.output_dir_for("wefax");
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_wefax_decoder(wefax_sr, wefax_ch as u16, wefax_pcm_rx, wefax_state_rx, wefax_decode_tx, wefax_histories, wefax_output_dir) => {}
+                    _ = wait_for_shutdown(wefax_shutdown_rx) => {}
+                }
+            }));
+        }
+
+        // Spawn SSTV decoder task
+        if rig_cfg.decoders.is_enabled("sstv") {
+            let sstv_pcm_rx = pcm_tx.subscribe();
+            let sstv_state_rx = state_rx.clone();
+            let sstv_decode_tx = decode_tx.clone();
+            let sstv_sr = rig_cfg.audio.sample_rate;
+            let sstv_ch = rig_cfg.audio.channels;
+            let sstv_shutdown_rx = shutdown_rx.clone();
+            let sstv_histories = histories.clone();
+            let sstv_output_dir = rig_cfg.decoders.output_dir_for("sstv");
+            handles.push(tokio::spawn(async move {
+                tokio::select! {
+                    _ = audio::run_sstv_decoder(sstv_sr, sstv_ch as u16, sstv_pcm_rx, sstv_state_rx, sstv_decode_tx, sstv_histories, sstv_output_dir) => {}
+                    _ = wait_for_shutdown(sstv_shutdown_rx) => {}
+                }
+            }));
+        }
     }
 
     if rig_cfg.audio.tx_enabled {
@@ -863,6 +907,82 @@ fn spawn_rig_audio_stack(
     handles
 }
 
+/// Sockets this process will bind, given the config and the CLI overrides.
+///
+/// `--listen` overrides the bind address of both the control listener and every
+/// rig's audio listener, so the two callers of this must agree on the rules.
+fn bound_sockets(cli: &Cli, cfg: &ServerConfig, rigs: &[RigInstanceConfig]) -> Vec<BoundSocket> {
+    let mut sockets = Vec::new();
+    if cfg.listen.enabled {
+        sockets.push(BoundSocket::new(
+            cli.listen.unwrap_or(cfg.listen.listen),
+            cli.port.unwrap_or(cfg.listen.port),
+            "[listen]",
+        ));
+    }
+    let audio_ip = cli.listen.unwrap_or(cfg.audio.listen);
+    for rig in rigs {
+        if rig.audio.enabled {
+            sockets.push(BoundSocket::new(
+                audio_ip,
+                rig.audio.port,
+                format!("rig \"{}\" [audio]", rig.id),
+            ));
+        }
+    }
+    sockets
+}
+
+/// `--check-config`: report everything wrong with the configuration and exit.
+///
+/// Unlike startup, this reports every problem it finds rather than stopping at
+/// the first, so a config can be fixed in one pass.
+fn check_config(cli: &Cli, loaded: &trx_config::ConfigLoad<ServerConfig>) -> DynResult<()> {
+    match &loaded.path {
+        Some(path) => println!("{}", path.display()),
+        None => println!("(no config file found; checking built-in defaults)"),
+    }
+
+    let mut warnings: Vec<String> = loaded.unknown_keys.iter().map(|k| k.to_string()).collect();
+    warnings.extend(ServerConfig::deprecations(&loaded.present_keys));
+    for warning in &warnings {
+        println!("  warning: {}", warning);
+    }
+
+    let mut cfg = loaded.config.clone();
+    let mut errors = Vec::new();
+    if let Err(e) = cfg.resolve_secrets(loaded.path.as_deref()) {
+        errors.push(e);
+    }
+    let cfg = &cfg;
+    let rigs = cfg.resolved_rigs();
+
+    errors.extend(cfg.validate_all());
+    errors.extend(cfg.validate_sdr());
+    errors.extend(cfg.validate_resolved_all(&rigs, &bound_sockets(cli, cfg, &rigs)));
+
+    for e in &errors {
+        println!("  error: {}", e);
+    }
+
+    if errors.is_empty() {
+        println!(
+            "  OK: {} rig(s) configured: {}",
+            rigs.len(),
+            rigs.iter()
+                .map(|r| r.id.as_str())
+                .collect::<Vec<_>>()
+                .join(", ")
+        );
+        if !warnings.is_empty() {
+            println!("  {} warning(s)", warnings.len());
+        }
+        Ok(())
+    } else {
+        Err(format!("{} error(s), {} warning(s)", errors.len(), warnings.len()).into())
+    }
+}
+
 #[tokio::main]
 async fn main() -> DynResult<()> {
     let mut bootstrap_ctx = RegistrationContext::new();
@@ -875,12 +995,30 @@ async fn main() -> DynResult<()> {
         return Ok(());
     }
 
-    let (cfg, config_path) = if let Some(ref path) = cli.config {
-        let cfg = ServerConfig::load_from_file(path)?;
-        (cfg, Some(path.clone()))
+    let loaded = if let Some(ref path) = cli.config {
+        ServerConfig::load_from_file(path)?
     } else {
         ServerConfig::load_from_default_paths()?
     };
+    let config_path = loaded.path.clone();
+
+    if cli.check_config {
+        return check_config(&cli, &loaded);
+    }
+
+    // Logging comes up before any config complaint so the warnings are visible.
+    init_logging(loaded.config.general.log_level.as_deref());
+
+    if let Some(ref path) = config_path {
+        info!("Loaded configuration from {}", path.display());
+    }
+    loaded.report_unknown_keys(cli.strict_config)?;
+    loaded.report_deprecations();
+
+    let mut cfg = loaded.config;
+    // Secrets configured as *_file are read before validation, so everything
+    // downstream sees resolved values.
+    cfg.resolve_secrets(config_path.as_deref())?;
     cfg.validate()
         .map_err(|e| format!("Invalid server configuration: {}", e))?;
 
@@ -893,12 +1031,6 @@ async fn main() -> DynResult<()> {
         std::process::exit(1);
     }
 
-    init_logging(cfg.general.log_level.as_deref());
-
-    if let Some(ref path) = config_path {
-        info!("Loaded configuration from {}", path.display());
-    }
-
     let registry = Arc::new(bootstrap_ctx);
 
     // --- Resolve the effective rig list ---
@@ -960,6 +1092,12 @@ async fn main() -> DynResult<()> {
         (callsign, cfg.general.latitude, cfg.general.longitude)
     };
 
+    // Second validation phase: now that CLI overrides have been folded in, check
+    // the things that need the final rig list — chiefly that no two listeners
+    // claim the same socket.
+    cfg.validate_resolved(&resolved_rigs, &bound_sockets(&cli, &cfg, &resolved_rigs))
+        .map_err(|e| format!("Invalid server configuration: {}", e))?;
+
     info!(
         "Starting trx-server with {} rig(s): {}",
         resolved_rigs.len(),
@@ -1079,6 +1217,9 @@ async fn main() -> DynResult<()> {
         let (state_tx, state_rx) = watch::channel(initial_state);
         let (meter_tx, _) =
             broadcast::channel::<trx_protocol::MeterUpdate>(rig_handle::METER_BROADCAST_CAPACITY);
+        let (spectrum_tx, _) = broadcast::channel::<trx_protocol::SpectrumFrame>(
+            rig_handle::SPECTRUM_BROADCAST_CAPACITY,
+        );
 
         let mut task_config = build_rig_task_config(
             rig_cfg,
@@ -1106,12 +1247,14 @@ async fn main() -> DynResult<()> {
         let rig_shutdown_rx = shutdown_rx.clone();
         let rig_id_supervisor = rig_cfg.id.clone();
         let meter_tx_task = meter_tx.clone();
+        let spectrum_tx_task = spectrum_tx.clone();
         task_handles.push(tokio::spawn(async move {
             let result = rig_task::run_rig_task(
                 task_config,
                 rig_rx,
                 state_tx.clone(),
                 meter_tx_task,
+                spectrum_tx_task,
                 rig_shutdown_rx,
             )
             .await;
@@ -1158,6 +1301,7 @@ async fn main() -> DynResult<()> {
         rig_handles.insert(
             rig_cfg.id.clone(),
             RigHandle {
+                spectrum_tx: spectrum_tx.clone(),
                 rig_id: rig_cfg.id.clone(),
                 display_name: rig_cfg.display_name().to_string(),
                 rig_tx,

src/trx-server/src/rig_handle.rs

@@ -8,13 +8,18 @@ use tokio::sync::{broadcast, mpsc, watch};
 
 use trx_core::rig::request::RigRequest;
 use trx_core::rig::state::RigState;
-use trx_protocol::MeterUpdate;
+use trx_protocol::{MeterUpdate, SpectrumFrame};
 
 /// Bounded broadcast capacity for the meter stream.  Keeps ~0.5 s of buffered
 /// samples at 30 Hz — more than enough slack to tolerate a scheduling blip
 /// without forcing the producer to block or drop silently.
 pub const METER_BROADCAST_CAPACITY: usize = 16;
 
+/// Bounded broadcast capacity for the spectrum stream.  Frames are large and
+/// only the newest one is worth drawing, so the buffer stays shallow: a slow
+/// client lags and skips rather than making the server hold stale frames.
+pub const SPECTRUM_BROADCAST_CAPACITY: usize = 4;
+
 /// A handle to a single running rig backend.
 ///
 /// One `RigHandle` is created per rig in `main.rs` and stored in the shared
@@ -34,4 +39,8 @@ pub struct RigHandle {
     /// ~6–7 Hz (CAT).  Consumed by `SubscribeMeter` clients; independent of
     /// the slower `state_rx` snapshot path.
     pub meter_tx: broadcast::Sender<MeterUpdate>,
+    /// Per-rig spectrum frames published by `rig_task` while at least one
+    /// client is subscribed.  Consumed by `SubscribeSpectrum` clients; the
+    /// producer skips the work entirely when nobody is listening.
+    pub spectrum_tx: broadcast::Sender<SpectrumFrame>,
 }

src/trx-server/src/rig_task.rs

@@ -23,7 +23,7 @@ use trx_core::rig::request::RigRequest;
 use trx_core::rig::state::{RigMode, RigSnapshot, RigState};
 use trx_core::rig::{RigCat, RigRxStatus, RigTxStatus};
 use trx_core::{DynResult, RigError, RigResult};
-use trx_protocol::MeterUpdate;
+use trx_protocol::{MeterUpdate, SpectrumFrame};
 
 use crate::audio::DecoderHistories;
 use crate::error::is_invalid_bcd_error;
@@ -64,6 +64,8 @@ pub struct RigTaskConfig {
     pub command_exec_timeout: Duration,
     /// Maximum time for a CAT poll refresh cycle.
     pub poll_refresh_timeout: Duration,
+    /// How often to push a spectrum frame to subscribed clients, in ms.
+    pub spectrum_interval_ms: u64,
 }
 
 impl Default for RigTaskConfig {
@@ -94,6 +96,7 @@ impl Default for RigTaskConfig {
             prebuilt_rig: None,
             command_exec_timeout: DEFAULT_COMMAND_EXEC_TIMEOUT,
             poll_refresh_timeout: DEFAULT_POLL_REFRESH_TIMEOUT,
+            spectrum_interval_ms: 50,
         }
     }
 }
@@ -115,6 +118,7 @@ pub async fn run_rig_task(
     mut rx: mpsc::Receiver<RigRequest>,
     state_tx: watch::Sender<RigState>,
     meter_tx: broadcast::Sender<MeterUpdate>,
+    spectrum_tx: broadcast::Sender<SpectrumFrame>,
     mut shutdown_rx: watch::Receiver<bool>,
 ) -> DynResult<()> {
     let histories = config.histories.clone();
@@ -273,6 +277,13 @@ pub async fn run_rig_task(
     } else {
         Duration::from_millis(150)
     };
+    // Spectrum frames get their own tick so a subscribed client never pays a
+    // round trip per frame.  The FFT is computed by the SDR thread either way;
+    // this only reads the latest result, and only while somebody is subscribed.
+    let spectrum_tick_duration = Duration::from_millis(config.spectrum_interval_ms.max(1));
+    let mut spectrum_tick: std::pin::Pin<Box<tokio::time::Sleep>> =
+        Box::pin(tokio::time::sleep(spectrum_tick_duration));
+
     let meter_task_start = Instant::now();
     let meter_state_delta_db: f64 = 0.25;
     let rig_id = config.rig_id.clone();
@@ -302,6 +313,21 @@ pub async fn run_rig_task(
                     Err(_) => break,
                 }
             }
+            // Push the latest spectrum frame to subscribed clients.
+            _ = &mut spectrum_tick => {
+                spectrum_tick = Box::pin(tokio::time::sleep(spectrum_tick_duration));
+                // `send` fails only when nobody is listening, but building the
+                // frame clones a few KB of bins, so check before doing the work.
+                if spectrum_tx.receiver_count() > 0 {
+                    if let Some(spectrum) = rig.as_sdr_ref().and_then(|s| s.get_spectrum()) {
+                        let _ = spectrum_tx.send(SpectrumFrame {
+                            rig_id: rig_id.clone(),
+                            spectrum,
+                            vchan_rds: rig.as_sdr_ref().and_then(|s| s.get_vchan_rds()),
+                        });
+                    }
+                }
+            }
             // Fast meter-only refresh between full polls.
             _ = &mut meter_tick => {
                 meter_tick = Box::pin(tokio::time::sleep(meter_tick_duration));
@@ -657,6 +683,18 @@ async fn process_command(
             let _ = ctx.state_tx.send(ctx.state.clone());
             return snapshot_from(ctx.state);
         }
+        RigCommand::SetSstvDecodeEnabled(en) => {
+            ctx.state.decoders.sstv_decode_enabled = en;
+            info!("SSTV decode {}", if en { "enabled" } else { "disabled" });
+            let _ = ctx.state_tx.send(ctx.state.clone());
+            return snapshot_from(ctx.state);
+        }
+        RigCommand::ResetSstvDecoder => {
+            ctx.histories.clear_sstv_history();
+            ctx.state.reset_seqs.sstv_decode_reset_seq += 1;
+            let _ = ctx.state_tx.send(ctx.state.clone());
+            return snapshot_from(ctx.state);
+        }
         RigCommand::SetBandwidth(hz) => {
             if let Some(sdr) = ctx.rig.as_sdr() {
                 if let Err(e) = sdr.set_bandwidth(hz).await {

src/trx-server/trx-backend/trx-backend-soapysdr/src/dsp.rs

@@ -154,6 +154,7 @@ impl SdrPipeline {
         squelch_cfg: VirtualSquelchConfig,
         nb_cfg: NoiseBlankerConfig,
         channels: &[(f64, RigMode, u32)],
+        spectrum_fft_size: usize,
     ) -> Self {
         const IQ_BROADCAST_CAPACITY: usize = 64;
         let (iq_tx, _iq_rx) = broadcast::channel::<Vec<Complex<f32>>>(IQ_BROADCAST_CAPACITY);
@@ -219,6 +220,7 @@ impl SdrPipeline {
             .name("sdr-iq-read".to_string())
             .spawn(move || {
                 iq_read_loop(
+                    spectrum_fft_size,
                     source,
                     sdr_sample_rate,
                     thread_dsps,
@@ -317,6 +319,7 @@ pub const IQ_BLOCK_SIZE: usize = 4096;
 
 #[allow(clippy::too_many_arguments)]
 fn iq_read_loop(
+    spectrum_fft_size: usize,
     mut source: Box<dyn IqSource>,
     sdr_sample_rate: u32,
     channel_dsps: Arc<RwLock<Vec<Arc<Mutex<ChannelDsp>>>>>,
@@ -335,7 +338,7 @@ fn iq_read_loop(
     };
     let throttle = !source.is_blocking();
 
-    let mut spectrum = SpectrumSnapshotter::new();
+    let mut spectrum = SpectrumSnapshotter::new(spectrum_fft_size);
     let mut read_error_streak: u32 = 0;
     let mut zero_read_streak: u32 = 0;
     let mut overflow_log_window_start: Option<Instant> = None;
@@ -572,6 +575,7 @@ mod tests {
             VirtualSquelchConfig::default(),
             NoiseBlankerConfig::default(),
             &[(200_000.0, RigMode::USB, 3000)],
+            1024,
         );
         assert_eq!(pipeline.pcm_senders.len(), 1);
         assert_eq!(pipeline.channel_dsps.read().unwrap().len(), 1);
@@ -590,6 +594,7 @@ mod tests {
             VirtualSquelchConfig::default(),
             NoiseBlankerConfig::default(),
             &[],
+            1024,
         );
         assert_eq!(pipeline.pcm_senders.len(), 0);
         assert_eq!(pipeline.channel_dsps.read().unwrap().len(), 0);

src/trx-server/trx-backend/trx-backend-soapysdr/src/dsp/spectrum.rs

@@ -9,28 +9,36 @@ use num_complex::Complex;
 use rustfft::num_complex::Complex as FftComplex;
 use rustfft::FftPlanner;
 
-/// Number of FFT bins for the spectrum display.
-pub(super) const SPECTRUM_FFT_SIZE: usize = 1024;
+/// Default number of FFT bins for the spectrum display, used when the config
+/// does not say otherwise.
+pub(super) const DEFAULT_SPECTRUM_FFT_SIZE: usize = 1024;
 
 /// Update the spectrum buffer every this many IQ blocks (~10 Hz at 1.92 MHz / 4096 block).
 pub(super) const SPECTRUM_UPDATE_BLOCKS: usize = 4;
 
 pub(super) struct SpectrumSnapshotter {
+    fft_size: usize,
     hann_window: Vec<f32>,
     fft: std::sync::Arc<dyn rustfft::Fft<f32>>,
     counter: usize,
 }
 
 impl SpectrumSnapshotter {
-    pub(super) fn new() -> Self {
-        let hann_window: Vec<f32> = (0..SPECTRUM_FFT_SIZE)
-            .map(|i| 0.5 * (1.0 - (2.0 * PI * i as f32 / (SPECTRUM_FFT_SIZE - 1) as f32).cos()))
+    pub(super) fn new(fft_size: usize) -> Self {
+        let fft_size = if fft_size >= 2 {
+            fft_size
+        } else {
+            DEFAULT_SPECTRUM_FFT_SIZE
+        };
+        let hann_window: Vec<f32> = (0..fft_size)
+            .map(|i| 0.5 * (1.0 - (2.0 * PI * i as f32 / (fft_size - 1) as f32).cos()))
             .collect();
 
         let mut planner = FftPlanner::<f32>::new();
-        let fft = planner.plan_fft_forward(SPECTRUM_FFT_SIZE);
+        let fft = planner.plan_fft_forward(fft_size);
 
         Self {
+            fft_size,
             hann_window,
             fft,
             counter: 0,
@@ -48,7 +56,7 @@ impl SpectrumSnapshotter {
         }
         self.counter = 0;
 
-        let take = samples.len().min(SPECTRUM_FFT_SIZE);
+        let take = samples.len().min(self.fft_size);
         let mut buf: Vec<FftComplex<f32>> = samples[..take]
             .iter()
             .enumerate()
@@ -59,16 +67,15 @@ impl SpectrumSnapshotter {
                 )
             })
             .collect();
-        buf.resize(SPECTRUM_FFT_SIZE, FftComplex::new(0.0, 0.0));
+        buf.resize(self.fft_size, FftComplex::new(0.0, 0.0));
         self.fft.process(&mut buf);
 
-        let half = SPECTRUM_FFT_SIZE / 2;
+        let half = self.fft_size / 2;
         let bins: Vec<f32> = buf[half..]
             .iter()
             .chain(buf[..half].iter())
             .map(|value| {
-                let mag =
-                    (value.re * value.re + value.im * value.im).sqrt() / SPECTRUM_FFT_SIZE as f32;
+                let mag = (value.re * value.re + value.im * value.im).sqrt() / self.fft_size as f32;
                 20.0 * mag.max(1e-10_f32).log10()
             })
             .collect();

src/trx-server/trx-backend/trx-backend-soapysdr/src/lib.rs

@@ -73,6 +73,11 @@ pub struct SoapySdrConfig {
     pub nb_enabled: bool,
     /// Noise blanker impulse threshold multiplier.
     pub nb_threshold: f64,
+    /// FFT bin count for the spectrum display; a power of two.
+    ///
+    /// Fewer bins cost less DSP and put fewer bytes on the network per frame,
+    /// which is what a slow server↔client link cares about.
+    pub spectrum_fft_size: usize,
 }
 
 impl Default for SoapySdrConfig {
@@ -99,6 +104,7 @@ impl Default for SoapySdrConfig {
             max_virtual_channels: 4,
             nb_enabled: false,
             nb_threshold: 10.0,
+            spectrum_fft_size: 1024,
         }
     }
 }
@@ -194,6 +200,7 @@ impl SoapySdrRig {
         let max_virtual_channels = config.max_virtual_channels;
         let nb_enabled = config.nb_enabled;
         let nb_threshold = config.nb_threshold;
+        let spectrum_fft_size = config.spectrum_fft_size;
         tracing::info!(
             "initialising SoapySDR backend (args={:?}, gain_mode={:?}, gain_db={}, max_gain_db={:?})",
             args,
@@ -293,6 +300,7 @@ impl SoapySdrRig {
                 threshold: nb_threshold as f32,
             },
             &all_channels,
+            spectrum_fft_size,
         ));
 
         let info = RigInfo {
@@ -418,6 +426,7 @@ impl SoapySdrRig {
         nb_threshold: f64,
     ) -> DynResult<Self> {
         Self::new_from_config(SoapySdrConfig {
+            spectrum_fft_size: 1024,
             args: args.to_string(),
             channels: channels.to_vec(),
             gain_mode: gain_mode.to_string(),

src/trx-server/trx-backend/trx-backend-soapysdr/src/vchan_impl.rs

@@ -439,6 +439,7 @@ mod tests {
             VirtualSquelchConfig::default(),
             NoiseBlankerConfig::default(),
             &[(0.0, RigMode::USB, 3_000)],
+            1024,
         ))
     }
 

trx-rs.toml.example

@@ -1,36 +1,60 @@
+# trx-rs example configuration
+#
+# Generated from the config structs; regenerate with:
+#     cargo run -p trx-config --example generate_example
+#
+# Both sections are optional: trx-server reads [trx-server], trx-client reads
+# [trx-client], and either may live in its own file with the section header
+# omitted.  Any string may use ${ENV_VAR}, and credentials may be moved out of
+# this file with the matching *_file keys.
+#
+# Check a config without starting anything:
+#     trx-server --check-config --config trx-rs.toml
+#     trx-client --check-config --config trx-rs.toml
+
+# Server: drives the radio hardware.
 [trx-server]
 rigs = []
 
+# Station identity.  Coordinates feed PSKReporter and the map.
 [trx-server.general]
 callsign = "N0CALL"
 log_level = "info"
 latitude = 52.2297
 longitude = 21.0122
 
+# Single-rig layout.  For several radios, delete this and use [[rigs]].
 [trx-server.rig]
 model = "ft817"
 initial_freq_hz = 144300000
 initial_mode = "USB"
 
+# How to reach the radio: serial, tcp, or sdr.
 [trx-server.rig.access]
 type = "serial"
 port = "/dev/ttyUSB0"
 baud = 9600
 
+# CAT polling and retry behaviour.
 [trx-server.behavior]
 poll_interval_ms = 500
 poll_interval_tx_ms = 100
 max_retries = 3
 retry_base_delay_ms = 100
+vfo_prime = true
 
+# JSON control listener that trx-client connects to.
 [trx-server.listen]
 enabled = true
 listen = "127.0.0.1"
 port = 4530
 
+# Tokens clients must present.  Empty means no authentication.
+# Use tokens_file = "/etc/trx-rs/tokens" to keep them out of this file.
 [trx-server.listen.auth]
 tokens = []
 
+# Opus audio stream for trx-client.
 [trx-server.audio]
 enabled = true
 listen = "127.0.0.1"
@@ -42,25 +66,53 @@ channels = 2
 frame_duration_ms = 20
 bitrate_bps = 256000
 
+# Report FT8/FT4/WSPR spots to pskreporter.info.
 [trx-server.pskreporter]
 enabled = false
 host = "report.pskreporter.info"
 port = 4739
 
+# Forward received APRS frames to APRS-IS.
 [trx-server.aprsfi]
 enabled = false
 host = "rotate.aprs.net"
 port = 14580
 passcode = -1
+beacon = false
+beacon_interval_secs = 1200
+beacon_symbol_table = "/"
+beacon_symbol_code = "-"
 
+# Write decodes to JSON Lines files.
 [trx-server.decode_logs]
 enabled = false
-dir = "/path/to/log/dir"
+dir = "/var/lib/trx-rs/decoders"
 aprs_file = "TRXRS-APRS-%YYYY%-%MM%-%DD%.log"
 cw_file = "TRXRS-CW-%YYYY%-%MM%-%DD%.log"
 ft8_file = "TRXRS-FT8-%YYYY%-%MM%-%DD%.log"
 wspr_file = "TRXRS-WSPR-%YYYY%-%MM%-%DD%.log"
+wefax_file = "TRXRS-WEFAX-%YYYY%-%MM%-%DD%.log"
 
+# Which decoders run.  Trimming this list saves real CPU on small boxes.
+# Valid names: aprs, aprs_hf, ais, cw, ft2, ft4, ft8, lrpt, sstv, vdes, wefax, wspr.
+# output_dir sets where sstv/wefax/lrpt write images (default: user cache dir).
+[trx-server.decoders]
+enabled = [
+    "aprs",
+    "aprs_hf",
+    "ais",
+    "cw",
+    "ft2",
+    "ft4",
+    "ft8",
+    "lrpt",
+    "sstv",
+    "vdes",
+    "wefax",
+    "wspr",
+]
+
+# SoapySDR pipeline; used when [rig.access] type = "sdr".
 [trx-server.sdr]
 sample_rate = 1920000
 bandwidth = 1500000
@@ -68,17 +120,38 @@ wfm_deemphasis_us = 50
 center_offset_hz = 100000
 channels = []
 max_virtual_channels = 4
+spectrum_fft_size = 1024
+spectrum_interval_ms = 50
 
+# "auto" for hardware AGC, or "manual".
 [trx-server.sdr.gain]
 mode = "auto"
 value = 30.0
 
+# Software squelch on demodulated audio.
 [trx-server.sdr.squelch]
 enabled = false
 threshold_db = -65.0
 hysteresis_db = 3.0
 tail_ms = 180
 
+# Impulse-noise suppression on the IQ stream.
+[trx-server.sdr.noise_blanker]
+enabled = false
+threshold = 10.0
+
+# Timeout and buffer tuning.  The defaults suit most setups.
+[trx-server.timeouts]
+command_exec_timeout_ms = 10000
+poll_refresh_timeout_ms = 8000
+io_timeout_ms = 10000
+request_timeout_ms = 12000
+rig_task_channel_buffer = 32
+
+# Client: exposes the radio to users.
+[trx-client]
+
+# Labels shown in the web UI.
 [trx-client.general]
 callsign = "N0CALL"
 website_url = "https://haxx.space"
@@ -86,24 +159,52 @@ website_name = "haxx.space"
 ais_vessel_url_base = "https://www.vesselfinder.com/?mmsi="
 log_level = "info"
 
+# Legacy single-remote form; prefer [[remotes]] below.
 [trx-client.remote]
-url = "192.168.1.100:9000"
-rig_id = "hf"
 poll_interval_ms = 750
+spectrum_interval_ms = 50
 
 [trx-client.remote.auth]
+
+[[trx-client.remotes]]
+name = "home-hf"
+url = "192.168.1.100:4530"
+rig_id = "hf"
+poll_interval_ms = 750
+spectrum_interval_ms = 50
+
+[trx-client.remotes.auth]
 token = "my-token"
 
+[[trx-client.remotes]]
+name = "home-vhf"
+url = "192.168.1.100:4530"
+rig_id = "vhf"
+poll_interval_ms = 750
+spectrum_interval_ms = 50
+
+[trx-client.remotes.auth]
+token = "my-token"
+
+# Web UI.  default_rig_name and the per-rig maps are keyed by the
+# [[remotes]] name, not the server-side rig id.
 [trx-client.frontends.http]
 enabled = true
 listen = "127.0.0.1"
 port = 8080
-default_rig_id = "hf"
+default_rig_name = "home-hf"
 initial_map_zoom = 10
 spectrum_coverage_margin_hz = 50000
 spectrum_usable_span_ratio = 0.9200000166893005
 show_sdr_gain_control = true
+bandplan_enabled = true
+bandplan_region = "iaru_r1"
+decode_history_retention_min = 1440
 
+[trx-client.frontends.http.decode_history_retention_min_by_rig]
+
+# Passphrase login for the web UI.  rx_passphrase_file and
+# control_passphrase_file keep the secrets out of this file.
 [trx-client.frontends.http.auth]
 enabled = false
 rx_passphrase = "rx-passphrase-example"
@@ -113,6 +214,7 @@ session_ttl_min = 480
 cookie_secure = false
 cookie_same_site = "Lax"
 
+# Hamlib-compatible TCP interface, one listener per rig.
 [trx-client.frontends.rigctl]
 enabled = false
 listen = "127.0.0.1"
@@ -120,6 +222,7 @@ port = 4532
 
 [trx-client.frontends.rigctl.rig_ports]
 
+# JSON-over-TCP control interface.
 [trx-client.frontends.http_json]
 enabled = true
 listen = "127.0.0.1"
@@ -128,12 +231,16 @@ port = 0
 [trx-client.frontends.http_json.auth]
 tokens = []
 
+# Where to fetch the audio stream from.
 [trx-client.frontends.audio]
 enabled = true
 server_port = 4531
 
+[trx-client.frontends.audio.rig_urls]
+
 [trx-client.frontends.audio.rig_ports]
 
+# Play RX audio on a local sound device and capture TX from one.
 [trx-client.frontends.audio.bridge]
 enabled = false
 bitrate_bps = 192000