[fix](trx-rs): wire DSP signal strength to Signal strength field and per-vchan SSE

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

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

@@ -296,6 +296,7 @@ pub struct ChannelDsp {
     force_mono_pcm: bool,
     squelch: VirtualSquelch,
     noise_blanker: NoiseBlanker,
+    last_signal_db: f32,
 }
 
 impl ChannelDsp {
@@ -521,6 +522,7 @@ impl ChannelDsp {
             force_mono_pcm,
             squelch: VirtualSquelch::new(squelch_cfg),
             noise_blanker: NoiseBlanker::new(nb_cfg.enabled, nb_cfg.threshold),
+            last_signal_db: -120.0,
         }
     }
 
@@ -615,6 +617,10 @@ impl ChannelDsp {
             .unwrap_or(0)
     }
 
+    pub fn signal_db(&self) -> f32 {
+        self.last_signal_db
+    }
+
     pub fn reset_rds(&mut self) {
         if let Some(decoder) = &mut self.wfm_decoder {
             decoder.reset_rds();
@@ -740,6 +746,7 @@ impl ChannelDsp {
             .sum::<f32>()
             / decimated.len() as f32;
         let signal_db = 10.0 * signal_power.max(1e-12).log10();
+        self.last_signal_db = signal_db;
         const WFM_OUTPUT_GAIN: f32 = 0.50;
         let mut audio = if let Some(decoder) = self.wfm_decoder.as_mut() {
             let mut out = decoder.process_iq(decimated);

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

@@ -550,8 +550,21 @@ impl RigCat for SoapySdrRig {
     fn get_signal_strength<'a>(
         &'a mut self,
     ) -> Pin<Box<dyn std::future::Future<Output = DynResult<u8>> + Send + 'a>> {
-        // RSSI from real device pending SDR hardware wiring; return 0 for now.
-        Box::pin(async move { Ok(0u8) })
+        Box::pin(async move {
+            let signal_db = self
+                .pipeline
+                .channel_dsps
+                .read()
+                .unwrap()
+                .get(self.primary_channel_idx)
+                .and_then(|dsp| dsp.lock().ok().map(|d| d.signal_db()))
+                .unwrap_or(-120.0);
+            // Map DSP signal power (roughly -120 .. 0 dBFS) to 0..15 range
+            // to match the FT-817 meter scale used by map_signal_strength.
+            let clamped = signal_db.clamp(-120.0, 0.0);
+            let raw = ((clamped + 120.0) / 120.0 * 15.0).round() as u8;
+            Ok(raw.min(15))
+        })
     }
 
     // -- TX / unsupported methods -------------------------------------------

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

@@ -245,12 +245,19 @@ impl SdrVirtualChannelManager {
         let dsps = self.pipeline.channel_dsps.read().unwrap();
         channels
             .iter()
-            .filter(|ch| matches!(ch.mode, RigMode::WFM))
             .map(|ch| {
-                let rds = dsps
-                    .get(ch.pipeline_slot)
-                    .and_then(|dsp| dsp.lock().ok().and_then(|d| d.rds_data()));
-                VchanRdsEntry { id: ch.id, rds }
+                let dsp_guard = dsps.get(ch.pipeline_slot).and_then(|dsp| dsp.lock().ok());
+                let rds = if matches!(ch.mode, RigMode::WFM) {
+                    dsp_guard.as_ref().and_then(|d| d.rds_data())
+                } else {
+                    None
+                };
+                let signal_db = dsp_guard.as_ref().map(|d| d.signal_db());
+                VchanRdsEntry {
+                    id: ch.id,
+                    rds,
+                    signal_db,
+                }
             })
             .collect()
     }