diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js
index 4e0c1d72..6f2c2ef5 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js
@@ -390,6 +390,77 @@
     else window.history.pushState({}, "", nextUrl);
   }
 
+  // src/features/radio/auto-bandwidth.ts
+  function clampPercent(value) {
+    const numeric = Number(value) || 0;
+    return Math.max(0, Math.min(100, numeric)) / 100;
+  }
+  function estimateOccupiedBandwidth(data, centerHz, mode, limits, interference = {}) {
+    if (!data || !Array.isArray(data.bins) && !ArrayBuffer.isView(data.bins) || !Number.isFinite(centerHz)) return null;
+    const bins = Array.from(data.bins);
+    if (bins.length < 3) return null;
+    const maxIdx = bins.length - 1;
+    const hzPerBin = data.sample_rate / maxIdx;
+    const fullLoHz = data.center_hz - data.sample_rate / 2;
+    const centerIdx = Math.max(
+      1,
+      Math.min(maxIdx - 1, Math.round((centerHz - fullLoHz) / data.sample_rate * maxIdx))
+    );
+    const normalizedMode = mode.toUpperCase();
+    const [defaultBw, minBw, maxBw, stepBw] = limits;
+    const oneSided = ["USB", "DIG", "CW"].includes(normalizedMode) ? 1 : ["LSB", "CWR"].includes(normalizedMode) ? -1 : 0;
+    const isWfm = normalizedMode === "WFM";
+    const smoothRadius = isWfm ? 3 : 1;
+    const smoothed = bins.map((_, index) => {
+      let sum = 0;
+      let count = 0;
+      for (let adjacent = Math.max(0, index - smoothRadius); adjacent <= Math.min(maxIdx, index + smoothRadius); adjacent += 1) {
+        sum += bins[adjacent] ?? 0;
+        count += 1;
+      }
+      return sum / count;
+    });
+    const sorted = [...bins].sort((left, right) => left - right);
+    const noise = sorted[Math.floor(sorted.length * 0.2)] ?? -Infinity;
+    const maxSpanBins = Math.max(2, Math.ceil(maxBw / hzPerBin));
+    const searchHalfBins = oneSided === 0 ? Math.ceil(maxSpanBins / 2) : maxSpanBins;
+    const searchLo = Math.max(1, centerIdx - (oneSided > 0 ? 2 : searchHalfBins));
+    const searchHi = Math.min(maxIdx - 1, centerIdx + (oneSided < 0 ? 2 : searchHalfBins));
+    let peak = -Infinity;
+    for (let index = searchLo; index <= searchHi; index += 1) {
+      peak = Math.max(peak, smoothed[index] ?? -Infinity);
+    }
+    const snr = peak - noise;
+    if (!Number.isFinite(snr) || snr < (isWfm ? 5 : 4)) return isWfm ? minBw : defaultBw;
+    const threshold = noise + Math.max(3, Math.min(isWfm ? 6 : 10, snr * (isWfm ? 0.18 : 0.28)));
+    const allowedGap = Math.max(isWfm ? 4 : 2, Math.ceil((isWfm ? 12e3 : stepBw) / hzPerBin));
+    const occupiedExtent = (direction, limitBins) => {
+      let lastOccupied = centerIdx;
+      let gap = 0;
+      for (let offset = 0; offset <= limitBins; offset += 1) {
+        const index = centerIdx + direction * offset;
+        if (index <= 0 || index >= maxIdx) break;
+        if ((smoothed[index] ?? -Infinity) >= threshold) {
+          lastOccupied = index;
+          gap = 0;
+        } else if (++gap > allowedGap) break;
+      }
+      return Math.abs(lastOccupied - centerIdx) * hzPerBin;
+    };
+    let rawBw = oneSided !== 0 ? occupiedExtent(oneSided, maxSpanBins) : 2 * Math.max(occupiedExtent(-1, searchHalfBins), occupiedExtent(1, searchHalfBins));
+    rawBw *= isWfm ? 1.08 : 1.12;
+    if (isWfm) {
+      const aci = clampPercent(interference.aci);
+      const cci = clampPercent(interference.cci);
+      const aciCap = maxBw - (maxBw - minBw) * aci;
+      const cciFloor = minBw + (defaultBw - minBw) * 0.65;
+      const cciCap = maxBw - (maxBw - cciFloor) * cci;
+      rawBw = Math.min(rawBw, aciCap, cciCap);
+    }
+    const clamped = Math.max(minBw, Math.min(maxBw, rawBw));
+    return Math.max(stepBw, Math.round(clamped / stepBw) * stepBw);
+  }
+
   // src/app.js
   void loadDecoderRegistry(refreshOperatorLayoutCapabilities);
   var authRole = null;
@@ -4089,84 +4160,18 @@ ${unsupportedBandSummary()}`;
       window.trxUi?.notify("Bandwidth could not be changed", { kind: "error", action: { label: "Retry", run: applyBandwidthFromInput } });
     }
   }
-  function estimateOccupiedBandwidth(data, centerHz, interference = {}) {
-    if (!data || !isBinsArray(data.bins) || data.bins.length < 3 || !Number.isFinite(centerHz)) {
-      return null;
-    }
-    const bins = data.bins;
-    const maxIdx = bins.length - 1;
-    const hzPerBin = data.sample_rate / maxIdx;
-    const fullLoHz = data.center_hz - data.sample_rate / 2;
-    const centerIdx = Math.max(
-      1,
-      Math.min(maxIdx - 1, Math.round((centerHz - fullLoHz) / data.sample_rate * maxIdx))
-    );
-    const mode = (modeEl ? modeEl.value : "USB").toUpperCase();
-    const [defaultBw, minBw, maxBw, stepBw] = mwDefaultsForMode(mode);
-    const oneSided = mode === "USB" || mode === "DIG" || mode === "CW" ? 1 : mode === "LSB" || mode === "CWR" ? -1 : 0;
-    const isWfm = mode === "WFM";
-    const smoothRadius = isWfm ? 3 : 1;
-    const smoothed = bins.map((_, i) => {
-      let sum = 0;
-      let count = 0;
-      for (let j = Math.max(0, i - smoothRadius); j <= Math.min(maxIdx, i + smoothRadius); j++) {
-        sum += bins[j];
-        count += 1;
-      }
-      return sum / count;
-    });
-    const sorted = [...bins].sort((a, b) => a - b);
-    const noise = sorted[Math.floor(sorted.length * 0.2)];
-    const maxSpanBins = Math.max(2, Math.ceil(maxBw / hzPerBin));
-    const searchHalfBins = oneSided === 0 ? Math.ceil(maxSpanBins / 2) : maxSpanBins;
-    const searchLo = Math.max(1, centerIdx - (oneSided > 0 ? 2 : searchHalfBins));
-    const searchHi = Math.min(maxIdx - 1, centerIdx + (oneSided < 0 ? 2 : searchHalfBins));
-    let peak = -Infinity;
-    for (let i = searchLo; i <= searchHi; i++) peak = Math.max(peak, smoothed[i]);
-    const snr = peak - noise;
-    if (!Number.isFinite(snr) || snr < (isWfm ? 5 : 4)) return isWfm ? minBw : defaultBw;
-    const threshold = noise + Math.max(3, Math.min(isWfm ? 6 : 10, snr * (isWfm ? 0.18 : 0.28)));
-    const allowedGap = Math.max(isWfm ? 4 : 2, Math.ceil((isWfm ? 12e3 : stepBw) / hzPerBin));
-    function occupiedExtent(direction, limitBins) {
-      let lastOccupied = centerIdx;
-      let gap = 0;
-      for (let n = 0; n <= limitBins; n++) {
-        const i = centerIdx + direction * n;
-        if (i <= 0 || i >= maxIdx) break;
-        if (smoothed[i] >= threshold) {
-          lastOccupied = i;
-          gap = 0;
-        } else if (++gap > allowedGap) {
-          break;
-        }
-      }
-      return Math.abs(lastOccupied - centerIdx) * hzPerBin;
-    }
-    let rawBw;
-    if (oneSided !== 0) {
-      rawBw = occupiedExtent(oneSided, maxSpanBins);
-    } else {
-      const leftHz = occupiedExtent(-1, searchHalfBins);
-      const rightHz = occupiedExtent(1, searchHalfBins);
-      rawBw = 2 * Math.max(leftHz, rightHz);
-    }
-    rawBw *= isWfm ? 1.08 : 1.12;
-    if (isWfm) {
-      const aci = Math.max(0, Math.min(100, Number(interference.aci) || 0)) / 100;
-      const cci = Math.max(0, Math.min(100, Number(interference.cci) || 0)) / 100;
-      const aciCap = maxBw - (maxBw - minBw) * aci;
-      const cciFloor = minBw + (defaultBw - minBw) * 0.65;
-      const cciCap = maxBw - (maxBw - cciFloor) * cci;
-      rawBw = Math.min(rawBw, aciCap, cciCap);
-    }
-    const clamped = Math.max(minBw, Math.min(maxBw, rawBw));
-    return Math.max(stepBw, Math.round(clamped / stepBw) * stepBw);
-  }
   async function applyAutoBandwidth() {
     if (!lastSpectrumData || lastFreqHz == null) return;
     const onVirtual = window.trx.modules.vchan?.isOnVirtual() === true;
     const interference = onVirtual ? {} : { cci: lastWfmCci, aci: lastWfmAci };
-    const estimated = estimateOccupiedBandwidth(lastSpectrumData, lastFreqHz, interference);
+    const mode = (modeEl?.value || "").toUpperCase();
+    const estimated = estimateOccupiedBandwidth(
+      lastSpectrumData,
+      lastFreqHz,
+      mode,
+      mwDefaultsForMode(mode),
+      interference
+    );
     if (!Number.isFinite(estimated) || estimated <= 0) {
       syncBandwidthInput(currentBandwidthHz);
       return;
@@ -4178,7 +4183,6 @@ ${unsupportedBandSummary()}`;
     if (lastSpectrumData) {
       scheduleSpectrumDraw();
     }
-    const mode = (modeEl?.value || "").toUpperCase();
     let reason = "measured occupied spectrum";
     if (mode === "WFM") {
       if (estimated === 6e4 && lastWfmAci >= 20) reason = `high adjacent-channel interference (${Math.round(lastWfmAci)}% ACI)`;
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js
index bdaf449b..f7eac405 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.js
@@ -36,6 +36,7 @@ import {
   tabFromPath as tabFromPathname,
   updateTabHistory,
 } from "./features/navigation/routes.js";
+import { estimateOccupiedBandwidth } from "./features/radio/auto-bandwidth.js";
 
 // --- Decoder registry (fetched from /decoders on load) ---
 void loadDecoderRegistry(refreshOperatorLayoutCapabilities);
@@ -4109,110 +4110,20 @@ async function applyBandwidthFromInput() {
   }
 }
 
-function estimateOccupiedBandwidth(data, centerHz, interference = {}) {
-  if (!data || !isBinsArray(data.bins) || data.bins.length < 3 || !Number.isFinite(centerHz)) {
-    return null;
-  }
-
-  const bins = data.bins;
-  const maxIdx = bins.length - 1;
-  const hzPerBin = data.sample_rate / maxIdx;
-  const fullLoHz = data.center_hz - data.sample_rate / 2;
-  const centerIdx = Math.max(
-    1,
-    Math.min(maxIdx - 1, Math.round(((centerHz - fullLoHz) / data.sample_rate) * maxIdx)),
-  );
-  const mode = (modeEl ? modeEl.value : "USB").toUpperCase();
-  const [defaultBw, minBw, maxBw, stepBw] = mwDefaultsForMode(mode);
-  const oneSided = mode === "USB" || mode === "DIG" || mode === "CW"
-    ? 1
-    : mode === "LSB" || mode === "CWR" ? -1 : 0;
-  const isWfm = mode === "WFM";
-
-  // Reduce single-bin peaks and holes before finding occupied-channel edges.
-  // WFM needs a wider smoothing window because its energy is noise-like and
-  // spread across the entire channel rather than concentrated at a carrier.
-  const smoothRadius = isWfm ? 3 : 1;
-  const smoothed = bins.map((_, i) => {
-    let sum = 0;
-    let count = 0;
-    for (let j = Math.max(0, i - smoothRadius); j <= Math.min(maxIdx, i + smoothRadius); j++) {
-      sum += bins[j];
-      count += 1;
-    }
-    return sum / count;
-  });
-  const sorted = [...bins].sort((a, b) => a - b);
-  const noise = sorted[Math.floor(sorted.length * 0.2)];
-  const maxSpanBins = Math.max(2, Math.ceil(maxBw / hzPerBin));
-  const searchHalfBins = oneSided === 0 ? Math.ceil(maxSpanBins / 2) : maxSpanBins;
-  const searchLo = Math.max(1, centerIdx - (oneSided > 0 ? 2 : searchHalfBins));
-  const searchHi = Math.min(maxIdx - 1, centerIdx + (oneSided < 0 ? 2 : searchHalfBins));
-  let peak = -Infinity;
-  for (let i = searchLo; i <= searchHi; i++) peak = Math.max(peak, smoothed[i]);
-  const snr = peak - noise;
-  if (!Number.isFinite(snr) || snr < (isWfm ? 5 : 4)) return isWfm ? minBw : defaultBw;
-
-  // A threshold relative to the noise floor finds occupied bandwidth much
-  // more reliably than one relative to the peak.  The latter fails for WFM,
-  // whose multiplex spectrum has peaks, notches, and no narrow centre carrier.
-  const threshold = noise + Math.max(3, Math.min(isWfm ? 6 : 10, snr * (isWfm ? 0.18 : 0.28)));
-  const allowedGap = Math.max(isWfm ? 4 : 2, Math.ceil((isWfm ? 12_000 : stepBw) / hzPerBin));
-
-  function occupiedExtent(direction, limitBins) {
-    let lastOccupied = centerIdx;
-    let gap = 0;
-    for (let n = 0; n <= limitBins; n++) {
-      const i = centerIdx + direction * n;
-      if (i <= 0 || i >= maxIdx) break;
-      if (smoothed[i] >= threshold) {
-        lastOccupied = i;
-        gap = 0;
-      } else if (++gap > allowedGap) {
-        break;
-      }
-    }
-    return Math.abs(lastOccupied - centerIdx) * hzPerBin;
-  }
-
-  let rawBw;
-  if (oneSided !== 0) {
-    rawBw = occupiedExtent(oneSided, maxSpanBins);
-  } else {
-    const leftHz = occupiedExtent(-1, searchHalfBins);
-    const rightHz = occupiedExtent(1, searchHalfBins);
-    // A symmetric RF filter must contain the larger of the two sidebands.
-    rawBw = 2 * Math.max(leftHz, rightHz);
-  }
-
-  // Add a transition-band margin.  Weak WFM deliberately falls back to the
-  // 60 kHz mode floor above: a narrower filter trades stereo/RDS content for
-  // a useful improvement in intelligibility when the signal is very poor.
-  rawBw *= isWfm ? 1.08 : 1.12;
-  if (isWfm) {
-    const aci = Math.max(0, Math.min(100, Number(interference.aci) || 0)) / 100;
-    const cci = Math.max(0, Math.min(100, Number(interference.cci) || 0)) / 100;
-    // Adjacent-channel energy is outside the wanted modulation, so ACI can
-    // safely drive the cap all the way from the 300 kHz ceiling to 60 kHz.
-    const aciCap = maxBw - (maxBw - minBw) * aci;
-    // CCI overlaps the wanted station and cannot be removed by an RF filter.
-    // Only distrust the widest edge estimates, retaining at least 65% of the
-    // useful range between the weak-signal floor and nominal WFM bandwidth.
-    const cciFloor = minBw + (defaultBw - minBw) * 0.65;
-    const cciCap = maxBw - (maxBw - cciFloor) * cci;
-    rawBw = Math.min(rawBw, aciCap, cciCap);
-  }
-  const clamped = Math.max(minBw, Math.min(maxBw, rawBw));
-  return Math.max(stepBw, Math.round(clamped / stepBw) * stepBw);
-}
-
 async function applyAutoBandwidth() {
   if (!lastSpectrumData || lastFreqHz == null) return;
   // WFM interference telemetry belongs to the primary DSP channel. Do not
   // apply it to a virtual channel, where it would describe the wrong signal.
   const onVirtual = window.trx.modules.vchan?.isOnVirtual() === true;
   const interference = onVirtual ? {} : { cci: lastWfmCci, aci: lastWfmAci };
-  const estimated = estimateOccupiedBandwidth(lastSpectrumData, lastFreqHz, interference);
+  const mode = (modeEl?.value || "").toUpperCase();
+  const estimated = estimateOccupiedBandwidth(
+    lastSpectrumData,
+    lastFreqHz,
+    mode,
+    mwDefaultsForMode(mode),
+    interference,
+  );
   if (!Number.isFinite(estimated) || estimated <= 0) {
     syncBandwidthInput(currentBandwidthHz);
     return;
@@ -4224,7 +4135,6 @@ async function applyAutoBandwidth() {
   if (lastSpectrumData) {
     scheduleSpectrumDraw();
   }
-  const mode = (modeEl?.value || "").toUpperCase();
   let reason = "measured occupied spectrum";
   if (mode === "WFM") {
     if (estimated === 60_000 && lastWfmAci >= 20) reason = `high adjacent-channel interference (${Math.round(lastWfmAci)}% ACI)`;
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/features/radio/auto-bandwidth.ts b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/features/radio/auto-bandwidth.ts
new file mode 100644
index 00000000..6845db79
--- /dev/null
+++ b/src/trx-client/trx-frontend/trx-frontend-http/frontend/src/features/radio/auto-bandwidth.ts
@@ -0,0 +1,97 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+export interface SpectrumFrame {
+  bins: readonly number[] | ArrayBufferView;
+  center_hz: number;
+  sample_rate: number;
+}
+
+export interface InterferenceLevels { aci?: number; cci?: number }
+export type BandwidthLimits = readonly [defaultHz: number, minHz: number, maxHz: number, stepHz: number];
+
+function clampPercent(value: unknown): number {
+  const numeric = Number(value) || 0;
+  return Math.max(0, Math.min(100, numeric)) / 100;
+}
+
+export function estimateOccupiedBandwidth(
+  data: SpectrumFrame | null,
+  centerHz: number,
+  mode: string,
+  limits: BandwidthLimits,
+  interference: InterferenceLevels = {},
+): number | null {
+  if (!data || !Array.isArray(data.bins) && !ArrayBuffer.isView(data.bins)
+    || !Number.isFinite(centerHz)) return null;
+
+  const bins = Array.from(data.bins as ArrayLike<number>);
+  if (bins.length < 3) return null;
+  const maxIdx = bins.length - 1;
+  const hzPerBin = data.sample_rate / maxIdx;
+  const fullLoHz = data.center_hz - data.sample_rate / 2;
+  const centerIdx = Math.max(
+    1,
+    Math.min(maxIdx - 1, Math.round(((centerHz - fullLoHz) / data.sample_rate) * maxIdx)),
+  );
+  const normalizedMode = mode.toUpperCase();
+  const [defaultBw, minBw, maxBw, stepBw] = limits;
+  const oneSided = ["USB", "DIG", "CW"].includes(normalizedMode)
+    ? 1 : ["LSB", "CWR"].includes(normalizedMode) ? -1 : 0;
+  const isWfm = normalizedMode === "WFM";
+  const smoothRadius = isWfm ? 3 : 1;
+  const smoothed = bins.map((_, index) => {
+    let sum = 0;
+    let count = 0;
+    for (let adjacent = Math.max(0, index - smoothRadius);
+      adjacent <= Math.min(maxIdx, index + smoothRadius); adjacent += 1) {
+      sum += bins[adjacent] ?? 0;
+      count += 1;
+    }
+    return sum / count;
+  });
+  const sorted = [...bins].sort((left, right) => left - right);
+  const noise = sorted[Math.floor(sorted.length * 0.2)] ?? -Infinity;
+  const maxSpanBins = Math.max(2, Math.ceil(maxBw / hzPerBin));
+  const searchHalfBins = oneSided === 0 ? Math.ceil(maxSpanBins / 2) : maxSpanBins;
+  const searchLo = Math.max(1, centerIdx - (oneSided > 0 ? 2 : searchHalfBins));
+  const searchHi = Math.min(maxIdx - 1, centerIdx + (oneSided < 0 ? 2 : searchHalfBins));
+  let peak = -Infinity;
+  for (let index = searchLo; index <= searchHi; index += 1) {
+    peak = Math.max(peak, smoothed[index] ?? -Infinity);
+  }
+  const snr = peak - noise;
+  if (!Number.isFinite(snr) || snr < (isWfm ? 5 : 4)) return isWfm ? minBw : defaultBw;
+
+  const threshold = noise + Math.max(3, Math.min(isWfm ? 6 : 10, snr * (isWfm ? 0.18 : 0.28)));
+  const allowedGap = Math.max(isWfm ? 4 : 2, Math.ceil((isWfm ? 12_000 : stepBw) / hzPerBin));
+  const occupiedExtent = (direction: -1 | 1, limitBins: number): number => {
+    let lastOccupied = centerIdx;
+    let gap = 0;
+    for (let offset = 0; offset <= limitBins; offset += 1) {
+      const index = centerIdx + direction * offset;
+      if (index <= 0 || index >= maxIdx) break;
+      if ((smoothed[index] ?? -Infinity) >= threshold) {
+        lastOccupied = index;
+        gap = 0;
+      } else if (++gap > allowedGap) break;
+    }
+    return Math.abs(lastOccupied - centerIdx) * hzPerBin;
+  };
+
+  let rawBw = oneSided !== 0
+    ? occupiedExtent(oneSided, maxSpanBins)
+    : 2 * Math.max(occupiedExtent(-1, searchHalfBins), occupiedExtent(1, searchHalfBins));
+  rawBw *= isWfm ? 1.08 : 1.12;
+  if (isWfm) {
+    const aci = clampPercent(interference.aci);
+    const cci = clampPercent(interference.cci);
+    const aciCap = maxBw - (maxBw - minBw) * aci;
+    const cciFloor = minBw + (defaultBw - minBw) * 0.65;
+    const cciCap = maxBw - (maxBw - cciFloor) * cci;
+    rawBw = Math.min(rawBw, aciCap, cciCap);
+  }
+  const clamped = Math.max(minBw, Math.min(maxBw, rawBw));
+  return Math.max(stepBw, Math.round(clamped / stepBw) * stepBw);
+}
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/auto-bandwidth.test.mjs b/src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/auto-bandwidth.test.mjs
new file mode 100644
index 00000000..3fe59eee
--- /dev/null
+++ b/src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/auto-bandwidth.test.mjs
@@ -0,0 +1,56 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+import assert from "node:assert/strict";
+import test from "node:test";
+import vm from "node:vm";
+import { build } from "esbuild";
+
+async function loadEstimator() {
+  const result = await build({
+    entryPoints: [new URL("../src/features/radio/auto-bandwidth.ts", import.meta.url).pathname],
+    bundle: true,
+    format: "cjs",
+    platform: "browser",
+    target: "es2022",
+    write: false,
+  });
+  const module = { exports: {} };
+  vm.runInNewContext(result.outputFiles[0].text, {
+    module,
+    exports: module.exports,
+    Array,
+    ArrayBuffer,
+    Number,
+    Math,
+  });
+  return module.exports.estimateOccupiedBandwidth;
+}
+
+function wfmFrame(signalHalfWidthHz, signalDb = -70) {
+  const sampleRate = 400_000;
+  const bins = Array.from({ length: 1025 }, (_, index) => {
+    const offsetHz = (index / 1024 - 0.5) * sampleRate;
+    return Math.abs(offsetHz) <= signalHalfWidthHz ? signalDb : -100;
+  });
+  return { bins, center_hz: 100_000_000, sample_rate: sampleRate };
+}
+
+test("weak WFM falls back to the 60 kHz intelligibility floor", async () => {
+  const estimate = await loadEstimator();
+  const weak = wfmFrame(90_000, -97);
+  assert.equal(estimate(weak, 100_000_000, "WFM", [180_000, 60_000, 300_000, 5_000]), 60_000);
+});
+
+test("WFM ACI and CCI cap an otherwise wide occupied estimate", async () => {
+  const estimate = await loadEstimator();
+  const frame = wfmFrame(95_000);
+  const limits = [180_000, 60_000, 300_000, 5_000];
+  const clear = estimate(frame, 100_000_000, "WFM", limits);
+  const adjacent = estimate(frame, 100_000_000, "WFM", limits, { aci: 100 });
+  const cochannel = estimate(frame, 100_000_000, "WFM", limits, { cci: 100 });
+  assert.ok(clear > adjacent);
+  assert.equal(adjacent, 60_000);
+  assert.ok(cochannel >= 135_000 && cochannel < clear);
+});