diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js
index 698fccf..31a11f0 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js
@@ -284,10 +284,12 @@ function applyCapabilities(caps) {
   if (spectrumPanel) {
     if (caps.filter_controls) {
       spectrumPanel.style.display = "";
+      setSignalSplitControlVisible(true);
       if (centerFreqField) centerFreqField.style.display = "";
       startSpectrumStreaming();
     } else {
       spectrumPanel.style.display = "none";
+      setSignalSplitControlVisible(false);
       if (centerFreqField) centerFreqField.style.display = "none";
       stopSpectrumStreaming();
     }
@@ -325,6 +327,9 @@ const loadingSub = document.getElementById("loading-sub");
 const overviewCanvas = document.getElementById("overview-canvas");
 const signalOverlayCanvas = document.getElementById("signal-overlay-canvas");
 const signalVisualBlockEl = document.querySelector(".signal-visual-block");
+const signalSplitControlEl = document.getElementById("signal-split-control");
+const signalSplitSliderEl = document.getElementById("signal-split-slider");
+const signalSplitValueEl = document.getElementById("signal-split-value");
 const overviewPeakHoldEl = document.getElementById("overview-peak-hold");
 const themeToggleBtn = document.getElementById("theme-toggle");
 const headerRigSwitchSelect = document.getElementById("header-rig-switch-select");
@@ -1932,10 +1937,17 @@ let spectrumCoverageMarginHz = 50_000;
 let spectrumUsableSpanRatio = 0.92;
 const DEFAULT_OVERVIEW_PLOT_HEIGHT_PX = 160;
 const DEFAULT_SPECTRUM_PLOT_HEIGHT_PX = 160;
+const MIN_OVERVIEW_PLOT_HEIGHT_PX = 90;
 const MIN_SPECTRUM_PLOT_HEIGHT_PX = 130;
+const DEFAULT_SIGNAL_SPLIT_PERCENT = 50;
+const MIN_SIGNAL_SPLIT_PERCENT = 20;
+const MAX_SIGNAL_SPLIT_PERCENT = 80;
 let spectrumLayoutPending = false;
-let spectrumManualPlotHeightPx = null;
+let spectrumManualTotalPlotHeightPx = null;
 let spectrumResizeState = null;
+let signalSplitPercent = clampSignalSplitPercent(
+  Number(loadSetting("signalSplitPercent", DEFAULT_SIGNAL_SPLIT_PERCENT)),
+);
 
 function updateFooterBuildInfo() {
   const serverEl = document.getElementById("footer-server-build");
@@ -1954,6 +1966,31 @@ function scheduleSpectrumLayout() {
   });
 }
 
+function clampSignalSplitPercent(value) {
+  const numeric = Number.isFinite(value) ? value : DEFAULT_SIGNAL_SPLIT_PERCENT;
+  return Math.max(
+    MIN_SIGNAL_SPLIT_PERCENT,
+    Math.min(MAX_SIGNAL_SPLIT_PERCENT, Math.round(numeric)),
+  );
+}
+
+function updateSignalSplitControlText() {
+  if (!signalSplitValueEl) return;
+  signalSplitValueEl.textContent = `${signalSplitPercent}/${100 - signalSplitPercent}`;
+}
+
+function setSignalSplitControlVisible(visible) {
+  if (!signalSplitControlEl) return;
+  signalSplitControlEl.style.display = visible ? "flex" : "none";
+}
+
+function currentOverviewHeightPx(overviewCanvasEl) {
+  return Math.max(
+    MIN_OVERVIEW_PLOT_HEIGHT_PX,
+    Math.round(overviewCanvasEl?.clientHeight || DEFAULT_OVERVIEW_PLOT_HEIGHT_PX),
+  );
+}
+
 function currentSpectrumHeightPx(spectrumCanvasEl) {
   return Math.max(
     MIN_SPECTRUM_PLOT_HEIGHT_PX,
@@ -1961,18 +1998,21 @@ function currentSpectrumHeightPx(spectrumCanvasEl) {
   );
 }
 
-function spectrumHeightBoundsPx(tabMainEl, contentEl, spectrumCanvasEl) {
+function spectrumHeightBoundsPx(tabMainEl, contentEl, overviewCanvasEl, spectrumCanvasEl) {
+  const currentOverviewHeight = currentOverviewHeightPx(overviewCanvasEl);
   const currentSpectrumHeight = currentSpectrumHeightPx(spectrumCanvasEl);
+  const currentTotalHeight = currentOverviewHeight + currentSpectrumHeight;
   const tabBottom = tabMainEl.getBoundingClientRect().bottom;
   const contentBottom = contentEl.getBoundingClientRect().bottom;
   const slackPx = Math.floor(tabBottom - contentBottom);
-  const maxHeight = Math.max(
-    MIN_SPECTRUM_PLOT_HEIGHT_PX,
-    currentSpectrumHeight + slackPx - 2,
+  const minTotalHeight = MIN_OVERVIEW_PLOT_HEIGHT_PX + MIN_SPECTRUM_PLOT_HEIGHT_PX;
+  const maxAutoTotalHeight = Math.max(
+    minTotalHeight,
+    currentTotalHeight + slackPx - 2,
   );
   return {
-    min: MIN_SPECTRUM_PLOT_HEIGHT_PX,
-    max: maxHeight,
+    minTotal: minTotalHeight,
+    autoMaxTotal: maxAutoTotalHeight,
   };
 }
 
@@ -1988,16 +2028,11 @@ function updateSpectrumAutoHeight() {
   const mainVisible = getComputedStyle(tabMainEl).display !== "none";
   const contentVisible = getComputedStyle(contentEl).display !== "none";
   const spectrumVisible = getComputedStyle(spectrumPanelEl).display !== "none";
-  const currentOverviewHeight = Math.max(
-    DEFAULT_OVERVIEW_PLOT_HEIGHT_PX,
-    Math.round(overviewCanvasEl.clientHeight || DEFAULT_OVERVIEW_PLOT_HEIGHT_PX),
-  );
-  const currentSpectrumHeight = Math.max(
-    DEFAULT_SPECTRUM_PLOT_HEIGHT_PX,
-    Math.round(spectrumCanvasEl.clientHeight || DEFAULT_SPECTRUM_PLOT_HEIGHT_PX),
-  );
+  const currentOverviewHeight = currentOverviewHeightPx(overviewCanvasEl);
+  const currentSpectrumHeight = currentSpectrumHeightPx(spectrumCanvasEl);
 
   if (!mainVisible || !contentVisible || !spectrumVisible) {
+    setSignalSplitControlVisible(false);
     root.style.setProperty("--overview-plot-height", `${DEFAULT_OVERVIEW_PLOT_HEIGHT_PX}px`);
     root.style.setProperty("--spectrum-plot-height", `${DEFAULT_SPECTRUM_PLOT_HEIGHT_PX}px`);
     if (
@@ -2011,19 +2046,29 @@ function updateSpectrumAutoHeight() {
     return;
   }
 
-  const bounds = spectrumHeightBoundsPx(tabMainEl, contentEl, spectrumCanvasEl);
-  const nextSpectrumHeight = spectrumManualPlotHeightPx == null
-    ? bounds.max
-    : Math.max(bounds.min, Math.round(spectrumManualPlotHeightPx));
-  if (spectrumManualPlotHeightPx != null) {
-    spectrumManualPlotHeightPx = nextSpectrumHeight;
+  setSignalSplitControlVisible(true);
+  const bounds = spectrumHeightBoundsPx(tabMainEl, contentEl, overviewCanvasEl, spectrumCanvasEl);
+  const nextTotalHeight = spectrumManualTotalPlotHeightPx == null
+    ? bounds.autoMaxTotal
+    : Math.max(bounds.minTotal, Math.round(spectrumManualTotalPlotHeightPx));
+  if (spectrumManualTotalPlotHeightPx != null) {
+    spectrumManualTotalPlotHeightPx = nextTotalHeight;
   }
+  const requestedOverviewHeight = Math.round((nextTotalHeight * signalSplitPercent) / 100);
+  const nextOverviewHeight = Math.max(
+    MIN_OVERVIEW_PLOT_HEIGHT_PX,
+    Math.min(nextTotalHeight - MIN_SPECTRUM_PLOT_HEIGHT_PX, requestedOverviewHeight),
+  );
+  const nextSpectrumHeight = Math.max(
+    MIN_SPECTRUM_PLOT_HEIGHT_PX,
+    nextTotalHeight - nextOverviewHeight,
+  );
   if (
-    Math.abs(DEFAULT_OVERVIEW_PLOT_HEIGHT_PX - currentOverviewHeight) < 2
+    Math.abs(nextOverviewHeight - currentOverviewHeight) < 2
     && Math.abs(nextSpectrumHeight - currentSpectrumHeight) < 2
   ) return;
 
-  root.style.setProperty("--overview-plot-height", `${DEFAULT_OVERVIEW_PLOT_HEIGHT_PX}px`);
+  root.style.setProperty("--overview-plot-height", `${nextOverviewHeight}px`);
   root.style.setProperty("--spectrum-plot-height", `${nextSpectrumHeight}px`);
   if (lastSpectrumData) {
     scheduleSpectrumDraw();
@@ -2034,16 +2079,20 @@ function updateSpectrumAutoHeight() {
 function beginSpectrumResize(clientY) {
   const tabMainEl = document.getElementById("tab-main");
   const contentEl = document.getElementById("content");
+  const overviewCanvasEl = document.getElementById("overview-canvas");
   const spectrumCanvasEl = document.getElementById("spectrum-canvas");
   const spectrumPanelEl = document.getElementById("spectrum-panel");
-  if (!tabMainEl || !contentEl || !spectrumCanvasEl || !spectrumPanelEl) return false;
+  if (!tabMainEl || !contentEl || !overviewCanvasEl || !spectrumCanvasEl || !spectrumPanelEl) return false;
   if (getComputedStyle(spectrumPanelEl).display === "none") return false;
-  const bounds = spectrumHeightBoundsPx(tabMainEl, contentEl, spectrumCanvasEl);
-  const startHeight = Math.max(bounds.min, currentSpectrumHeightPx(spectrumCanvasEl));
+  const bounds = spectrumHeightBoundsPx(tabMainEl, contentEl, overviewCanvasEl, spectrumCanvasEl);
+  const startTotalHeight = Math.max(
+    bounds.minTotal,
+    currentOverviewHeightPx(overviewCanvasEl) + currentSpectrumHeightPx(spectrumCanvasEl),
+  );
   spectrumResizeState = {
     startY: clientY,
-    startHeight,
-    minHeight: bounds.min,
+    startTotalHeight,
+    minTotalHeight: bounds.minTotal,
   };
   document.body.classList.add("spectrum-resizing");
   return true;
@@ -2052,9 +2101,9 @@ function beginSpectrumResize(clientY) {
 function updateSpectrumResize(clientY) {
   if (!spectrumResizeState) return;
   const deltaY = clientY - spectrumResizeState.startY;
-  spectrumManualPlotHeightPx = Math.max(
-    spectrumResizeState.minHeight,
-    Math.round(spectrumResizeState.startHeight + deltaY),
+  spectrumManualTotalPlotHeightPx = Math.max(
+    spectrumResizeState.minTotalHeight,
+    Math.round(spectrumResizeState.startTotalHeight + deltaY),
   );
   updateSpectrumAutoHeight();
 }
@@ -2088,11 +2137,23 @@ if (spectrumSizeGrip) {
   spectrumSizeGrip.addEventListener("pointerup", finishResize);
   spectrumSizeGrip.addEventListener("pointercancel", finishResize);
   spectrumSizeGrip.addEventListener("dblclick", () => {
-    spectrumManualPlotHeightPx = null;
+    spectrumManualTotalPlotHeightPx = null;
     scheduleSpectrumLayout();
   });
 }
 
+if (signalSplitSliderEl) {
+  signalSplitSliderEl.value = String(signalSplitPercent);
+  signalSplitSliderEl.addEventListener("input", () => {
+    signalSplitPercent = clampSignalSplitPercent(Number(signalSplitSliderEl.value));
+    signalSplitSliderEl.value = String(signalSplitPercent);
+    updateSignalSplitControlText();
+    saveSetting("signalSplitPercent", signalSplitPercent);
+    scheduleSpectrumLayout();
+  });
+}
+updateSignalSplitControlText();
+
 function updateTitle() {
   const titleEl = document.getElementById("rig-title");
   if (titleEl) {
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html
index 65e6537..8a9d6bb 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html
@@ -120,6 +120,10 @@
         <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</div>
         <div id="spectrum-hint-touch" class="spectrum-hint-touch">Pinch to zoom &middot; Drag to pan &middot; Drag BW edges to resize</div>
       </div>
+      <div id="signal-split-control" title="Set waterfall and waveform split" aria-label="Set waterfall and waveform split">
+        <input id="signal-split-slider" type="range" min="20" max="80" step="1" value="50" aria-label="Set waterfall and waveform split">
+        <span id="signal-split-value" aria-live="polite">50/50</span>
+      </div>
       <canvas id="signal-overlay-canvas" aria-hidden="true"></canvas>
     </div>
     <div class="status">
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css
index bbb150c..6ad5103 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css
@@ -529,6 +529,43 @@ small { color: var(--text-muted); }
   gap: 0;
   margin-bottom: 0.9rem;
 }
+#signal-split-control {
+  position: absolute;
+  top: 50%;
+  right: 0.32rem;
+  transform: translateY(-50%);
+  z-index: 9;
+  display: none;
+  flex-direction: column;
+  align-items: center;
+  gap: 0.3rem;
+  padding: 0.32rem 0.25rem;
+  border: 1px solid color-mix(in srgb, var(--border-light) 78%, transparent);
+  border-radius: 999px;
+  background: color-mix(in srgb, var(--card-bg) 78%, transparent);
+  backdrop-filter: blur(8px) saturate(125%);
+  -webkit-backdrop-filter: blur(8px) saturate(125%);
+  box-shadow:
+    0 8px 16px color-mix(in srgb, #000000 14%, transparent),
+    inset 0 1px 0 color-mix(in srgb, #ffffff 8%, transparent);
+}
+#signal-split-slider {
+  writing-mode: vertical-lr;
+  direction: rtl;
+  width: 0.95rem;
+  height: 7.2rem;
+  margin: 0;
+  accent-color: var(--accent-yellow);
+  cursor: ns-resize;
+}
+#signal-split-value {
+  min-width: 2.9rem;
+  text-align: center;
+  font-size: 0.64rem;
+  font-weight: 700;
+  letter-spacing: 0.04em;
+  color: var(--text-muted);
+}
 #signal-overlay-canvas {
   position: absolute;
   top: 0;
@@ -1805,6 +1842,22 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   .header-rig-switch { width: auto; justify-content: flex-end; }
   .header-rig-switch select { min-width: 6.5rem; }
   .overview-toolbar { top: calc(var(--header-waterfall-overlap) + 0.15rem); }
+  #signal-split-control {
+    top: 0.35rem;
+    right: 0.35rem;
+    transform: none;
+    flex-direction: row;
+    gap: 0.4rem;
+    border-radius: 0.7rem;
+    padding: 0.28rem 0.42rem;
+  }
+  #signal-split-slider {
+    writing-mode: horizontal-tb;
+    direction: ltr;
+    width: 5.5rem;
+    height: 1rem;
+    cursor: ew-resize;
+  }
   .controls-row { grid-template-columns: 1fr auto; }
   .controls-col-wfm { grid-column: 1 / -1; }
   .controls-col-power { grid-column: 1 / -1; }
@@ -2132,7 +2185,7 @@ button:focus-visible, input:focus-visible, select:focus-visible {
 }
 .spectrum-edge-shift {
   position: absolute;
-  top: calc(var(--spectrum-plot-height) / 2);
+  top: 50%;
   transform: translateY(-50%);
   z-index: 8;
   width: 1.7rem;
@@ -2261,7 +2314,7 @@ button:focus-visible, input:focus-visible, select:focus-visible {
 }
 .spectrum-bookmark-side {
   position: absolute;
-  top: calc(var(--spectrum-plot-height) / 2);
+  top: 50%;
   transform: translateY(-50%);
   z-index: 7;
   width: 7.25rem;