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 c88802b..3c99ee5 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
@@ -4249,10 +4249,93 @@ function drawSpectrum(data) {
     ctx.restore();
   }
 
+  // ── Bookmark frequency markers ─────────────────────────────────────────────
+  const visBookmarks = Array.isArray(window.bmList)
+    ? window.bmList.filter((bm) => bm.freq_hz >= range.visLoHz && bm.freq_hz <= range.visHiHz)
+    : [];
+  if (visBookmarks.length > 0) {
+    ctx.save();
+    // Thin amber vertical line from top of canvas down to the ribbon
+    const BM_RIBBON_H = 14 * dpr; // height of the bookmark ribbon shape
+    const BM_RIBBON_W = 8 * dpr;  // half-width of the ribbon
+    ctx.strokeStyle = "rgba(246,173,85,0.70)";
+    ctx.lineWidth = 1 * dpr;
+    for (const bm of visBookmarks) {
+      const x = hzToX(bm.freq_hz);
+      ctx.beginPath();
+      ctx.moveTo(x, 0);
+      ctx.lineTo(x, H - BM_RIBBON_H);
+      ctx.stroke();
+    }
+    // Bookmark ribbon shape: rectangle with V-notch cut from the bottom
+    for (const bm of visBookmarks) {
+      const x = hzToX(bm.freq_hz);
+      const top = H - BM_RIBBON_H;
+      const bot = H;
+      const notchDepth = 4 * dpr; // depth of the V notch
+      ctx.fillStyle = "rgba(246,173,85,0.92)";
+      ctx.strokeStyle = "rgba(180,100,20,0.60)";
+      ctx.lineWidth = 0.75 * dpr;
+      ctx.beginPath();
+      ctx.moveTo(x - BM_RIBBON_W, top);
+      ctx.lineTo(x + BM_RIBBON_W, top);
+      ctx.lineTo(x + BM_RIBBON_W, bot - notchDepth);
+      ctx.lineTo(x, bot);               // V notch point
+      ctx.lineTo(x - BM_RIBBON_W, bot - notchDepth);
+      ctx.closePath();
+      ctx.fill();
+      ctx.stroke();
+    }
+    ctx.restore();
+  }
+
   updateSpectrumFreqAxis(range);
+  updateBookmarkAxis(range);
   drawSignalOverlay();
 }
 
+function updateBookmarkAxis(range) {
+  const axisEl = document.getElementById("spectrum-bookmark-axis");
+  const freqAxisEl = document.getElementById("spectrum-freq-axis");
+  if (!axisEl) return;
+
+  const visBookmarks = Array.isArray(window.bmList)
+    ? window.bmList.filter((bm) => bm.freq_hz >= range.visLoHz && bm.freq_hz <= range.visHiHz)
+    : [];
+
+  const hasVisible = visBookmarks.length > 0;
+  axisEl.classList.toggle("bm-axis-visible", hasVisible);
+  if (freqAxisEl) freqAxisEl.classList.toggle("bm-axis-open", hasVisible);
+  axisEl.innerHTML = "";
+  if (!hasVisible) return;
+
+  const axisWidth = axisEl.clientWidth || 0;
+  const edgePad = 6;
+  for (const bm of visBookmarks) {
+    const frac = (bm.freq_hz - range.visLoHz) / range.visSpanHz;
+    const span = document.createElement("span");
+    span.textContent = bm.name;
+    span.title =
+      bm.name +
+      " \u2014 " +
+      (typeof bmFmtFreq === "function" ? bmFmtFreq(bm.freq_hz) : bm.freq_hz + "\u202fHz");
+    span.dataset.bmId = bm.id;
+    span.addEventListener("click", () => {
+      if (typeof bmApply === "function") bmApply(bm);
+    });
+    axisEl.appendChild(span);
+    if (axisWidth > 0) {
+      const labelWidth = span.offsetWidth || 0;
+      const minCenter = edgePad + labelWidth / 2;
+      const maxCenter = axisWidth - edgePad - labelWidth / 2;
+      const clampedCenter = Math.max(minCenter, Math.min(maxCenter, frac * axisWidth));
+      span.style.left = clampedCenter + "px";
+    } else {
+      span.style.left = (frac * 100).toFixed(2) + "%";
+    }
+  }
+}
+
 function updateSpectrumFreqAxis(range) {
   if (!spectrumFreqAxis) return;
   const spanHz = range.visSpanHz;
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 6097b70..f30a37e 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
@@ -82,6 +82,7 @@
           <canvas id="spectrum-canvas"></canvas>
           <div id="spectrum-tooltip"></div>
           <div id="spectrum-freq-axis"></div>
+          <div id="spectrum-bookmark-axis"></div>
         </div>
         <div id="spectrum-controls">
           <div id="spectrum-bw-row">
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/bookmarks.js b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/bookmarks.js
index eaec54c..24a738f 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/bookmarks.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/bookmarks.js
@@ -46,6 +46,7 @@ async function bmFetch(categoryFilter) {
   bmSyncAccess();
   bmRender(bmList);
   bmRefreshCategoryFilter(categoryFilter);
+  if (typeof scheduleSpectrumDraw === "function") scheduleSpectrumDraw();
 }
 
 async function bmRefreshCategoryFilter(keepValue) {
@@ -197,6 +198,9 @@ async function bmSave(e) {
     }
     if (!resp.ok) {
       const text = await resp.text();
+      if (resp.status === 409) {
+        throw new Error("A bookmark for that frequency already exists.");
+      }
       throw new Error(text || "HTTP " + resp.status);
     }
     bmCloseForm();
@@ -294,4 +298,7 @@ async function bmApply(bm) {
       await bmDelete(delBtn.dataset.bmId);
     }
   });
+
+  // Pre-load bookmarks so spectrum markers are visible immediately.
+  bmFetch("");
 })();
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 9419e5e..c23585e 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
@@ -1516,6 +1516,50 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   top: 2px;
   font-weight: 700;
 }
+#spectrum-freq-axis.bm-axis-open {
+  border-radius: 0;
+  border-bottom-color: transparent;
+}
+#spectrum-bookmark-axis {
+  position: relative;
+  height: 0;
+  overflow: hidden;
+  width: 100%;
+  font-size: 0.68rem;
+  background: var(--bg-secondary);
+  border-radius: 0 0 6px 6px;
+  border: 1px solid var(--border);
+  border-top: none;
+  transition: height 80ms ease;
+}
+#spectrum-bookmark-axis.bm-axis-visible {
+  height: 22px;
+}
+#spectrum-bookmark-axis span {
+  position: absolute;
+  transform: translateX(-50%);
+  white-space: nowrap;
+  top: 3px;
+  cursor: pointer;
+  font-weight: 600;
+  font-size: 0.66rem;
+  /* amber bookmark-ribbon appearance */
+  background: rgba(246,173,85,0.18);
+  color: #c07320;
+  border: 1px solid rgba(246,173,85,0.55);
+  border-radius: 3px 3px 0 0;
+  padding: 1px 5px 0;
+  /* clip the bottom into a V-notch bookmark shape */
+  clip-path: polygon(0 0, 100% 0, 100% 70%, 50% 100%, 0 70%);
+  max-width: 110px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  line-height: 1.5;
+}
+#spectrum-bookmark-axis span:hover {
+  background: rgba(246,173,85,0.38);
+  color: #7a4a00;
+}
 #spectrum-tooltip {
   display: none;
   position: absolute;
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs b/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs
index 7392bb8..ddd67bd 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs
+++ b/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs
@@ -735,6 +735,11 @@ pub async fn create_bookmark(
     auth_state: web::Data<crate::server::auth::AuthState>,
 ) -> Result<HttpResponse, Error> {
     require_control(&req, &auth_state)?;
+    if store.freq_taken(body.freq_hz, None) {
+        return Err(actix_web::error::ErrorConflict(
+            "a bookmark for that frequency already exists",
+        ));
+    }
     let bm = crate::server::bookmarks::Bookmark {
         id: gen_bookmark_id(),
         name: body.name.clone(),
@@ -764,6 +769,11 @@ pub async fn update_bookmark(
 ) -> Result<HttpResponse, Error> {
     require_control(&req, &auth_state)?;
     let id = path.into_inner();
+    if store.freq_taken(body.freq_hz, Some(&id)) {
+        return Err(actix_web::error::ErrorConflict(
+            "a bookmark for that frequency already exists",
+        ));
+    }
     let bm = crate::server::bookmarks::Bookmark {
         id: id.clone(),
         name: body.name.clone(),
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/src/bookmarks.rs b/src/trx-client/trx-frontend/trx-frontend-http/src/bookmarks.rs
index 9aec2b2..36f277f 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/src/bookmarks.rs
+++ b/src/trx-client/trx-frontend/trx-frontend-http/src/bookmarks.rs
@@ -91,4 +91,11 @@ impl BookmarkStore {
         let mut db = self.db.write().unwrap_or_else(|e| e.into_inner());
         db.rem(&format!("bm:{id}")).unwrap_or(false)
     }
+
+    /// Returns true if any bookmark (other than `exclude_id`) has `freq_hz`.
+    pub fn freq_taken(&self, freq_hz: u64, exclude_id: Option<&str>) -> bool {
+        self.list().into_iter().any(|bm| {
+            bm.freq_hz == freq_hz && exclude_id.map_or(true, |ex| bm.id != ex)
+        })
+    }
 }