diff --git a/static/js/modes/sstv-general.js b/static/js/modes/sstv-general.js
index 444ef0a..f023f0a 100644
--- a/static/js/modes/sstv-general.js
+++ b/static/js/modes/sstv-general.js
@@ -245,7 +245,14 @@ const SSTVGeneral = (function() {
             renderGallery();
             showNotification('SSTV', 'New image decoded!');
             updateStatusUI('listening', 'Listening...');
+            // Clear decode progress so signal monitor can take over
+            const liveContent = document.getElementById('sstvGeneralLiveContent');
+            if (liveContent) liveContent.innerHTML = '';
         } else if (data.status === 'detecting') {
+            // Ignore detecting events if currently decoding (e.g. Doppler updates)
+            const dot = document.getElementById('sstvGeneralStripDot');
+            if (dot && dot.classList.contains('decoding')) return;
+
             updateStatusUI('listening', data.message || 'Listening...');
             if (data.signal_level !== undefined) {
                 renderSignalMonitor(data);
diff --git a/static/js/modes/sstv.js b/static/js/modes/sstv.js
index 2830f8a..2d02a24 100644
--- a/static/js/modes/sstv.js
+++ b/static/js/modes/sstv.js
@@ -680,7 +680,14 @@ const SSTV = (function() {
             renderGallery();
             showNotification('SSTV', 'New image decoded!');
             updateStatusUI('listening', 'Listening...');
+            // Clear decode progress so signal monitor can take over
+            const liveContent = document.getElementById('sstvLiveContent');
+            if (liveContent) liveContent.innerHTML = '';
         } else if (data.status === 'detecting') {
+            // Ignore detecting events if currently decoding (e.g. Doppler updates)
+            const dot = document.getElementById('sstvStripDot');
+            if (dot && dot.classList.contains('decoding')) return;
+
             updateStatusUI('listening', data.message || 'Listening...');
             if (data.signal_level !== undefined) {
                 renderSignalMonitor(data);
diff --git a/utils/sstv/sstv_decoder.py b/utils/sstv/sstv_decoder.py
index 368edac..3035adc 100644
--- a/utils/sstv/sstv_decoder.py
+++ b/utils/sstv/sstv_decoder.py
@@ -92,8 +92,8 @@ class DecodeProgress:
     progress_percent: int = 0
     message: str | None = None
     image: SSTVImage | None = None
-    signal_level: int = 0          # 0-100 RMS audio level
-    sstv_tone: str | None = None   # 'leader', 'sync', 'pixel', None
+    signal_level: int | None = None  # 0-100 RMS audio level, None = not measured
+    sstv_tone: str | None = None     # 'leader', 'sync', 'noise', None
 
     def to_dict(self) -> dict:
         result: dict = {
@@ -107,10 +107,10 @@ class DecodeProgress:
             result['message'] = self.message
         if self.image:
             result['image'] = self.image.to_dict()
-        if self.status == 'detecting':
+        if self.signal_level is not None:
             result['signal_level'] = self.signal_level
-            if self.sstv_tone:
-                result['sstv_tone'] = self.sstv_tone
+        if self.sstv_tone:
+            result['sstv_tone'] = self.sstv_tone
         return result