Fix TSCM section: timeline, RF scanning, and UI defaults

- Fix Signal Timeline not receiving events by using SignalTimeline.create()
  for TSCM mode to maintain backward compatibility with addEvent() calls
- Lower RF detection thresholds for RTL-SDR compatibility (6dB margin,
  -90dBm floor instead of 10dB/-70dBm)
- Reduce RF scan interval from 60s to 30s for quicker feedback
- Enable RF/SDR checkbox by default to match WiFi and Bluetooth
- Update status message when no signals detected

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

routes/tscm.py

@@ -1152,11 +1152,12 @@ def _scan_rf_signals(sdr_device: int | None, duration: int = 30) -> list[dict]:
                                     db_values = [float(x) for x in parts[6:] if x.strip()]
 
                                     # Find peaks above noise floor
+                                    # RTL-SDR dongles have higher noise figures, so use permissive thresholds
                                     noise_floor = sum(db_values) / len(db_values) if db_values else -100
-                                    threshold = noise_floor + 10  # Signal must be 10dB above noise
+                                    threshold = noise_floor + 6  # Signal must be 6dB above noise
 
                                     for idx, db in enumerate(db_values):
-                                        if db > threshold and db > -70:  # Detect signals above -70dBm
+                                        if db > threshold and db > -90:  # Detect signals above -90dBm
                                             freq_hz = hz_low + (idx * hz_step)
                                             freq_mhz = freq_hz / 1000000
 
@@ -1262,7 +1263,7 @@ def _run_sweep(
         last_rf_scan = 0
         wifi_scan_interval = 15  # Scan WiFi every 15 seconds
         bt_scan_interval = 20   # Scan Bluetooth every 20 seconds
-        rf_scan_interval = 60   # Scan RF every 60 seconds (it's slower)
+        rf_scan_interval = 30   # Scan RF every 30 seconds
 
         while _sweep_running and (time.time() - start_time) < duration:
             current_time = time.time()
@@ -1403,7 +1404,7 @@ def _run_sweep(
                     if not rf_signals and last_rf_scan == 0:
                         _emit_event('rf_status', {
                             'status': 'no_signals',
-                            'message': 'RF scan completed but no signals detected. Check RTL-SDR connection.',
+                            'message': 'RF scan completed - no signals above threshold. This may be normal in a quiet RF environment.',
                         })
 
                     for signal in rf_signals:

templates/index.html

@@ -1648,7 +1648,12 @@
             if (!container) return;
 
             // Create timeline using new ActivityTimeline
-            if (typeof ActivityTimeline !== 'undefined') {
+            // For TSCM mode, use SignalTimeline.create() to ensure backward compatibility
+            // with SignalTimeline.addEvent() calls used in TSCM event handlers
+            if (mode === 'tscm' && typeof SignalTimeline !== 'undefined') {
+                SignalTimeline.create(modeConfig.container, modeConfig.config);
+                modeTimelines[mode] = { addEvent: (e) => SignalTimeline.addEvent(e.id, e.strength, e.duration, e.label) };
+            } else if (typeof ActivityTimeline !== 'undefined') {
                 modeTimelines[mode] = ActivityTimeline.create(modeConfig.container, modeConfig.config);
             }
         }

templates/partials/modes/tscm.html

@@ -52,7 +52,7 @@
                             </div>
                             <div class="form-group" style="margin-bottom: 8px;">
                                 <label class="inline-checkbox">
-                                    <input type="checkbox" id="tscmRfEnabled">
+                                    <input type="checkbox" id="tscmRfEnabled" checked>
                                     RF/SDR
                                 </label>
                                 <select id="tscmSdrDevice" style="margin-top: 4px;">