diff --git a/src/main.cpp b/src/main.cpp
index a8282de..273b420 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -175,9 +175,12 @@ static volatile bool      capBufFull  = false;  // set by ISR when buffer fills
 static          uint32_t  capRecBits  = 0;      // bits stored after recording
 static          float     capFreq     = 315.0f; // frequency at capture time
 static          uint8_t   capRadioNum = 1;      // 1 or 2
+static          bool      capIsOOK    = true;   // modulation: true=OOK, false=2-FSK
 static          gpio_num_t capGdoPin  = (gpio_num_t)CC1101_1_GDO0;
 static          hw_timer_t* capTimer      = nullptr;
-static volatile uint32_t   capTransitions = 0;    // edge count — used to detect live signal
+static volatile uint32_t   capTransitions = 0;    // edge count — used for bitrate estimation
+static volatile uint32_t   capLongRuns    = 0;    // counts stable runs (>15 samples) to filter out thermal noise
+static          uint32_t   capCurrentRun  = 0;    // current stable run length
 static          bool        capSigNotified = false; // fire OLED notification only once per session
 static          bool        capPrevJamming = false; // jammingEnabled state saved before capture pauses it
 
@@ -186,10 +189,16 @@ static void IRAM_ATTR capRecordISR() {
   const uint32_t i = capIdx;
   if (i >= (uint32_t)(CAP_BUF_BYTES * 8)) { capBufFull = true; return; }
   const uint8_t bit = (uint8_t)((REG_READ(GPIO_IN_REG) >> capGdoPin) & 1u);
-  // Count transitions — cheap edge detection without extra storage
+  // Count transitions and long stable runs (software squelch)
   if (i > 0) {
     const uint8_t prev = (capBuf[(i-1) >> 3] >> ((i-1) & 7)) & 1u;
-    if (bit != prev) capTransitions++;
+    if (bit == prev) {
+      capCurrentRun++;
+    } else {
+      capTransitions++;
+      if (capCurrentRun > 15) capLongRuns++;
+      capCurrentRun = 0;
+    }
   }
   if (bit) capBuf[i >> 3] |=  (1u << (i & 7));
   else     capBuf[i >> 3] &= ~(1u << (i & 7));
@@ -214,22 +223,26 @@ static void capTimerStop() {
   }
 }
 
-static void startCapture(float freq, uint8_t radioNum) {
+static void startCapture(float freq, uint8_t radioNum, bool isOOK) {
   capPrevJamming = jammingEnabled;  // save before stopJamming() clears it
   stopJamming();
 
   capFreq     = freq;
   capRadioNum = radioNum;
+  capIsOOK    = isOOK;
   capGdoPin   = (radioNum == 1) ? (gpio_num_t)CC1101_1_GDO0 : (gpio_num_t)CC1101_2_GDO0;
   capIdx         = 0;
   capBufFull     = false;
   capRecBits     = 0;
   capTransitions = 0;
+  capLongRuns    = 0;
+  capCurrentRun  = 0;
   capSigNotified = false;
   memset(capBuf, 0, sizeof(capBuf));
 
   CC1101& radio = (radioNum == 1) ? radio1 : radio2;
   radio.standby();
+  radio.setOOK(isOOK);
   radio.setFrequency(freq);
   radio.setFrequencyDeviation(JAM_FREQ_DEV_KHZ);
   radio.receiveDirect();  // GDO0 becomes demodulated-data output from CC1101
@@ -261,6 +274,7 @@ static void startReplay(uint8_t radioNum) {
 
   CC1101& radio = (radioNum == 1) ? radio1 : radio2;
   radio.standby();
+  radio.setOOK(capIsOOK);
   radio.setFrequency(capFreq);
   radio.setFrequencyDeviation(JAM_FREQ_DEV_KHZ);
   radio.transmitDirectAsync();  // GDO0 becomes data input to CC1101
@@ -296,6 +310,7 @@ static void stopCapture() {
   gpio_set_direction(capGdoPin, GPIO_MODE_OUTPUT);
   gpio_set_level(capGdoPin, 0);
   if (capPrevJamming) {
+    capPrevJamming = false;
     jammingEnabled = true;
     startJamming();
   }
@@ -739,8 +754,10 @@ static void oledTick() {
 
   // Consume encoder — manual page change resets the auto-cycle timer
   if (encDelta != 0) {
+    noInterrupts();
     const int8_t d = encDelta;
     encDelta = 0;
+    interrupts();
     oledPage = (uint8_t)((oledPage + 3 + (d > 0 ? 1 : -1)) % 3);
     oledPageMs = now;   // reset auto-advance so page stays visible
   }
@@ -1024,6 +1041,13 @@ pre{margin:0;padding:8px;background:#020504;border:1px solid #122814;height:28vh
       <label>Target Frequency (MHz)</label>
       <input type="number" id="capFreq" min="290" max="450" step="0.001" value="315.000" style="width:110px">
     </div>
+    <div class="col">
+      <label>Modulation</label>
+      <select id="capMod" style="background:#020504;border:1px solid #1a3a1e;color:#86f28a;padding:3px 6px;font-family:inherit;font-size:11px">
+        <option value="ook">OOK / ASK (90% of fobs)</option>
+        <option value="fsk">2-FSK</option>
+      </select>
+    </div>
     <div class="col">
       <label>Radio</label>
       <select id="capRadio" style="background:#020504;border:1px solid #1a3a1e;color:#86f28a;padding:3px 6px;font-family:inherit;font-size:11px">
@@ -1260,8 +1284,9 @@ async function capFetch(url){try{return await(await fetch(url)).json();}catch(e)
 async function capStartRec(){
   const freq=+document.getElementById('capFreq').value;
   const radio=+document.getElementById('capRadio').value;
+  const mod=document.getElementById('capMod').value;
   if(isNaN(freq)||freq<290||freq>450){alert('Frequency must be 290-450 MHz');return;}
-  const d=await capFetch('/api/capture/start?freq='+freq+'&radio='+radio);
+  const d=await capFetch('/api/capture/start?freq='+freq+'&radio='+radio+'&mod='+mod);
   if(d){capSetStatus('RECORDING',d);capPollStart();}
 }
 
@@ -1520,7 +1545,8 @@ static void handleHealth() {
 static void handleCaptureStart() {
   const float  freq  = server.hasArg("freq")  ? server.arg("freq").toFloat()  : 315.0f;
   const uint8_t radio = server.hasArg("radio") ? (uint8_t)server.arg("radio").toInt() : 1;
-  startCapture(freq, radio);
+  const bool   isOOK = server.hasArg("mod") ? (server.arg("mod") == "ook") : true;
+  startCapture(freq, radio, isOOK);
   server.send(200, "application/json", "{\"status\":\"recording\",\"freq\":" +
               String(freq, 3) + ",\"duration_ms\":" + String(CAP_DURATION_S * 1000) + "}");
 }
@@ -1533,6 +1559,7 @@ static void handleCaptureStop() {
 
 static void handleCaptureReplay() {
   const uint8_t radio = server.hasArg("radio") ? (uint8_t)server.arg("radio").toInt() : 1;
+  // startReplay doesn't need isOOK from UI because it uses capIsOOK saved during capture
   startReplay(radio);
   server.send(200, "application/json", "{\"status\":\"replaying\",\"bits\":" +
               String(capRecBits) + ",\"freq\":" + String(capFreq, 3) + "}");
@@ -1796,12 +1823,12 @@ void loop() {
   // Capture state machine — runs in main loop (ISR sets flags, loop acts on them)
 
   // Signal-present detection: fire OLED "SIGNAL!" once per session when
-  // the ISR has seen enough transitions to indicate a real RF burst.
-  // 80 transitions ≈ a few milliseconds of OOK/FSK activity at any typical fob rate.
-  if (capMode == CapMode::RECORDING && !capSigNotified && capTransitions > 80) {
+  // the ISR has seen enough stable bits to indicate a real RF burst.
+  // capLongRuns > 10 filters out thermal noise which transitions almost constantly.
+  if (capMode == CapMode::RECORDING && !capSigNotified && capLongRuns > 10) {
     capSigNotified = true;
     oledNotify("SIGNAL!", "CAUGHT -- PRESS STOP", 3000);
-    logLine("[CAP] Signal detected: " + String(capTransitions) + " transitions @ bit " + String(capIdx));
+    logLine("[CAP] Signal detected: " + String(capLongRuns) + " valid symbols @ bit " + String(capIdx));
   }
 
   if (capMode == CapMode::RECORDING && capBufFull) {
@@ -1814,7 +1841,11 @@ void loop() {
     logLine("[CAP] Buffer full: " + String(capRecBits) + " bits (" +
             String(capRecBits * 1000 / CAP_SAMPLE_HZ) + " ms) captured");
     oledNotify("CAPTURED", (String(capRecBits * 1000 / CAP_SAMPLE_HZ) + "ms").c_str());
-    if (capPrevJamming) { jammingEnabled = true; startJamming(); }
+    if (capPrevJamming) { 
+      capPrevJamming = false;
+      jammingEnabled = true; 
+      startJamming(); 
+    }
   }
 
   // Auto-reinit watchdog: if jamming should be active but a radio failed, retry every 30s