diff --git a/web/chat.html b/web/chat.html
index a6e9313..5e40332 100644
--- a/web/chat.html
+++ b/web/chat.html
@@ -772,6 +772,15 @@ async function onRxFrame(bytes) {
     logLine('err', `rx: malformed frame (type=${f.type}, ${f.error})`);
     return;
   }
+  /* same-machine PA mix echoes our own carrier back to us. drop any frame
+   * whose sender id matches our own so we don't double-render. loopback
+   * mode is unaffected because BroadcastChannel never echoes to sender.   */
+  if (f.sid) {
+    const mine = await senderIdBytes();
+    let isSelf = true;
+    for (let i = 0; i < 4; i++) if (f.sid[i] !== mine[i]) { isSelf = false; break; }
+    if (isSelf) return;
+  }
   if (f.type === T_OFFER) {
     logLine('sys', `rx: OFFER from peer — ${f.baud} baud`);
     /* respond with READY at handshake baud */