diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index b7b1ad2..6332de6 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -146,7 +146,7 @@ Discovery pings use the MeshCore control data protocol to directly query nearby
 
 Three auto-ping modes are available after connecting:
 
-- **Active Mode**: Sends TX pings at user-configured interval (15s, 30s, or 60s). Each ping broadcasts a group channel message containing GPS location and radio power to `#wardriving`, then listens 7s for repeater echoes via `TxTracker`.
+- **Active Mode**: Sends TX pings at user-configured interval (15s, 30s, or 60s). Each ping broadcasts a 3-byte UID (derived from coordinates + timestamp) to `#wardriving`, then listens 7s for repeater echoes via `TxTracker`. Coordinates and power are sent in the API payload only.
 - **Passive Mode**: Sends discovery requests every 30s. No TX pings — only discovery request-response. Responses tracked via `DiscTracker`.
 - **Hybrid Mode**: Alternates between discovery and TX pings at the user-configured interval. Discovery → TX → Discovery → TX...
 
diff --git a/lib/services/meshcore/connection.dart b/lib/services/meshcore/connection.dart
index 66bc30c..9e3a7ba 100644
--- a/lib/services/meshcore/connection.dart
+++ b/lib/services/meshcore/connection.dart
@@ -967,19 +967,14 @@ class MeshCoreConnection {
   }
 
   /// Send ping to #wardriving channel
-  /// Format: @[MapperBot] LAT, LON
-  /// Power is no longer included in the mesh message — it is sent per-ping in the API payload instead
-  /// Reference: buildPayload() in wardrive.js
-  Future<void> sendPing(double lat, double lon) async {
+  /// Coordinates and power are no longer included in the mesh message — sent per-ping in API payload instead
+  /// Message is a 3-byte UID (6 hex chars) derived from coordinates + timestamp
+  Future<void> sendPing(String message) async {
     final channel = _wardrivingChannel;
     if (channel == null) {
       throw Exception('Wardriving channel not initialized');
     }
 
-    // Format coordinates to 5 decimal places with comma separator
-    final coordsStr = '${lat.toStringAsFixed(5)}, ${lon.toStringAsFixed(5)}';
-    final message = '@[MapperBot] $coordsStr';
-
     debugLog('[CONN] Sending ping: $message');
     final timestamp = DateTime.now().millisecondsSinceEpoch ~/ 1000;
     await sendChannelTextMessage(TxtTypes.plain, channel.channelIndex, timestamp, message);
diff --git a/lib/services/ping_service.dart b/lib/services/ping_service.dart
index 50bc46e..2187e7d 100644
--- a/lib/services/ping_service.dart
+++ b/lib/services/ping_service.dart
@@ -554,10 +554,11 @@ class PingService {
       }
       final txPowerDbm = _connection.deviceModel?.txPower ?? 22;
 
-      // Build ping message (same format used for TxTracker correlation)
-      // Power is no longer included in the mesh message — sent per-ping in API payload
-      final coordsStr = '${position.latitude.toStringAsFixed(5)}, ${position.longitude.toStringAsFixed(5)}';
-      final pingMessage = '@[MapperBot] $coordsStr';
+      // Build 3-byte ping UID from coordinates + timestamp (for TxTracker correlation)
+      // Coordinates and power are no longer included in the mesh message — sent per-ping in API payload
+      final hash = '${position.latitude},${position.longitude},${DateTime.now().millisecondsSinceEpoch ~/ 1000}'.hashCode;
+      final pingMessage = (hash & 0xFFFFFF).toRadixString(16).padLeft(6, '0');
+      debugLog('[PING] Generated UID: $pingMessage');
 
       // Capture noise floor at ping time
       final noiseFloor = _connection.lastNoiseFloor;
@@ -638,8 +639,8 @@ class PingService {
       // Play transmit sound immediately before sending
       _audioService?.playTransmitSound();
 
-      // Send ping via BLE (coordinates only — power is in API payload)
-      await _connection.sendPing(position.latitude, position.longitude);
+      // Send ping via BLE (UID only — coordinates and power are in API payload)
+      await _connection.sendPing(pingMessage);
 
       // Mark ping time and position
       _lastTxTime = DateTime.now();