diff --git a/firmware/inc/ax25.h b/firmware/inc/ax25.h
index 15a2153..e6b1c44 100644
--- a/firmware/inc/ax25.h
+++ b/firmware/inc/ax25.h
@@ -48,7 +48,7 @@
  * AX25 packet parameters
  */
 #define AX25_BITSTUFFINGCOUNT	5
-#define AX25_PREAMBLE_FLAGS	15 /* 100 ms of flags */
+#define AX25_PREAMBLE_FLAGS	30 /* 200 ms of flags (normally 100ms?) */
 #define AX25_POSTAMBLE_FLAGS	1
 #define AX25_MAX_FRAME_LEN	0x100