diff --git a/tools/atrf-txrx/atrf-txrx.c b/tools/atrf-txrx/atrf-txrx.c
index 7473758..64d6d25 100644
--- a/tools/atrf-txrx/atrf-txrx.c
+++ b/tools/atrf-txrx/atrf-txrx.c
@@ -184,7 +184,7 @@ static void receive_message(struct atrf_dsc *dsc)
 static void write_pcap_hdr(FILE *file)
 {
 	struct pcap_file_header hdr = {
-		.magic		= 0xa1b2c3d4,
+		.magic		= PCAP_FILE_MAGIC,
 		.version_major	= 2,
 		.version_minor	= 4,
 		.thiszone	= 0,
diff --git a/tools/atrf-txrx/pcap.h b/tools/atrf-txrx/pcap.h
index 8451472..beeac89 100644
--- a/tools/atrf-txrx/pcap.h
+++ b/tools/atrf-txrx/pcap.h
@@ -27,8 +27,11 @@
 #include <sys/time.h>
 
 
+#define	PCAP_FILE_MAGIC		0xa1b2c3d4
+
 #define	DLT_IEEE802_15_4	195
 
+
 struct pcap_file_header {
 	uint32_t magic;
 	uint16_t version_major;