diff --git a/src/gsmtap_util.c b/src/gsmtap_util.c
index 9a0ac02..336e1d0 100644
--- a/src/gsmtap_util.c
+++ b/src/gsmtap_util.c
@@ -176,7 +176,7 @@
  */
 struct msgb *gsmtap_makemsg_ex(uint8_t type, uint16_t arfcn, uint8_t ts, uint8_t chan_type,
 			    uint8_t ss, uint32_t fn, int8_t signal_dbm,
-			    uint8_t snr, const uint8_t *data, unsigned int len)
+			    int8_t snr, const uint8_t *data, unsigned int len)
 {
 	struct msgb *msg;
 	struct gsmtap_hdr *gh;
@@ -223,7 +223,7 @@
  */
 struct msgb *gsmtap_makemsg(uint16_t arfcn, uint8_t ts, uint8_t chan_type,
 			    uint8_t ss, uint32_t fn, int8_t signal_dbm,
-			    uint8_t snr, const uint8_t *data, unsigned int len)
+			    int8_t snr, const uint8_t *data, unsigned int len)
 {
 	return gsmtap_makemsg_ex(GSMTAP_TYPE_UM, arfcn, ts, chan_type,
 		ss, fn, signal_dbm, snr, data, len);
@@ -326,7 +326,7 @@
  */
 int gsmtap_send_ex(struct gsmtap_inst *gti, uint8_t type, uint16_t arfcn, uint8_t ts,
 		uint8_t chan_type, uint8_t ss, uint32_t fn,
-		int8_t signal_dbm, uint8_t snr, const uint8_t *data,
+		int8_t signal_dbm, int8_t snr, const uint8_t *data,
 		unsigned int len)
 {
 	struct msgb *msg;
@@ -351,7 +351,7 @@
  */
 int gsmtap_send(struct gsmtap_inst *gti, uint16_t arfcn, uint8_t ts,
 		uint8_t chan_type, uint8_t ss, uint32_t fn,
-		int8_t signal_dbm, uint8_t snr, const uint8_t *data,
+		int8_t signal_dbm, int8_t snr, const uint8_t *data,
 		unsigned int len)
 {
 	return gsmtap_send_ex(gti, GSMTAP_TYPE_UM, arfcn, ts, chan_type, ss, fn,