Index: sys/dev/usb/wlan/if_urtwn.c
===================================================================
--- sys/dev/usb/wlan/if_urtwn.c
+++ sys/dev/usb/wlan/if_urtwn.c
@@ -723,6 +723,7 @@
 			tap->wr_rate = 0x80 | (rate - 12);
 		}
 		tap->wr_dbm_antsignal = rssi;
+		tap->wr_dbm_antnoise = URTWN_NOISE_FLOOR;
 	}
 
 	*rssi_p = rssi;
Index: sys/dev/usb/wlan/if_urtwnvar.h
===================================================================
--- sys/dev/usb/wlan/if_urtwnvar.h
+++ sys/dev/usb/wlan/if_urtwnvar.h
@@ -40,7 +40,8 @@
 	uint8_t		wr_rate;
 	uint16_t	wr_chan_freq;
 	uint16_t	wr_chan_flags;
-	uint8_t		wr_dbm_antsignal;
+	int8_t		wr_dbm_antsignal;
+	int8_t		wr_dbm_antnoise;
 } __packed __aligned(8);
 
 #define URTWN_RX_RADIOTAP_PRESENT			\
@@ -48,7 +49,8 @@
 	 1 << IEEE80211_RADIOTAP_FLAGS |		\
 	 1 << IEEE80211_RADIOTAP_RATE |			\
 	 1 << IEEE80211_RADIOTAP_CHANNEL |		\
-	 1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL)
+	 1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL |	\
+	 1 << IEEE80211_RADIOTAP_DBM_ANTNOISE)
 
 struct urtwn_tx_radiotap_header {
 	struct ieee80211_radiotap_header wt_ihdr;