diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 949d5d6..3aed729 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1966,6 +1966,7 @@
 
 	if (ah->hw->conf.radar_enabled) {
 		/* set HW specific DFS configuration */
+		ah->radar_conf.ext_channel = IS_CHAN_HT40(chan);
 		ath9k_hw_set_radar_params(ah);
 	}