diff --git a/main/traffic.go b/main/traffic.go
index bf551416..9689bdb5 100644
--- a/main/traffic.go
+++ b/main/traffic.go
@@ -269,7 +269,7 @@ func parseDownlinkReport(s string) {
 		if ns_vel_valid && ew_vel_valid {
 			if ns_vel != 0 && ew_vel != 0 {
 				//TODO: Track type
-				track = (360 + 90 - (uint16(math.Atan2(float64(ns_vel), float64(ew_vel)) * 180 / math.Pi))) % 360
+				track = uint16((360 + 90 - (int16(math.Atan2(float64(ns_vel), float64(ew_vel)) * 180 / math.Pi))) % 360)
 			}
 			speed_valid = true
 			speed = uint16(math.Sqrt(float64((ns_vel * ns_vel) + (ew_vel * ew_vel))))