diff --git a/wo-bisch-lorahandler.go b/wo-bisch-lorahandler.go
index 24c2981..fc7416a 100644
--- a/wo-bisch-lorahandler.go
+++ b/wo-bisch-lorahandler.go
@@ -67,14 +67,15 @@ func Convert2Hex(payload_raw string) (string, error) {
 	return res, err
 }
 
-func IsOutsideGreenzone(deveui string, lon float64, lat float64) bool {
-	res := false
+// 0: inside greenzone, 1: outside greenzone, 2: no GPS
+func IsOutsideGreenzone(deveui string, lon float64, lat float64) int {
 	if lon < 1 {
-		return res
+		return 2
 	}
 	if lat < 1 {
-		return res
+		return 2
 	}
+	res := false
 	greenzone := getDevGreenzone(deveui)
 	if greenzone != "" {
 		coords := strings.Split(greenzone, ",")
@@ -88,7 +89,11 @@ func IsOutsideGreenzone(deveui string, lon float64, lat float64) bool {
 			log.Printf("greenzone does not have right format: %s!", greenzone)
 		}
 	}
-	return res
+	if res {
+		return 1
+	} else {
+		return 0
+	}
 }
 
 func DecodePayload(s string, deveui string) {
@@ -121,7 +126,7 @@ func DecodePayload(s string, deveui string) {
 		alarm := (pl.AlarmBat & 0x4000) == 0x4000 // Alarm Bit
 		outsideGreenzone := IsOutsideGreenzone(deveui, float64(pl.Longitude)/1000000.0, float64(pl.Latitude)/1000000.0)
 		flags := 0
-		if outsideGreenzone {
+		if outsideGreenzone == 1 {
 			flags += 2
 		}
 		if alarm {
@@ -129,7 +134,7 @@ func DecodePayload(s string, deveui string) {
 		}
 
 		log.Printf("AlarmBit:         %v", alarm)
-		log.Printf("outsideGreenzone: %v", outsideGreenzone)
+		log.Printf("outsideGreenzone: %d", outsideGreenzone)
 
 		mystring := fmt.Sprintf("measurement,deveui=%s lat=%.5f,lon=%.5f,vbat=%d,fw=%d,flags=%d %d\n", deveui, float32(pl.Latitude)/1000000.0, float32(pl.Longitude)/1000000.0, vbat, fw, flags, (time.Now().Unix() * 1000 * 1000 * 1000))
 
@@ -139,10 +144,10 @@ func DecodePayload(s string, deveui string) {
 			log.Printf("DispatchAlert (button pressed) for %s\n", deveui)
 			DispatchAlert(deveui, "alert_button")
 		}
-		if outsideGreenzone {
+		if outsideGreenzone == 1 {
 			log.Printf("DispatchAlert (outside greenzone) for %s\n", deveui)
 			DispatchAlert(deveui, "alert_greenzone")
-		} else {
+		} else if outsideGreenzone == 0 {
 			// we reset the alert, when we are again withing the greenzone
 			if AlertAlreadySentRecently(deveui, "alert_greenzone") {
 				fmt.Printf("Info: we are again in Greenzone for Deveui %s, clear alert!", deveui)