diff --git a/src/main/java/altk/comm/engine/Broadcast.java b/src/main/java/altk/comm/engine/Broadcast.java
index 61a692e..76481db 100644
--- a/src/main/java/altk/comm/engine/Broadcast.java
+++ b/src/main/java/altk/comm/engine/Broadcast.java
@@ -1112,7 +1112,9 @@ public abstract class Broadcast
     }
 	
 	private boolean withinOperatingHours() {
+		if (daily_start == null || daily_start.trim().length() == 0) return true;
 		int dailyStartMin = convert2Min(daily_start);
+		if (daily_stop == null || daily_stop.trim().length() == 0) return true;
 		int dailyStopMin = convert2Min(daily_stop);
 		// Ensure daily stop > daily start
 		if (dailyStopMin < dailyStartMin) dailyStopMin += 24 * 60;
@@ -1458,10 +1460,8 @@ public abstract class Broadcast
 		boolean timeChanged = false;
 		for (String key : new String[] {DAILY_STOP_KEY, DAILY_START_KEY}) {
 			String value = (String)configuration.get(key);
-			if (value != null) {
-				if (setOperatingHours(key, value)) {
-					timeChanged = true;
-				}
+			if (setOperatingHours(key, value)) {
+				timeChanged = true;
 			}
 		}
 		if (timeChanged) enforceOperationHours();