diff --git a/Moose Development/Moose/Core/RadioQueue.lua b/Moose Development/Moose/Core/RadioQueue.lua
index 756b5a967..2166c54fa 100644
--- a/Moose Development/Moose/Core/RadioQueue.lua	
+++ b/Moose Development/Moose/Core/RadioQueue.lua	
@@ -279,6 +279,10 @@ end
 -- @return #number Duration of the call in seconds.
 function RADIOQUEUE:Number2Transmission(number, delay, interval)
 
+  if not number then
+    self:E("ERROR: Number is nil!")
+  end
+
   --- Split string into characters.
   local function _split(str)
     local chars={}