I've got a problem where when I select the 73 (don't remember whether it's the long or short) right after the tx begins a bunch of

?? get inserted into the macro right after the call , Thought at first that some stray RF was getting into the USB between the computer and signal link but why just the 73? Nothing else, even when I have a long type rag chew. Should I insert a bead on the USB cable??