Thank you to all who have replied. I have sent an email to Rainer, and am crossing my fingers. In the meantime I am :
1. ordering an external antenna, and
2. trying to fix the old antenna -
I found the original antenna and it seems to have the round tip broken off the small end section. Does anyone know whether I can just screw a self-tapping stainless steel screw into the opening in the broken section in order to perform the same function as the missing tip? If so, I may give that a try.