[Elecraft] K3 Question

[Ken K3IU]

Hi all:
I have searched the FAQs and the email archives for info about the 
connector on the back of the K3 marked "AUX RF" between the "ANT2" and 
the "12VDC IN" connections. Nothing was found when searching for "AUX 
RF." Has anyone out there come across what that is for? I notice that on 
the images of the back of a real live K3 that hole is not filled.

Thanks...
73, Ken K3IU
K3 on order