Many thanks to Gordon (KF5JWL) who writes:
Tom,
I’ve been thinking about this for a while and finally tried it.
I attached an alligator clip to the AM-801 [window antenna mount] so it could be used to connect a counterpoise. Turns out alligator clips (at least the Mueller version I had lying around) have a toothy clip part at one end and a banana jack or socket at the other end. I didn’t want to go down the Google rabbit hole to find out if this is standard on all alligator clips. The clip also has a 6-32 threaded hole between the two ends so I drilled a clearance hole (using a #28 drill) in the AM-801 near the edge and attached the clip with a stubby 6-32 screw.
My trusty automatic center punch apparently failed to make a significant impression in the AM-801 so my drill bit wandered somewhat and the resulting hole was not exactly where I wanted it but I was still able to connect the alligator clip.
73,
Gordon KF5JWL
Thanks, Gordon! That’s a clever addition to the AM-801. Thank you for sharing it with us.