I've had this thing laying around for years, I have no idea even where I got it from. I always thought it was something interesting so it never got tossed out. Like a lot of other stuff,

this is why I have a 2 car garage that's never had a car parked in it...

Anyway, I seem to remember seeing a photo on the web somewhere of a Signal Corps portable radio with antenna mount on the side of the cabinet and it had one of these as the antenna mount.

Does anyone know what this is?

I don't really have a use for it so if someone can use it and has something interesting to trade, let me know.