Somewhere in my garage I might still have the AEA board that plugs into the game port. I used this with a VIC20, but it should probably work with the 64. I also have an AEA CP-1 unit to go along with the board. Documentation? Good luck with that!
That's AWESOME! I would be willing to bet that MANY hams have fully capable "computers" (a.k.a. C64/VIC20) in their possession...complete with the "software and hardware" for them!
In the late 1980's as a new Novice, the COOLEST program cartridge I ever saw for Commodore was the Dr. QSO (I think that was the name). I seem to remember that it had a "virtual QSO" mode. I remember having a CW "QSO" with the robot. Very cool. Wish I had THAT today!