Yeah, I don't know of any transmitters made today that use 10.8 volt packs, they're all 9.6 volt (8 cells).

Chances are that the radio you're father was using is no longer legal. It may not even be on a current legal frequency.

Let us know more. Manufacturer, number of channels, does it have a silver sticker on the back with a 1991 date? Post a picture of the transmitter if possible.

Sorry,
Dennis-