If I remember they were affordable at the time. Looking on ebay now, they are costing about $135 shipped to the US, and that sounds about right for what I am remembering.
Look at this one https://www.ebay.com/itm/Military-VHF-Radio-RU-2/283423457872?hash=item41fd5ac250:g:gssAAOSwfiZckTGj
Here in the States we have a discount tool store known as Harbor Freight. It is an emporium of their own branded inexpensive Chinese tools. Harbor Freight is always upgrading the type of cordless drills they are selling, and almost always they have a 9v, 12v or 18v NiCad discontinued battery pack on sale. While not "top of the line" in amp hours as after market NiCad, and no where near as efficient as Julian's OH8STN LiPo packs(!), they are inexpensive to disassemble, make into a custom voltage pack, light weight, and easy to charge with a dedicated NiCd charger, or generic bench power supply in constant current mode.
You can make a pack of cells up with just standard hook up wire of the correct gauge, easy solder tabs and wrap the whole thing in a roll of inexpensive electrical tape (from Harbor Freight for 69 ¢!) and you have a battery pack!. I will get some more pictures this weekend, as I need to take it out of the RUP-12 and recharge it, and test some more voltages and current draw!