The Fuchs B25 manpack transceiver has an Antenna Tuning Unit (ATU) designed to match a short whip antenna, or feed a wire antenna. While I haven't measured the impedance tuning range of the ATU, it seems to be able to tune most loads I have connected to the transceiver. The ATU's utility is quite useful for my portable ham radio operations so I'd like to keep it in service.
I don't have a complete B25 kit, so I have to rely on images and make assumptions. I assume the whip antenna is fastened to the ATU via the screw thread. The wire antenna end seems to be inserted into a port adjacent to the thread. A thumbscrew is used to clamp down the antenna end against a conductive portion of the assembly.
I'm a big fan of 4mm banana connectors (except the plugs with the rotation sleeve!) and use short leads terminated with banana plugs with an End Fed Half Wave (EFHW) transformer. It would be luxurious to have a banana socket on the ATU via some sort of adapter.
Since my father is pretty handy on the lathe, he was able to turn up a brass adapter within a quick amount of time.
Initially thought to be M10 x 1.5, but by measuring dimensions and using a thread gauge, it was determined that the whip antenna thread was 3/8"-16 UNC. Fortunately my father's lathe was well suited to cutting this thread since the lead screw has a pitch of 8 Threads Per Inch (TPI) and so related by an integer.
3/8"-16 seems somewhat rare as an antenna thread. 3/8"-24 seems common, also 5/16"-24. This website reckons the PRC-47 uses a 3/8"-16 thread.
Here are some images of the adapter.
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