Trying to identify threaded round 2-way power connector on a radio
By the looks of it and the thread I'd say it's a 2-pin aviation connector (such as the one depicted here: https://www.ebay.com/itm/Hot-Sale-1-Set-GX16-2-Pin-Screw-Type-Electrical-Aviation-Plug-Socket-Connector/201465426325). However this one has one of the pins wider than the other (and the center notch is missing too), so this could be one of those lousy "proprietary" designs derived from the (more widely used) aviation connector design. You could give one of these aviation connectors a try and if it doesn't work out just unscrew the whole connector from behind and solder in something more standardized instead (perhaps even the said aviation connector).