Portable radio specialists SOTABEAMS has introduced a useful patch lead designed to complement the new LNR Mountain Topper radio. The lead has an RCA plug on one end and a BNC plug on the other. This removes the need to use adapters which might otherwise strain the radio connector. The lead is made with RG174 and both connectors are sealed onto the wire for better water resistance. SOTABEAMS ships worldwide from their UK HQ.
Thing like that would take 5 mins to make, let alone pay freight costs on top as well. Thought radio hams were supposed to be technically capable.
Look at Universal - Radio under RCA adapters -There are many choices of adapters- So238, BNC, etc. 73