This is starting to make sense to me. I don't think I've ever seen a serial cable that delivered data and also power. There are however USB cables that deliver data and power.
That being said, I think you are right that you will have to get the other cable so that you can deliver the power and data. Or just connect power and data separately.
@nokones expressed it well. After hurricane Beryl, the only coms I had for a few days was GMRS and ham radio which worked very well. But that was NOT an SHFT situation and there were repeaters that were still available. Under a real SHFT, radios may not be as useful as we would like.
@WSFP385 just an added note, some radios actually perform better with the stock antenna. Sometimes the stock antenna is well designed and is tuned to that specific radio and is hard to beat. I don't know if your radio is one of those.