Just keep in mind that putting in the bridge rectifier or the set of diodes on the positive and negative leads will cause a 1.4V drop. So if you run 13.8V into the radio, the voltage after the diodes/rectifier will be 12.4V. You might not have 100% performance (output) out of the radio, but at least you can't hook it up wrong.
~Cheers~
~Cheers~