I've bought a West Marine (Uniden) VHF580 marine radio for my boat because I didn't have the money for one with built in GPS. Its a DSC radio with GPS capabilities. I've learned that I can add a GPS antenna to it by connecting a simple GPS puck.

Essentially, its signal wire in, signal wire out, and two power wires. Problem is that my boat is a 12v source, an the GPS pucks are typically 5v.

This guy has a nifty little solution he shows here, but doesn't detail any of the wiring - http://theensign.org/connect-gps-vhf-radio/ and I know its not as simple as just buying that box.

Any ideas on how he wired this up? Or any suggestions for the easiest way to get this done?