Connecting Chartplotter to VHF

[Joe500]

I am trying to connect a Magellan Nav 6500 chartplotter to a new Icom 504 VHF radio. I have a few questions:

1)On the Icom radio, the NMEA input is one wire with the inner part being NMEA+ and the outer shield labelled NMEA-. How do I connect two normal wires to this? Is there some kind of adaptor? Or do I just try to roll back the shield and twist it into a wire?

2)The Magellan chartplotter has an NMEA+ output but no NMEA- output. The Magellan manual advises just connecting NMEA- to the black wire which also is the 12V negative wire. Can I just connect the VHF's NMEA input (-) to the negative terminal on the breaker panel (would actually be a different subpanel) rather than connecting it to the Magellan's black wire? That seems equivalent.

I'm worried about breaking my expensive new radio and so wanted to make sure I was doing this correctly.

[fairbank56]

Yes, you could do it that way, connecting negative to the shield of the nmea input on your VHF if there's some reason for not coming off the chartplotter wiring. The M-504 has an isolated nmea input through an opto-isolator. There is no electrical connection to anything else inside the radio including ground except for a couple of bypass capacitors.

Eric