Connecting a Handheld GPS to a Marine VHF Radio

Explains how a connected a low cost handheld GPS to a low cost (on sale) VHF marine radio. This supports DSC (digital selective calling) and automated distress calls.

(I'll upload some photos of this tonight)

The VHF radio - I picked this up new, at a really good price due to a sale. In the process I also learned that it can be connected to a GPS and learned how the automated distress signal works. I also learned that with DSC it can send position info to other boats.
(note: at the time of purchase, I didn't know it could work with my handheld GPS)
The ETrex GPS - really cheap haldheld unit that has served well over the last couple of years.
DB9 Serial Connector - from an old computer. You should be able to find this at your local electronics shack.

The manual for the radio states that accessories need to implement the NMEA 0183 standard (I later learned what this is).
A google search for NMEA and ETrex shows a site listing GPS units that support the standard. Mine is listed, woohoo.
I later discovered that in the setup menu in the GPS, its a communication option (I should have checked the device first).

I hooked up the serial interface cable to the GPS, next, I googled for the pin diagram.
It shows serial communication from pin 2 or 3 and the ground on pin 5.
I fire up the radio and the GPS.
I just stick the bare ground in the number 5 hole in the serial connector, and the other wire in the pin 2, nothing happens. Move it to pin three, a few seconds later, life. Woohoo.