I finally got an opportunity to confirm that my recently installed Raymarine Ray49 DSC-enabled, two-way-NMEA, VHF radio is working correctly. For those just joining us, you can read about my first impressions of the radio itself and my crazy NMEA wiring scheme.

Anyway, once I got it all hooked up a few weeks ago, everything appeared to be working fine. Everything, that is, except NMEA data from the VHF to my Raymarine C-80. This sort of data is pretty infrequent, so I was not able to test that it was working until yesterday. I got some help from Captain Mac Lamay aboard Island Ranger. I sent DSC position requests to Island Ranger to conduct this test.

And it works! When the Ray49 VHF radio receives a vessel position message over DSC, it forwards it (via the AIS) to the chartplotter, which displays a dialogue like this:

At this point, you've got three options: place a waypoint, begin navigating toward the coordinates, or clear the message and ignore it.

If I were to see this dialogue box associated with a distress call, here's what I would do:

I would hit the "Goto Vessel" softkey, and then slow down and listen to the radio for additional information. If I decide that my participation could potentially benefit the outcome, my nav system is already set up to help me get there. If not, I can just "Stop Goto" and proceed on my way.

By the way, I was interested to see just what these DSC NMEA "sentences" look like. There are two associated with each position report, and they begin with CDDSC and CDDSE, respectively. The rest of the messages you see in the buffer are AIS messages.

So after all this, it all really, really works, for which I'm heartily grateful!