Safety Step: NMEA, GPS, DSC Oh My!

After I had all of the components for connecting the marine electronics together, I got right to it!  Truthfully, it was pretty simple.  The previous owners of Journey had installed all new electronics in 2009 and everything would either talk or listen using the standard NMEA 0183  protocol or Seatalk, Raymarine’s proprietary version.  That means that all of the components had a set of wires ready to be connected to everything else so they could communicate.  On the first work day, I connected all of the Raymarine equipment that was not already wired together and most of the functionality was there, except the GPS was not communicating with anything.  I was concerned about this because there is a lot to be gained from having the GPS be a talker.  Mainly I wanted to be able to use the DSC feature of the VHF radio.  DSC stands for Digital Selective Calling and I have recently learned that it can do a bunch of cool things, but most importantly it can communicate a distress signal, including the vessel’s position, to any receiving station within listening distance at the push of a button.  This eliminates the need for someone to verbally make contact with say, the Coast Guard.  Instead, a digital signal is sent out repeatedly until a response is sent back to the vessel.  It’s a safety thing!

For minimal expense, only the cost of the cable and connectors, the VHF is now receiving the signal from the GPS and shows our GPS coordinates right on the display.  I was surprised that this was not originally connected by the previous owner, but I have since found that he had concerns of losing all electronics at once by a chain reaction if they were all connected and one of them were to short out.  I agree that it’s a valid concern, but I am going to hope that never happens and now have the additional safety benefit of the push button distress call.  To each his own!

So now everything is talking and listening and we have much more functionality.  We can insert waypoints into the GPS and tell the autopilot to steer the way!  Not that we are going to take our watch duties less serious, just that we do not have to let the beautiful scenery pass us by on the way!

Our VHF Radio showing our current coordinates.

Our VHF Radio showing data received from GPS!

I have also been considering what other electrical components I feel we need for our trip, mainly for communications.  I have been debating on AIS, an SSB transceiver, and a wi-fi antenna.  So far I have not reached a real decision on any of them, but I am starting to think I will pass on AIS.  I think that the receiver-only units are priced somewhat affordable, but the real benefit of AIS would be realized if the big ships could see us, meaning we would need one of the much more expensive transponder units.  Since AIS receiver info is also available via internet when we have cellular signal, it just isn’t worth parting with the funds that could go to something else.  I am also leaning away from an SSB transceiver too.  For our cruising plans, I do not think that the high cost is justified when we will usually be within range of another boat or port that can be reached with the VHF radio.  I go back and forth on it though since I know that it is another safety device and I could easily recoup much of the cost later if I sold it.  For now though, I am seriously considering getting a wi-fi antenna.  Not just because it is much less expensive than the other electronics I just talked about, but also because most of the time we can’t even pick up the marina wi-fi when we are in our slip!  It sure would be nice to be able to post this from the dock!


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