Connecting VHF Radio to Sonar

[Ringo]

I am going to install a new VHF radio on my boat which comes with the built-in GPS tracking function and antenna for the DSC callings (ICOM-M330G). I already have a Garmin 942Xs which can be connected to a VHF radio through a NMEA connection. The shop that sold me the VHF didn't see any benefits in connecting the two devices but I'm not 100% sold on that.

I don't have a radar and am not planning to add one in the future so this is going to be mainly for basic VHF functions.

What are the benefits of setting up a NMEA network and have the two devices synced-up? Is ICOM's GPS receiving function as accurate and reliable as the Garmin chartplotter? I'm all for keeping it as simple as possible but I'm also new to the NMEA networking world and can use any advice from the forum members.

 

[Baxter]

First, you need to link the two for your emergency button on the VHF to work (although, perhaps some VHF have built in GPS as well? not sure). That is the only reason I linked mine. I want to be able to flip that switch and jump overboard when my boat is on fire.


But if you want to use AIS I think you need to link them as well. I believe when linked you can also get info from those calling in with distress signals to have data appear on your sounder etc.

In my case, it was as simple as matching up some wires on the sounder with those on the vhf. Once I knew what wires were what it was a quick connection. I think I had to turn on a setting as well, but can't recall for sure, it was a while ago.

 

[Matt16]

New DSC radios usually have their own GPS chips nowadays.

I have a Garmin 942xs and was going to try to hook the chartplotter up to my older West Marine radio (no GPS). Spoke with Garmin and West Marine's electronics specialist, didn't get anywhere. All the manufacturers use different protocols for colour coding wires.

Long story short, I just boat a new DSC radio with a GPS chip inside and called it good. Even if the 942xs has a better GPS chip, I don't see a benefit to being 5 m more accurate. If the Coast Guard gets within a few hundred meters, our DSC has done its job. Its probably accurate to within a few meter anyways. From a reliability standpoint, the integrated DSC GPS radio seems safer.

 

[BryceWCP]

The icom 330g has the external gps receiver. All you need to do to access the DSC functions is enter your mmsi number. Easy to get if you don’t have one already. The 330g does not have NMEA2000 connect ability so you can’t link it to your chart plotter.

 

[Enniberg]

The icom 330g has the external gps receiver. All you need to do to access the DSC functions is enter your mmsi number. Easy to get if you don’t have one already. The 330g does not have NMEA2000 connect ability so you can’t link it to your chart plotter.

I have been wondering about that - does NMEA 0183 not suffice for transferring AIS data from the radio to the chart plotter?

 

[BryceWCP]

I have been wondering about that - does NMEA 0183 not suffice for transferring AIS data from the radio to the chart plotter?

The 330g is not AIS compatible. The icom M506 has both AIS and NMEA2000 connections.

 

[Enniberg]

The 330g is not AIS compatible. The icom M506 has both AIS and NMEA2000 connections.

In my case I have a radio that does have GPS and AIS - is NMEA 0183 sufficient in that case for displaying AIS on my Garmin 942xs?

 

[BryceWCP]

In my case I have a radio that does have GPS and AIS - is NMEA 0183 sufficient in that case for displaying AIS on my Garmin 942xs?

That I’m not sure. You could have to refer to your install manual

 

[Ringo]

Does the NMEA0183 send the vessel’s location for the incoming DSC calls to the chartplotter? Can I even get that data on M330G without AIS?

 

[sly_karma]

Does the NMEA0183 send the vessel’s location for the incoming DSC calls to the chartplotter? Can I even get that data on M330G without AIS?

As I understand it, yes. Did this some years back with VHF-GPS link. Connected the Lowrance wiring with 24 AWG butt splice connectors and instantly had lat and long data appear on VHF display. No AIS function on this VHF set.