VHF NEMA connection for making DSC calls using AIS

[Pat T]

Thanks to many TF folks I have been able to install 2 new VHF radios and antennas along with 2 new Raymarine Axiom MFD's. Just needed a little boatyard help with the VHF antennas otherwise all the other work completed by me.
To complete the job I would like to be able to use the VHF in conjunction with the AIS to make DSC calls. Therefore I have to connect the NEMA 0183 from the VHF's to the Raymarine backbone (if I am correct).

There is an open yellow plug on the backbone where I am guessing is a Raymarine converter. If I have it right this is where the VHF NEMA would be connected. But in looking at the cable that would be spliced to the NEMA connection on the VHF it only has 2 wires? The VHF NEMA connection has 4 wires? Not sure where to go from here?

My other concern is in connecting 2 VHF radio's. Supposedly the converter can handle up to 3 different connections so I am guessing I could just splice both radio NEMA connections into one?

Sixteen days to launch!

 

[Iggy]

Most new VHF are NMEA2k. Which would make this a whole lot easier. I would stay away from 0183, its slow and not plug and play.

What model VHFs are you using?

 

[Pat T]

Most new VHF are NMEA2k. Which would make this a whole lot easier. I would stay away from 0183, its slow and not plug and play.

What model VHFs are you using?

I bought Icom M424G and it is 0183.

 

[Cigatoo]

Digital Selective Calling is part of the radio. No data connections needed for that. The manual says that the 424G has internal GPS so it will have your location for emergency DSC calls. Not sure what you are trying to accomplish AIS wise? What do use for AIS now? There is no AIS receiver in that radio.

 

[Statistical]

It is only two wires.

Does your converter port look like this:
https://www.brommeland.no/file/stan...rter-installation-instructions-87256-1-en.pdf

Note install diagram on for VHF NMEA 0183 on page 22. Your VHF wiring harness may have more than two wires as the other wires have other purposes check VHF manual.

Note NMEA 0183 is only point to point so once you get this working if you want support on the other radio you will need a second converter and do the same process. It is annoying that literally 23 years after NMEA 2000 became a thing the radio companies are still selling new radios without N2K ports.

 

[Iggy]

Digital Selective Calling is part of the radio. No data connections needed for that. The manual says that the 424G has internal GPS so it will have your location for emergency DSC calls. Not sure what you are trying to accomplish AIS wise? What do use for AIS now? There is no AIS receiver in that radio.

If the AIS, GPS and VHF all communicate. Than you can pick a AIS target from the GPS and call it.

 

[Pat T]

Digital Selective Calling is part of the radio. No data connections needed for that. The manual says that the 424G has internal GPS so it will have your location for emergency DSC calls. Not sure what you are trying to accomplish AIS wise? What do use for AIS now? There is no AIS receiver in that radio.

Hey Carl. Thanks for the response. As I understand it you can select an AIS target from your plotter and then make a call to that target boat w/o having to go through entering the MMSI . (On page 69 of the manual.) So, thus the need to connect my VHF to my backbone to include the MFD and AIS systems.

 

[Cigatoo]

If the AIS, GPS and VHF all communicate. Than you can pick a AIS target from the GPS and call it.

 

[Pat T]

It is only two wires.

Does your converter port look like this:
https://www.brommeland.no/file/stan...rter-installation-instructions-87256-1-en.pdf

Note install diagram on for VHF NMEA 0183 on page 22. Your VHF wiring harness may have more than two wires as the other wires have other purposes check VHF manual.

Note NMEA 0183 is only point to point so once you get this working if you want support on the other radio you will need a second converter and do the same process. It is annoying that literally 23 years after NMEA 2000 became a thing the radio companies are still selling new radios without N2K ports.

Statistical, thanks. Yes that is the converter I have.
The VHF manual shows it has 4 wires to choose from to connect to the 2 wires to this converter. You choose one of the following:
* Talker/Data Out - to connect to NEMA input lines of navigation equipment, to receive position data of other ships.
* Listener/GPS In - to connect to NEMA output lines of a GPS receiver for position data.
Each side has 2 wires, a negative and a positive. My guess is to use the Talker/DataOut wires?

 

[Statistical]

Statistical, thanks. Yes that is the converter I have.
The VHF manual shows it has 4 wires to choose from to connect to the 2 wires to this converter. You choose one of the following:
* Talker/Data Out - to connect to NEMA input lines of navigation equipment, to receive position data of other ships.
* Listener/GPS In - to connect to NEMA output lines of a GPS receiver for position data.
Each side has 2 wires, a negative and a positive. My guess is to use the Talker/DataOut wires?

The wording of those sounds reversed. My first thought would be "Listener" but the description seems to be the reverse.

 

[heysteve]

Sadly, I don't think you'll be able to make this work.

For the radio to make a call, it must receive a message saying essentially "please make a DSC call to MMSI 12345678". The Icom 424 manual doesn't mention this capability at all. There is a vague mention of DSC data output but that may be related to received distress call information (like location).

I actually tried this a couple years ago. I had an Icom 504 connected directly to my Axiom Pro (it had 0183 wires out the back) and was never able to make it work. I've only seen it work when all equipment including the radios were from the same vendor.

Icom does have excellent technical support so it might be worth a call to them and see what they say.

 

[twistedtree]

Sadly, I don't think you'll be able to make this work.

For the radio to make a call, it must receive a message saying essentially "please make a DSC call to MMSI 12345678". The Icom 424 manual doesn't mention this capability at all. There is a vague mention of DSC data output but that may be related to received distress call information (like location).

I actually tried this a couple years ago. I had an Icom 504 connected directly to my Axiom Pro (it had 0183 wires out the back) and was never able to make it work. I've only seen it work when all equipment including the radios were from the same vendor.

Icom does have excellent technical support so it might be worth a call to them and see what they say.

i believe this is correct. There is no standard in NMEA 2000 for a plotter or AIS or anything to initiated a DSC call on VHF. In teh few places where it can be done, it's because the plotter or AIS and VHF vendor are the same and they are using some proprietary messages to make it work.


I think some time ago I found 0183 messages to do this, but I have never seen a VHF that supports it, nor a plotter or AIS.


The messages that ARE standardized are for incoming DSC messages, especially emergency messages. If set up correctly, this will plot on your chart plotter when there is a distress call.

 

[Iggy]

On my last boat I had all Garmin. The Plotter would show a AIS target. I could tap on it and call that target though its MMSI#.

I now have all Simrad and I have not tried it. But both where/are NMEA2k, and the Simrad manual says you can.

 

[Statistical]

The other options is for sending all AIS data to the radio (for a radio) that doesn't have AIS so you can pick the AIS target on the radio to start a DSC call. The OP radio model doesn't support that though (not all do).

I use this on my M605. It is sad that radio companies have been so slow to incorporate things like this because being able to pick the target to start DSC vs manually entering the MMSI makes it a lot more useful.

 

[twistedtree]

The other options is for sending all AIS data to the radio (for a radio) that doesn't have AIS so you can pick the AIS target on the radio to start a DSC call. The OP radio model doesn't support that though (not all do).

I use this on my M605. It is sad that radio companies have been so slow to incorporate things like this because being able to pick the target to start DSC vs manually entering the MMSI makes it a lot more useful.

That is an interesting work around. Thanks for posting.

 

[twistedtree]

On my last boat I had all Garmin. The Plotter would show a AIS target. I could tap on it and call that target though its MMSI#.

I now have all Simrad and I have not tried it. But both where/are NMEA2k, and the Simrad manual says you can.

Each of these is done with proprietary messages.

 

[Pat T]

I watched a VHF tutorial a couple years back that mentioned this feature, that of selecting an AIS target from your plotter instead of entering the MMSI manually, and thought that it would be more commonplace on a new VHF. So when I installed my new Icom's I thought it would be included. The title on page 69 of the VHF manual is " Making an Individual call using an AIS transponder." Yes, just as I thought, I'm almost there! But I know I must have further connections to make and thus my call out to TF.

Back to the manual. It reads that when the optional MA-500TR/MA-510-TR CLAS B AIS Transponder is connected ...............you can make this type of call. What they don't tell you though is that the above AIS units are also Icom brands. Maybe I should have known. So as some of you have mentioned you need both radio and AIS made by same manufacturer for this to work.
So looks like there is no need for me to do anymore work on my VHF. This is OK too since now have 15 days till launch!

Thanks again all.