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Witte C · 08-09-2021, 07:15

I am new to NMEA 2000 systems, but published manual information from Lowrance HDS Live chartplotter states "If the system includes a VHF radio supporting DSC calls over NMEA 2000 or NMEA 0183, a DSC call can be
initiated to other vessels from the unit."

Standard Horizon GX1850 VHF documentation states, "Easy plug and play connectivity to the NMEA bus. A single plug in interface allows connectivity of GPS data, and DSC calling between compatible devices."

Does anyone know what to do to make this work for DSC calling via chartplotter (e.g. Lowrance HDS Live and GX1850)? NMEA 2000 is not working, but I wonder if NMEA 0183 will work if connected.

goboatingnow · 08-09-2021, 07:17

I have an 1850 Dsc calls can be made from the raymarine plotter , is the radio set up for dsc in the first place

Witte C · 08-09-2021, 08:08

I have not changed any settings related to setting it up for DSC, but I have sent test DSC transmission to USCG 20 miles offshore and reply was successful.

What do you mean by setup for DSC?

The overall system has HDS Live, GX1850 and EM-TRAK B951 AIS all connected via NMEA 2000. The HDS Live shows both AIS and DSC vessels on chartplotter and lists them on vessels page, but the "call" button for all vessels is "greyed out" disabled. I am not sure how to get this feature to work properly.

Witte C · 08-09-2021, 08:11

The chartplotter is where the "call" button is "greyed out". The DSC function on the VHF unit works properly, but keying in 9 MMSI digits on VHF unit while underway is what I'd like to avoid if possible. Being able to press "call" on MFD is obviously faster/easier. This is partly why I chose these units...just not working as advertised yet.

ranger58sb · 09-09-2021, 05:21

Quote:

Originally Posted by Witte C

I am new to NMEA 2000 systems, but published manual information from Lowrance HDS Live chartplotter states "If the system includes a VHF radio supporting DSC calls over NMEA 2000 or NMEA 0183, a DSC call can be
initiated to other vessels from the unit."

Standard Horizon GX1850 VHF documentation states, "Easy plug and play connectivity to the NMEA bus. A single plug in interface allows connectivity of GPS data, and DSC calling between compatible devices."

Does anyone know what to do to make this work for DSC calling via chartplotter (e.g. Lowrance HDS Live and GX1850)? NMEA 2000 is not working, but I wonder if NMEA 0183 will work if connected.

In the fine print of each manual, you may find out which sentences are transmitted back and forth over NMEA 0183 and which PGNs travel on NMEA 2000. I suspect that's where some mis-match can occur.

On our previous system, the plotter would have responded to DSC emergency calls had it been fully connected to the radio via NMEA 0183... even though the (eventual replacement) radio primarily used NMEA 2000 to acquire location info from the GPS.

Then too, IIRC that particular plotter wouldn't handle ALL DSC calls; only response to emergency calls.

Quote:

Originally Posted by Witte C

The chartplotter is where the "call" button is "greyed out". The DSC function on the VHF unit works properly, but keying in 9 MMSI digits on VHF unit while underway is what I'd like to avoid if possible. Being able to press "call" on MFD is obviously faster/easier. This is partly why I chose these units...just not working as advertised yet.

The radio might offer a way to pre-enter and save MMSIs, if it happens you're focused on a library of friends and family.

I can't remember ever making a DSC call after once I proved our radios would do it... so I'm not an authority on all that.

-Chris

**s/v Jedi** · 09-09-2021, 05:31

I can confirm that the Standard Horizon GX1850 does not send the correct NMEA2000 PGN’s. I have tested this with a data sniffer.

The B&G V50 (?) that I also have is a cr@p radio but it does send the correct PGN’s. I have been unable to find a good radio that does everything right on NMEA2000 as well, but I have hopes the B&G V100 will be when it really comes available. Much higher price tag though.

Also, the GX1850 is a b|tch when it comes to receiving position from the network. It’s software is seriously bugged and their US support is terrible. VHF radio manufacturers are the last ones that need to learn NMEA2000 support; we’ve seen the same disgusting behavior from chartplotter manufacturers before.

Witte C · 09-09-2021, 05:33

Thanks for the info. I researched things you described and ultimately received feedback from Yaseu Standard Horizon and they said it would not work due to chartplotter proprietary sentences.

**s/v Jedi** · 09-09-2021, 08:27

Quote:

Originally Posted by Witte C

Thanks for the info. I researched things you described and ultimately received feedback from Yaseu Standard Horizon and they said it would not work due to chartplotter proprietary sentences.

That is true… however, when a DSC position is received, there is a standardized PGN to send that puts it on a plotter. They do not send that, even though they claim so in their documentation.

The proprietary PGN’s are used to set up a DSC individual call with a target on the plotter. I would be happy to just see the DSC target on the plotter.

The Standard Horizon radios NMEA2000 port is very problematic. When you scan the network for a position source, it can only find a handful of network devices. Furthermore, it can only detect a GPS when the NMEA2000 is switched on -after- the radio is switched on. They need to see an initial network transmission from the GPS. There is no excuse for this as other radios do it very well, and their US support manager takes it badly.

CarinaPDX · 09-09-2021, 13:46

What a mess - I had no idea that it still was not possible to select an AIS target on a chartplotter and have a DSC call initiated on a VHF via an N2K PGN. IIRC there was one company (Navico?) that had a proprietary solution a decade ago, but not having standard PGNs implemented for calling selected targets at this point is a real disappointment. I just did a quick glance at Icom's VHF radios and it appears they only have the ability by using radios with internal AIS systems, not via N2K. The latest Furuno TZ3 MFD doesn't have a PGN for it, and it looks like the VHF radios support it through integrated AIS as well. It seems so obviously valuable, as opposed to dealing with long MMSI numbers, that it is just bonkers not to have it.

Greg

rwidman · 09-09-2021, 13:49

Quote:

Originally Posted by Witte C

................ NMEA 2000 is not working, but I wonder if NMEA 0183 will work if connected.

Why not try it?

That is how mine is connected.

CarinaPDX · 09-09-2021, 14:17

NMEA 0183 will work for GPS and AIS data but I don't think there is a sentence for passing an MMSI calling number to a VHF in 0183. Check the specs on your units but I don't think you will find such a sentence.

Greg

Dsanduril · 09-09-2021, 15:23

NMEA really missed the boat with DSC and N2K. AFAIK there is still only PGN 129808 to send DSC information from the radio to a chartplotter, and it was really designed to send only DSC distress calls, although it has been pressed into service for all calls (leaving the "nature of distress" field blank). But that leaves room for "interpretation" by vendors.

Then NMEA found that they hadn't really set up the PGN fields properly in the first place, so they issued a technical note on how to use the PGN.

And then they issued a PGN database with the fields scrambled, so any vendor that used database version 2.1 from February 2015 got it wrong out of the box.

https://www.nmea.org/Assets/20150328...on%202.100.pdf

Note that the first release in 2013 of the technical note said "NMEA has begun development of a new set of DCS PGNs to replace the current PGN 129808". I thought I had read recently that they had actually been released, but if I did I can't find it any more.

Witte C · 09-09-2021, 18:11

Thanks for all the support helping identify current limitations on chartplotter-initiated DSC calls not being possible on all equipment. Apparently, some manufacturers make this work if the same brand is combined for Vhf & chartplotter.
I suspect an improvement (possibly firmware update) will occur in future.

On a good note though…all other desired DSC and AIS data successfully transfers to chartplotter including position sports and DSC distress calls. So at least we can see it on the map and hear on radio.

I’ve learned over the years we humans have become so complex with technologies that we are unable to successfully implement everything created to a level of our expectations. Simple systems are usually most reliable and implemented easily.