Help! Which DSC radios are compatible with which plotters?

[s/v Jedi]

What a mess, information is impossible to find and it’s obvious there are many problems.

I hate it that my new Standard Horizon radio says it works with “compatible plotters” but nothing more meaningful and then don’t plot received position reports on my B&G Vulcan.

Or, when I select “call ship” on my plotter the radio does nothing, while my B&G V50 sets up the call. Now that one is probably vendor specific but plotting DSC received positions should work, right?

Not to skip the problems radios have with support for nmea2000 which is directly related to these problems. I have the US manager of Standard Horizon denying the problems with a straight face even though there are many fora threads reporting these same problems and his slacking response.

So how about we report compatible/incompatible combinations here and I’ll make a summary for reference. I plan to sniff the nmea2000 to see what PGN’s the radios transmit and receive.

I do hope there’s members willing to dive this deep into it as it feels lonely in this quest

[ranger58sb]

I haven't read about difficulties with plotting... although I did see that a plotter may be set up to receive DSC/AIS info from the radio via either NMEA0183 or NMEA2000 (maybe not both) and a radio may be set up to transmit to the plotter via either (maybe not both)... and ya gotta get those to match.

IOW, just because a plotter has a 0183 and a 2000 input/output, and a radio has a 0183 and a 2000 output/input... doesn't mean instant compatibility for plotting... and it all depends on which protocol the DSC/AIS data uses on that hardware.

When I began understanding our plotter ought to be able to initiate a DSC/AIS call through our radio... I discovered the plotter and the radio would only handle DSC/AIS data on NMEA0183. No problem. Plots worked fine. But then I eventually discovered our installer didn't connect the NMEA0183 OUT from the plotter to the NMEA0183 IN on the radio. Couldn't initiate DSC/AIS calls from the plotter, even though the plotter itself supported that. Never figured out why the wire wasn't connected as a matter of routine. In any case, it could have been an easy fix.

Other folks were at the same time recommending it all might work nicely if the plotter and the radio were the same brand... but that was sort of a non-solution for us...

-Chris

[rslifkin]

As a thought on the DSC position plotting, if you have AIS, that should receive DSC calls and do that job. Meaning it doesn't matter if the VHFs are giving that data to the plotter(s) or not.



However, getting the calling feature to work would be convenient. But I'm now thinking about it, and I wonder: if you have multiple VHFs, how do you avoid all of them trying to initiate the DSC call?

[ranger58sb]

Originally Posted by rslifkin

However, getting the calling feature to work would be convenient. But I'm now thinking about it, and I wonder: if you have multiple VHFs, how do you avoid all of them trying to initiate the DSC call?

We only connected one of our two fixed VHFs to the plotter.

-Chris

[s/v Jedi]

I was assuming we were all aboard the nmea2000 network system where everything connects to a backbone instead of one device to another.

I have two radios, when a dsc individual call comes in, both radios ring. Of-course in normal use I only have one radio turned on.

AIS receivers/transponders do not do anything DSC related. Also, I’m having trouble plotting DSC targets. I do get them now and then but I need to sniff the network to find out details.

It doesn’t look good, it’s like the early days of nmea2000 on plotters where it only worked half if lucky.

[rslifkin]

Originally Posted by s/v Jedi

AIS receivers/transponders do not do anything DSC related. Also, I’m having trouble plotting DSC targets. I do get them now and then but I need to sniff the network to find out details.

Most AIS transponders I know of have a DSC receiver in them. My understanding of it is that they should receive and plot a DSC emergency call (but not handle any other DSC functions).

[ranger58sb]

Originally Posted by s/v Jedi

I was assuming we were all aboard the nmea2000 network system where everything connects to a backbone instead of one device to another.

Yeah, I thought that too...

Then learned otherwise. Our main equipment was new in 2009, though, so I'd have guessed strides since then. Au contraire. Replaced the VHFs in 2018, yes they now had NMEA2000... but no, they didn't transmit DSC position reports that way, only via NMEA0183.

-Chris

[Martkimwat]

Originally Posted by ranger42c

Yeah, I thought that too...

Then learned otherwise. Our main equipment was new in 2009, though, so I'd have guessed strides since then. Au contraire. Replaced the VHFs in 2018, yes they now had NMEA2000... but no, they didn't transmit DSC position reports that way, only via NMEA0183.

-Chris

You could maybe try calling Standard Horizon UK (by Skype?) as I have found their technical department exceedingly helpful, number is +44 1962 866667 (It's actually Yaesu UK but they are the dealers/suppliers for Standard Horizon in UK) or if you have the time, email them your query although they might bounce you back to the US if they see your US email address.

[ranger58sb]

Originally Posted by Martkimwat

You could maybe try calling Standard Horizon UK (by Skype?) as I have found their technical department exceedingly helpful, number is +44 1962 866667 (It's actually Yaesu UK but they are the dealers/suppliers for Standard Horizon in UK) or if you have the time, email them your query although they might bounce you back to the US if they see your US email address.

Thanks, that may help Jedi and others.

(We sold that boat last June, and the radios were ICOM.)

-Chris

[hzcruiser]

Originally Posted by s/v Jedi

Or, when I select “call ship” on my plotter the radio does nothing, while my B&G V50 sets up the call. Now that one is probably vendor specific but plotting DSC received positions should work, right?

[...]
I plan to sniff the nmea2000 to see what PGN’s the radios transmit and receive.

I don't have NMEA2000 (yet) but re "DSC received positions": do you mean AIS received positions, as DSC, to my knowledge, is not about position reporting.

Like you said, your best bet in this wild west of PGNs would be to have a device that would allow you to see all the packets. Better even, if that device could send out PGNs itself for testing.

There are a few raspi based solutions out there, IIRC.

[Jammer]

Originally Posted by hzcruiser

I don't have NMEA2000 (yet) but re "DSC received positions": do you mean AIS received positions, as DSC, to my knowledge, is not about position reporting.

DSC defines a "position request" and a "position report" message. They are not widely used, but are supported by all DSC-capable radios. I am planning to use them to share positions between my mothership and dinghy, and understand that there are a handful of people who use them to share positions among a group of boats sailing together.


When a DSC call is received it arrives without position data, but a capable chartplotter can look up the IMSI and see if the same vessel's position was previously received via AIS.

[hzcruiser]

Originally Posted by Jammer

DSC defines a "position request" and a "position report" message. They are not widely used, but are supported by all DSC-capable radios. I am planning to use them to share positions between my mothership and dinghy, and understand that there are a handful of people who use them to share positions among a group of boats sailing together.


When a DSC call is received it arrives without position data, but a capable chartplotter can look up the IMSI and see if the same vessel's position was previously received via AIS.

That's good to know and might help S/V Jedi!

So if his Vulcan is not actively polling his VHF radio it doesn't receive that info.

[Boatyarddog]

Originally Posted by hzcruiser

That's good to know and might help S/V Jedi!

So if his Vulcan is not actively polling his VHF radio it doesn't receive that info.

Could it be The MMSI information is missing from the VHF?
It can only be programmed in 1 time, per unit on most radios to receive D.S.C Calls.
I'm guessing on this.
SV Cloud Duster

[tanglewood]

Taking a quick look at the published N2K PGNs, I only see one related to DSC, and it appears to be used to communicate a DSC distress call. It doesn't look like it describes an incoming non-distress call, nor is it a mechanism to initiate a call. So I think the only standardized functionality is for the VHF to send the PGN (129808) when a distress call is received, and for the plotter to receive that PGN and plot the location and nature of the distress.


There don't appear to be any standard PGNs to initiate and receive other calls. So where that's done between same-vendor plotters and VHFs, it's done via proprietary messages. Pretty lame, but not surprising.


So I think any compatibility chart will just be full of "Nos" except for a few cases where the plotter and VHF are from the same vendor.


As for compatibility between VHFs and plotters for plotting distress calls, keep in mind that N2K certification does not test for proper formation of transmitted messages, nor for proper interpretation of received messages. So it's anyone guess what will work with what, and if something doesn't work, you can be sure one vendor will point the finger at the other vendor. But under no circumstances will they get together, test their products together, and work out compatibility issues.

[waterman46]

Originally Posted by Jammer

When a DSC call is received it arrives without position data, but a capable chartplotter can look up the IMSI and see if the same vessel's position was previously received via AIS.

I'm thinking that lookup actually does happen in the VHS AIS receiver, so I'm not sure it's necessary for the chartplotter to do that.

Assuming the VHF has AIS and DSC receive functions, such as the GX2400, and you have it connected to the chartplotter to show AIS targets, perhaps the VHF data sent to the chartplotter will contain a flag to show which AIS target sent the DSC call.


We have the SH VHF and it sends AIS information to our B&G Zeus chartplotter but I have not myself done any checking what the chartplotter will show in case of a DSC call.