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DSC plots on Navnet3D

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Reading through the NMEA 2000 PGN details that the NMEA finally posted on their site (and whose presence Kees alerted me to in his blog), I was intrigued to see that the DSC PGN (129808) seems nicely fleshed out.

Curious whether my Furuno plotter could do anything with that PGN if it received it, I looked through the NN3D spec sheet and found that Furuno does indeed claim to support "input" of 129808.

Unfortunately I don't have a radio that outputs NMEA 2000 (such as the Garmin VHF 300). My Standard Horizon Matrix AIS outputs 0183 DSC sentences (DSC & DSE), but the Actisense NGW-1 doesn't (yet, anyway) convert them to 129808.

I suppose I could just connect the Matrix's 4800 baud output to one of the NN3D 0183 inputs, but in any case I see nothing in the NN3D MFD manual about DSC messages. Has anyone tried this, either via 0183 or 2000?



12 Replies

  • maxsea timezero supports dsc so guess it will come to nn3d via a sw upgrade at somepoint

  • Ah I see that was added in 1.9. I wonder if MSTZ will get the DSC sentences from NN3D? I'll ask Furuno and see what they say.

  • That PGN allows your MFD to show who is in distress or who is calling you.

    That is only half the deal, and the less interesting one at that. The really cool bit would be where you could point at an AIS target on the MFD and say "Call that boat".

    I was the subject of a direct DSC call by someone I know last weekend, and it really got our attention, we switched to the proposed channel and had our conversation. Pretty cool.

    Now only if we could do this from our MFD screen without needing to punch in the MMSI on the VHF, with any brand of MFD and any brand of VHF (well we can dream can we?)

  • So my first comment was in response to another reader's comment that I received via email but appears never to have been posted. He noted that MaxSea TZ does support DSC target identification.

    Kees, it is interesting to note that the NN3D specs also say that the MFDs can output 129808 as well. However, given that there is no plotter UI for selecting a target to call, and that my radio doesn't input DSC or DSE sentences (I think), that "capability" seems moot.

  • My bad, Adam; a few unapproved Forum comments got by me. I think I have heard Furuno say that DSC support is coming to NN3D.

    Kees, Garmin MFDs and VHF radios support that "direct dial AIS target" feature well. But I'm not sure if they're doing it with standard PGNs or had to write something proprietary. I also haven't had much luck getting yachts or even ships to answer those direct DSC calls. Most everyone is still very unfamiliar with the process.

  • a friend in Furuno Europe has shown me the release notes for software 2.06 and DSC plotting is included.

    Whether this is via 0183 or 2000 remains unclear.


    anyone managed to get this yet ? the french link doesnt work and mynavnet says 2.05 is the latest and Furuno USA website is giving out the 2.05

  • Ever since Ben has put me onto it I am looking at the Standard Horizon HX851 DSC handheld VHF radio as the ideal MOB device. For it to have a position indicating function in addition to the alarming you need a chartplotter or software displaying it's position (supporting PGN 129808 or NMEA sentences DSC and DSE). So unlike Kees I find this particular function the more interesting one but the other, setting up a DSC call on the radio via the MFD, is certainly nice to have.
    Here is what I have learned so far:
    - PGN 129808 is incorrectly listed as 12808 on the NMEA site. I sent them a mail on July 16 but it's still wrong today
    - NMEA 0183 sentences DSC and DSE belong together, forming a pair (which I have not seen anywhere else in NMEA 0183). DSE was retrofitted to supply the missing decimal digits to the minutes and degrees of the position contained in DSC. This is a really ugly fix. Why did they not make DSE a copy of DSC with just the missing data added? This raises all sorts of problems if one is received but not the other or DSC is received and DSE 5 minutes later. Remember, this data is typically sent only once and not once every few seconds
    - the Standard Horizon Matrix GX2000 fixed VHF radio outputs NMEA 0183 DSC and DSE but no NMEA2000
    - this radio will also output these sentences on a position received in response to a DSC position request it has sent itself and which was replied to by another radio
    - Coastal Explorer 2009 reads NMEA 0183 DSC and DSE to put a red dot with the MMSI below on the chart. Repeated calls from the same MMSI will move the dot not put several dots. The dot will remain in place until CE is closed. All other information such as nature of call (individual, safety, urgency, distress), time and so on is not there yet but planned. PGN 129808 is also planned but not there yet.
    - There are two NMEA 0183 sentences "DSI: DSC Transponder Initiate" and "DSR:DSC Transponder Response". Maybe these are for instructing a radio to set up a DSC call. Does anyone know?

    To make (initiate) a DSC individual call you must press a button to initiate a call, then enter the MMSI to call, then press another button, then enter the channel (which you should have verified before to be clear), the press amother button for "go". Any kind of integration with an MFD or AIS will only do for you the frist button and entering the MMSI, not send out the complete call. That wouldn't be legal because you must chose the channel yourself. The called party must then only press a single button to accept the call and have the radio switch to the channel requested by the caller.

    The HX851 is highly illegal in Germany since a DSC radio must be fixed not mobile so the HX851 cannot ever be issued it's own MMSI so you must use the same MMSI as that of the fixed radio which is a good idea anyway and recommended by ofcom but also totally illegal in Germany. Great! So I have never said any of this and this post isn't even from me.

    One or two things can go wrong with using the same MMSI, though
    - the handheld's MMSI is the same as that of the fixed radio so the fixed radio must not reply to it's own position request
    - the MFD or charting software must not suppress display of a DSC position from this MMSI even if it is suppressing an AIS target with this MMSI

    The Matrix GX2000 provides some of the feature asked for by Kees because it dislays all AIS targets in it's display and lets you hit "call" on the one you want.
    The Simrad AI50 class B transponder also allows to do this, even graphically I think, but only with a Simrad radio. If this could ever be done with an MFD it would have to be via a proprietary PGN which means the MFD and the radio must be from the same manufacturer. PGN 129808 is saying "MMSI number ... is calling you with a call of nature ... and is at ... position". What would be needed is another PGN, possibly corresponding to 0183 sentences DSI and/or DSR, to mean "I the MFD ask you the radio to call MMSI ..."

    I plan to attach this handheld VHF to my kid once she goes out alone in the dinghy so that I can press a button on the boat's radio and get a dot on the chart with her position whenever I want to. It'll be two years before she might begin to do that and I hope the various manufacturers use that time as follows:
    - Standard Horizon should make a smaller not floating version of the HX851
    - Standard Horizon should put NMEA2000 on their radios
    - Navico should put the class B static data PGN into the AI50 as well as all the obscure AtoN and other targets and safety related messages
    - Navico should make my RS82 VHF radio output PGN 129808 (they use a proprietary PGN at them moment as Kees has found out for me; many thanks!) and teach it to send a DSC position request and also ouput PGN 129808 on the position received as a response to it. It would be nice if they also make it reply to a position request but from my perspective, that's optional.
    - Actisense should update the NGW-1 software to translate the pair DSC and DSE to PGN 129808
    - NMEA should fix their website on 12808
    - NMEA should define a PGN to set up a DSC call
    - Rose Point should add support for PGN 129808 to CE

    From my perspective, Navico's tasks are the most important. If they don't deliver, I won't be buying an AI50 and my RS82 will go on eBay.

  • Excellent work, Henning. Thanks so much for sharing. How about writing a guest entry about your investigations and what how you'd like to see the manufacturers support DSC?

  • At the moment, this would be mostly a list of what doesn't work, why it doesn't work and what would be needed to get it to work. I have just ordered the HX851 (again, this is not me writing this ;-) but as of now, with my existing RS82, I cannot send a position request to be replied to by the HX851.
    If that is what you have in mind then, yes, thank you for the honor. I would like to enlist the co-authorship of Kees, though.
    I will try to get a working solution set up over the winter, maybe even rig an emergency antenna to be able to test with the boat in the shed. This should give a clearer picture by springtime so we could also wait until then.

  • Adam, I'm sure you've figured this out by now,but Navnet3D 2.05 definitely does NOT support any DSC data input from a VHF radio. There is not even an applicable "Port Sensor Type" on the installation wizard setup. We connected an Icom-M602 (which outputs DSC and DSE version 3.01) to NMEA Port 2 on the MFD and got nothing on the Port Monitor.
    Version 2.06 apparently WILL support it (in response to our and I'm sure others' complaints), but I haven't seen a screen shot of the setup screen, and last I heard the new software won't be available till at least March 2011.
    Hope this helps -