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NMEA 0183 to SeaTalkNG?

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I've got a CV7 ultrasonic wind transducer atop my mast, hoping to replace my Raymarine wand with something more accurate. My instrument system is currently a SeatalkNG backbone with two ST70s, and three older ST60s acting as repeaters.

The CV7 sends NMEA 0183 sentence MWV. SeatalkNG needs PGN 130306. What's the best way to get this data on the network? (My Brookhouse iMux combines this wind data with converted SeaTalk1 data from other instruments and sends it out via Wifi but, as far as I can tell, does not rebroadcast it on the SeaTalk1 network. Even if it did, I wonder if the ST60 or ST70 would receive it.)

I'm considering an Actisense NGW-1. Are there other alternatives?

If I do manage to get this PGN to SeaTalkNG, can anyone tell me, (Raymarine says this is 'uncharted territory'.), if an ST70 head unit will then make True Wind calculations. Can/will the ST70 display make these calculations from raw data on the bus, or does it require direct communication with its wind pod to do this?

Any advice helpful.

Thanks and Cheers,

9 Replies

  • Doug,

    One solution is to add an MFD. My Raymarine e-series classic MFD does all the conversions for me in a similar situation with a Airmar PB200 ultrasonic wind when it was set to provide MWV. I used it in this configuration for two years (since then I use the NMEA2000 output of the PB200). It was very effective and trouble free. The MFD combined STW from seatalk to calculate true wind, true wind then appeared on my seatalk connected ST60 wind repeater and NMEA-2000 connected ST70 displays as the MFD did all the conversion between NMEA-0183, NMEA-2000, and seatalk effectively.

  • Dan,

    Thanks for your quick response. So, an E-Series MFD will do the job. Raymarine hinted at this, suggesting '...the e-series is a whole 'nother critter...'. As interesting as their e7 MFD is, I'm not ready just yet to line up for one.

    Would you guess, (does anyone know?), if placing PGN 130306 on the SeaTalkNG bus via a spur cable would provoke an ST70 into calculating True Wind info? This is the NGW-1 option I refer to above.

    Another option is a conversion box offered by lcjcapteurs, which converts MWV from their CV7 to an ST60-compatible signal (which I believe should mimic the output of a Raymarine wind transducer) and, presumably, could be wired wired directly to my Wind Pod. We might even be off and running. Well, save for deleting the calibration values for my old wand that are held in the Pod, and calibrating the CV7 (which is done externally via supplied software). It seems a bit ridiculous, converting a perfectly good NMEA 0183 sentence to signal, then back to NMEA 2000 via Pod but, hey, it may be a solution.

    Whew! Your thoughts?


  • The ST70 wind pod input is identical to the ST60 wind display instrument. So the lcjcapteurs would be a solution. Does the lcjcapteurs come with the little terminal clips you push onto the terminals on the ST70 pod? If not, they are hard to find, best bet is to find a raymarine installer to buy them from.

  • Dan,

    Christophe at lcjcapteurs indicates that their Option ST mimics the older Rotavecta transducer and, as such, must be wired directly to the Rotavecta terminals at the back of an ST60 display for it to work across the system(s). A new version which will mimic their current 5-wire masthead transducer, and which could therefore be connected to a Wind Pod, is in process and may be available early next year.

    In my SeaTalkNG system, my ST60 display is now being used as a repeater. If I turn kit into a master unit, will it send this data over to the SeaTalkNG side for my ST70s to display? Is it bi-directional, or one-way - SeaTalkNG to SeaTalk1?


  • Doug wrote "In my SeaTalkNG system, my ST60 display is now being used as a repeater. If I turn kit into a master unit, will it send this data over to the SeaTalkNG side for my ST70s to display? Is it bi-directional, or one-way - SeaTalkNG to SeaTalk1?"

    Not familiar with what you mean by "if I turn kit into a master unit". My experience was that the ST60 on my boat would start/stop calculating (and transmitting over seatalk1) true wind based on the presence of a transducer signal on the ST60 wind display. Disconnect the transducer, recycle power, and it would stop.

    I partially know your ST70 answer, as there was a time I was testing the ST70 without the MFD connected. If your ST70 (connected to seatalk1 only, or seatalk1 and NG) question is "will the ST70 then display apparent and true wind from the ST60" the answer is YES. If the question is, will the ST70 retransmit over NG, I don't know (does it matter?).

  • Dan,

    An update... After Christophe's surprise that I was unable to see Apparent wind info on my system after connecting to the NMEA IN port of my S1G, I went over my wiring. Also, I disconnected the ST70 Wind Pod from the system. Now, I am receiving Apparent wind info on all instruments, ST60s and ST70s. It also appears I am getting True Wind info. I have not had a chance to get away from the dock to test, but my ultrasonic speed always seems to read a few tenths of a knot of current (or noise) so this appears to be generating the slightly different data being displayed as True Wind direction and speed.

    I can't say for certain where the True Wind calculations are actually being made in my system. It's currently a bit of a mystery. However, my ST70s are displaying this data which is coming from the SeaTalk1 side. So, for now, it seems to be working as hoped.


  • I am curious which product is calculating true wind, look forward to you posting the answer.

  • Well, my guess is the autopilot is making the calculation and broadcasting it on SeaTalk1. My AP is only on the SeaTalk1 network, as is my ST60 Wind display. The ST70 display(s) must allow bridging since they, too, are displaying Apparent Wind info which originates on SeaTalk1. Furthermore, I have removed the Transducer wires from the back of my ST60 Wind display, and should be acting solely as a repeater. Here's what the ST60 Wind Owner's Handbook has to say about that:

    "In a SeaTalk system, each instrument can be either a master or dedicated repeater unit. A master instrument is directly connected to a transducer (the device that provides the raw data), and provides data and control appropriate to its function, to all other equipment on the SeaTalk network. A repeater instrument is not directly connected to a transducer but displays information provided by other equipment in the SeaTalk network. '

    So Raymarine says the ST60 display should be acting as a repeater here. And I would be very surprised if an ST70 display would undertake True Wind calculations from Apparent Wind data available on the SeaTalk1 bus, but it certainly is possible.

    When I get a chance to poke the black box(es) some more to see what's inside, I'll let you know what I find.


  • Dan,

    If I place MWV at the NMEA terminals of my S1G Autopilot at 4 Hz, my ST60 display (response setting all the way up) smoothly tracks AWA/AWS and TWA/TWS in near real time. Curiously, the bridged ST70 displays show discreet updates only once every 4 seconds.

    If I place MWV at the NMEA terminal of Raymarine's Seatalk-NMEA Converter box, and connect the output of this box to the Seatalk1 bus, both ST60 and ST70 displays appear to smoothly track wind data in near real time.

    In both configurations, MWV is only broadcast on the Seatalk1 bus at that same 4 second interval. Leaves me to wonder what's going on, frankly.

    As a further observation, no True Wind data is ever present on the Seatalk1 bus as far as I can tell, which leads me to conclude that this data is discreetly calculated within each display.

    Your thoughts?