ComNav Class A AIS transponder, with NMEA 2000!

... written for Panbo by Ben Ellison and posted on Dec 14, 2009
ComNav Compact Class A AIS.jpg

Very cool!  It looks like the compact and relatively inexpensive Class A AIS Transponder that SRT teased last summer is not only getting close to real, but that it will also -- nice surprise -- have NMEA 2000 output (in addition to regular NMEA 0183 HS and RS232 PC outputs).  The ComNav data sheet is available here (thanks, Dave!), but there are some caveats...

For one, the Voyager X3, as ComNav is calling it, is not yet FCC approved and therefore it's not yet for sale in the U.S.  And the price is not listed (I've asked), so we don't yet know if ComNav met SRT's hoped for "less than $2,000 retail."  Plus, the N2K output won't come until a software upgrade is issued in "late 2010."
   But given all those caveats, this sure looks like an interesting new option in AIS.  At 8"W x 4.2" H x 5.4" D, the Voyager X3 is sort of similar to the neat Simrad AI-50, only with the ability to transmit at 12 watts instead of 2.  A yacht carrying a compact Class A transponder like this will get seen a lot further away, and will also be able to input its navigation state and destination, just like the big boys.  And whereas we know that SRT actually builds these for OEM clients, we can probably expect to see it under other brand names soon.
   And what about SRT's promise for a small, inexpensive AIS receiver printed circuit board?  Well, I have no idea if Standard Horizon is using one in its new GX radio combos, but I'm pretty sure there's one inside Digital Yacht's new ANT200 seen below.  Yup, that's a complete true dual channel receiver just 4 inches in diameter, and it only costs $300 with it's own stubby VHF antenna.  Digital Yacht's got another interesting AIS receiver product I'll detail soon, and it sure looks like SRT is making good on its promises.



I've learned from ComNav that the expected MSRP for the Voyager X3 will be $2,999. So maybe I spoke too soon about SRT's promises coming true. In fact, you can already buy an ACR Nauticast2 Class A transponder for $2,999:

Then again, the price of SRT's original, and perfectly good, OEM Class B transponder has fallen nicely over time:

Posted by: Ben at December 14, 2009 3:06 PM | Reply

Ben: If we see retail discounts of ~20% on Comnav like we do on Furuno than $3,000 is still a pretty good starting price, about one third lower than the Furuno FA150.

But the Comnav is actually an inch *wider* than the Furuno and the "late 2010" date for N2K is ridiculous. Why bother, since anyone who wants one now will have to use 0183 directly (as there are no 0183-2000 bridges that support AIS at the moment)? I doubt that many who run 0183 wires now will pull them when the N2K firmware revision is released. (Though I guess maybe I would!)

But I do think the idea of putting N2K on a piece of "professional" gear is interesting, in that it acknowledges that recreational boaters are growing unhappy with the prospects (real or imagined) of second-class-citizen treatment of Class B AIS users.


Posted by: Adam at December 14, 2009 6:23 PM | Reply

Adam, The Furuno FA150 is actually a two piece system, with the black box FA1501 AIS transponder much larger than the FA1502 Monitor. That's not really clear on the web page, but it's illustrated in the install manual:

And an interesting link regarding SRT and expanding Class A mandates:

Posted by: Ben at December 14, 2009 7:06 PM | Reply

I think "transponder" is a misnomer for AIS equipment. The term was coined in Aviation for a radio that transmits a response when interrogated by radio from a ground based radar site. AIS does not wait for someone to ask it where it is, it just transmits and receives continuously. For that reason, I hold that "Transciever" is the proper term, and notice that most manufacturers seem to agree. Vendors are more sensitive to the language that customers might search for, and tend to use both terms in their literature.

Posted by: Sandy Daugherty at April 6, 2010 4:44 PM | Reply

We've been around this tree before, Sandy. I think you're right that AIS doesn't quite meet the definition of transponder because it's automatic. On the other hand, the time organizing scheme is interactive. Plus transceiver, while completely true, is too general.

At any rate, the USCG and other authorities use transponder, and that's good enough for me...

Posted by: Ben at April 6, 2010 4:52 PM | Reply

I called ComNaV today to verify that this update has happened. Not yet...

Is there such a thing as a Class A AIS that is NMEA 2000 capable?

Posted by: Howard at September 23, 2014 6:21 PM | Reply

Howard -

Take a look at the McMurdo Smartfind M5, a Class A AIS that uses NMEA 2000. See:

Unfortunately, it's not inexpensive (it retails for approximately $2,200 in Europe) and I don't know if it is for sale in the United States.

Posted by: Dan in reply to Howard at September 24, 2014 12:26 PM | Reply

Thanks Dan for the Link! It doesn't appear to be FCC approved..

Posted by: Howard at September 29, 2014 6:09 PM | Reply

I do see the McMurdo Class A AIS displayed at U.S. boat shows, so I think it's approved. The approval may be under AMEC, which actually manufacturers it.

Howard, ComNav told you that their Class A doesn't yet support NMEA 2000? That would be darn surprising as it's actually made by SRT which has numerous N2K AIS devices.

Posted by: Ben at September 30, 2014 9:38 AM | Reply

Yes Ben, I called ComNav directly and was told that it does NOT support NMEA2000.

I will search for the Amec, it is not under Mcmurdo or their parent company.

Posted by: Howard at September 30, 2014 9:15 PM | Reply

Milltech also sells the AMEC Class A in the U.S., and lists it with NMEA 2000 output:

But I also found further confirmation that the SRT-made Class A sold under ComNav, Em-Trak and other brands never got working N2K output:

Posted by: Ben in reply to Howard at September 30, 2014 9:35 PM | Reply

I have sent an email inquiry to Milltech. They are local to me. I am hoping they have put one in place or are willing to let me test it on a NMEA 2000 network. I have the rest of the week off to spend on boat projects.

Posted by: Howard at October 1, 2014 12:27 AM | Reply

I am interested in using a class A on a "pleasureboat" since I have seen how much reduced the range of class B transceivers is compared to class A even giving fault-free masttop antenna installations. Class B does not in my experience give more than 12nm while there seems to be almost no limit with class A. I have myself seen nearly 100nm on rare occasions.
I don't like the added power draw, though, and my main questions are:
- do I violate a law and can expect negative consequences if I fail to update the voyage-related data when I am supposed to or if I set this information to blank (if that is possible)?
- does a unit such as the AMEC take heading data from NMEA2000 or do I need to provide this via the separate sensor ports shown in the wiring diagram using NMEA0183? An will the unit work correctly when no heading data is available? (I think so because I have seen class A targets displayed perpendicular to a pier)

Posted by: Henning at October 1, 2014 12:43 PM | Reply

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