Trueheading AIS-CTRX, Class B is shaping up

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

9 Responses

  1. tmaier says:

    The trueheading brochure indicates support for ITU-R M.493-9, which is the spec for “Digital selective-calling system for use in the maritime mobile service”. I imagine that this device is “bilingual” in that it can speak both AIS and DSC. The DSC spec defines a “Distress” message that can be both transmitted and received. It’s interesting to note that the Nobeltec software that is featured in the trueheading pdf began supporting NMEA DSC sentences in version 8.0.

  2. Ben Ellison Ben Ellison says:

    Thanks, Tom. I think every Class B transponder has to to listen to VHF 70 (DSC) as part of the “frequency agility” business:
    So it seems possible, but not definite, that the “Distress Message” is DSC. I’m sure we’ll find out soon.

  3. Russ says:

    “Dealer only” programming is a very poor idea. MMSI’s, boats, owners, etc. are not as static as you would think. For example when my Icom 502 had to be returned to Icom twice for replacement, if I could not have programmed it myself, I would have had to take a separate trip to the dealer each time to get it programmed. Dealer’s don’t like to provide free services after the sale, and customer’s don’t like to pay.
    Further, this probably means the manufacturer will provide no way to update the firmware. You can be very sure that any AIS B unit bought in the next year is going to need at least a couple of firmware upgrades as the problems are detected and the fixes issued.

  4. Ben Ellison Ben Ellison says:

    From a somewhat reticent (but generally correct) Panboid:
    “i’m delighted to see the marketplace coming alive
    with products in this space, however…..BSH may be honored by USCG for their approval purposes, but it’s completely irrelevant down at the FCC.
    just like any other device, their box will have to undergo type acceptance testing at the FCC lab. I spoke with Comar a few months ago and type acceptance was the one thing holding up their entrance. their unit was ready to go in Europe but you gotta have that FCC label or you’re in big trouble selling it in the US. and the FCC takes a very dim view of asking for forgiveness after having violated the rules.

  5. russell says:

    SmartRadio is making an AIS Transponder/Receiver which is user programable and they will sell direct right now, the price they quoted me was $676 including DHL shipping to the US. I am unsure about the legalities, they have Chinese CSS approval, but I am not sure what that means for operating it on a US yacht. This is the same company that makes the receivers sold by Milltech Marine. I was going to order one of these transponders, but decided to hold off and see the other options that show up in the next few months. But if someone wants one NOW and for a decent price, there is an option.

  6. Ben Ellison Ben Ellison says:

    I’d sure be careful about that transponder; I’m not at all sure that it meets the Class B spec. I’ve queried Milltech for more information, but it seems noteworthy that Milltech doesn’t sell it.

  7. russell says:

    With output power being only 3w on these units coming out soon does anyone have any idea of expected range? Class A traponders trasmit at 12.5w right? 3w is considerably less then that, I would love to know expected range in open ocean with a mast mounted antenna.

  8. The Class B specification has evaluated (in real-world tests) the range for 2 W output power to be more than 7 nm.
    This is, to my experience, around the double of the range at which a normal yacht is normally picked up by radar if any kind of a sea is running.

  9. Egenolf van Stein Callenfels says:

    Dear Panbo,
    I have used the Trueheading CTRX one year now on our 43 ft sailboat in and around the North Sea. It turned out to be very usefull, specifically crossing shipping lanes. It is an extremely reliable unit, with high sensitivity both for GPS and VHF. It is also very well “marinised” much better than some fancy Chinese boxes. I use it in combination with a SeaMe radar target enhancer.
    NB the central button on the CTRX is to suppress tranmission and it is not a distress button.
    By the way, all the best to Fred Pot, I know him from way back. I know he is against AIS-B but I dont agree with him.
    Kind regards,
    Egenolf van Stein Callenfels
    Dutch Offshore Cruising Association

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