Announcing the Simrad RS40-B, The First VHF Radio with AIS Transmit/Receive Capability

22 Responses

  1. Ben Ellison Ben Ellison says:

    Cool! I’ve known that many boaters want a combination VHF radio and Class B AIS since Standard Horizon announced the GX6500 in 2016 (and sadly never shipped):

    https://www.panbo.com/standard-horizon-gx6500-a-loaded-vhf-radio-also-integrated-with-class-b-ais/

    But I have questions. Like does the Simrad RS40-B (as known as the B&G V60-B) work with a single antenna for VHF and AIS? Hopefully more details will be available soon.

  2. Timo says:

    Surprisingly Simrad has withdrawn all references to the RS-40B from their web page only days after publishing. Same for B&G. Let’s hope Simrad did their homework given the issues Standard Horizon had with their similar product launch some years ago.

    • Ben Ellison Ben Ellison says:

      That’s quite odd. In fact, I received a PDF copy of the B&G V60/V60-B User Guide last night and the new Class B model looks very much ready to go, with references to regulatory approvals all over the world.

  3. Ben Ellison Ben Ellison says:

    Incidentally, Ben Stein found evidence of who’s helping Navico to build this radio series:

    https://fccid.io/RAYVHFRS40/Test-Report/Test-Report-IEC-4069960

    Apparently Hytera is involved with the new Raymarine VHF radios too and, by the way, I don’t think that any of the major navigation electronics brands build their own radios or AIS transceivers.

  4. Anonymous says:

    Do we know which class B they are using – SOTDMA or CSTDMA?

  5. Geoff says:

    Do we know if it’sSOTDMA or CSTDMA?

  6. Bill Barnum says:

    Ben,
    Im sure you probably know this but for those who dont, Marine VHF channels in the US rx/tx 156-157 MHZ where as AIS receve only class A(rx) and class B transmit(tx) are 162 MHZ. A 159 MHz antenna is typically chosen for Class A. A “splitter” swtich enables selection between two antennas. Presumably this description merely allows the user to AIS transceiver mode OR radio telephone operations but not both simultaneously. I suspect the radio uses independent transceivers but even so, I dont see how simultaneous over a single antenna is possible without disruption. Regardless, my understanding is that optimal performance would best be achieved by using a 157 MHz antenna for communications and a 162 MHz for AIS.

    • Ben Ellison Ben Ellison says:

      Thanks, Bill. You are correct that optimal VHF and AIS antennas are slightly different, but I’m not sure what you mean by “AIS receive only class A(rx).” Class A and Class B — which now comes in two types, CS and SO — all transmit alternately on the two AIS frequencies clustered around 162 MHz and listen to both when not transmitting. AIS receive-only radios have no Class designation or regulation. Lots of solid info here:

      https://www.navcen.uscg.gov/?pageName=mtvhf

      The Navico combined VHF and Class B AIS has two antenna ports on the back and will ideally have both AIS and VHF antennas. But there are certainly lots of boats out there, including mine, that use an active antenna splitter so that one antenna can work for both VHF and AIS. Of course, AIS info cannot be received when you’re transmitting on VHF, but they seem to work pretty well otherwise.

      https://www2.vespermarine.com/antennas-splitters/antenna-splitter-sp160

      • Jorgen C says:

        As Ben correctly points out now two versions of AIS class B. The new one, SO or SODTMA, has a significant better method and wattage for making it self being noticed by other AIS-targets. To me it is a complete spoiler – if really true – that Navico have saved a handful of dollar and not gone for the new for superiour standard (the SODTMA standard). This makes the marketing saying that the RS40 is the perfect upgrade sound complete hollow – close to being misleading. The truth is that with the new addition to the B-class, nobody having a boat moving more than 3 knots, in perfect weather, would buy a class-B transponder without SODTMA in todays market.

        • Ben Ellison Ben Ellison says:

          Hi Jorgen, I agree that Class B SO (also called B+) is better than the original CS, but I think that you’re confused about the transmission rates, and thus CS is not as bad as you think. Specifically, from 3 to 14 knots both CS and SO transmit dynamic date every 30 seconds, as well explained here:

          https://digitalyacht.net/2018/11/26/class-b-sotdma/

          But I also think I may understand the source of confusion, which is a U.S. NavCen “Meters Per Knots @ Each AIS Class Reporting Rate” table that’s still online and that I published here:

          https://www.panbo.com/sotdma-class-b-ais-the-new-middle-way/

          I’m amazed that no one ever noticed, myself very much included, but I’m pretty sure that the numbers for B/SO at 3 and 4 knots are wrong. And I’m going to double-check that hypothesis right now 😉

  7. Mark says:

    No mention of a GPS antenna being included. Is that a TNC connector on the rear, or does this radio have an internal GPS? I would expect this radio to require 3 antennas: VHF, AIS, and GPS.

    • Ben Ellison Ben Ellison says:

      Mark, it has an integrated GPS receiver and antenna, but an optional passive GPS antenna is supposedly available if the radio’s install position doesn’t have a decent sky view. I don’t yet see the antenna listed as an accessory but I imagine nearly any passive GPS antenna would work. I also don’t yet see the manual posted, which is where I confirmed this information.

  8. William says:

    My curiosity is killing me, what ever happened to the Standard Horizon radio that did both? Was there ever an answer given as to what happened, or are they too embarrassed to own up??

    Also, as someone asked, yes, you can use a single antenna to transmit and receive from multiple radios at the same time. If you want to know more at the topic, research “antenna duplexer”. Catch is they have to be on different frequencies.

    • Ben Ellison Ben Ellison says:

      William, to my knowledge Standard Horizon has never explained what’s keeping the GX6500 from shipping. In fact, they listed it as a new product in their 2017 catalog, and then again in their 2018 catalog, and yet again in 2019! I believe it’s safe to assume that the radio has not been fun for the SH salespeople who field the boat show questions.

      Isn’t duplex irrelevant for marine VHF (and AIS) because there’s only one duplex marine channel (#20), at least in the U.S.?

      https://www.navcen.uscg.gov/?pageName=mtvhf

      • William says:

        All the “public correspondent” channels are duplex, 24-28. Going back to the days when you could get an operator to place a call for you through the VHF.
        I was referring more to Bills question about transmitting and receiving simultaneously on one antenna.
        This is most commonly done on ham radio repeaters. The repeter setup is able to listen to your transmission and simultaneously rebroadcast it on a different frequency, and at higher power, using only one antenna. These types of duplexers are normally a wave guide filter that only allows a certain frequency above or below a point to pass. This protects the sensative receiver from the power of the transmitter.
        Technically the AIS splitters are duplexers because there are allowing multiple transceivers to use one antenna. However, I don’t believe any of them allow simultaneous TX and RX. I’ve never actually called any of the manufacturers and asked, but it’s my understanding that it is an either or situation and one transceiver is disconnected for protection from high power RF, while the other is transmitting.

  9. Bill Barnum says:

    Hehe… Thanks Ben. To clarify… I dont have a complete and thorough understanding of AIS, the link provided is greatly appreciated, and I have some homework to do.

  1. February 9, 2020

    […] Simrad RS40-B — and the B&G V60-B from its Navico sibling — was announced in June of 2019 with an $1,100 list price. This full featured radio can support up to two wireless handhelds and […]

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