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  1. #61
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    Jun 2009
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    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by RichardS View Post

    ...

    So, on that point GHA, please tell us all why you believe that an AIS transponder does not receive and transmit AIS data.

    Richard
    I don't think that he, or anyone else, ever said any such thing here... It is certainly true that they are often referred to as "transponders", but it is not really the correct term. A "transponder" is a device which receives a signal and transmits a response to it - that's where the "pon" in the name comes from. AIS does not work that way - the transmit and receive sides are independent of each other with the small qualification that the transmit side does take notice of the timing of received packets in order to reduce the probability of collisions between multiple transmitters. The transmit side does not wait for an incoming packet before transmitting anything - in the way that an active radar reflector does, for example.

  2. #62
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    Nov 2009
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    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by awol View Post
    [pedant] An AIS device that receives and transmits is NOT a "transponder" - you ignorant lot![/pedant]
    Quote Originally Posted by maby View Post
    I don't think that he, or anyone else, ever said any such thing here....
    All I said was that a device which receives and transmits is a transponder ..... which is exactly the same as saying that a transponder receives and transmits AIS data, although you need to go back to post #30, quoted above, to follow it through.

    Awol and GHA will simply not accept this statement of fact.

    Richard

  3. #63
    Join Date
    May 2007
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    38,114

    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by awol View Post
    Which despite RichardS's assertion does not describe an AIS transceiver as presently used by ships and other craft.
    Pedantic, indeed yes, but if words are used wrongly, credibility in the message is diminished as is that of the sender. Arguing that "we all know exactly what we mean" is just another of the dumbing down, anti-expert attitudes that is only too prevalent in present times.
    SRT are the experts IMHO, they call class B in particular a 'transponder'.
    I think the transmission is responding to the 'population' of class A emitters as a whole, is a legitimate view of what is going on in general.
    AIUI, class b devices can also be polled by some class A devices, which makes them transponders by most definitions.


    You can beat yourself up too much with defintions of technical terms.

  4. #64
    Join Date
    May 2007
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    38,114

    Default Re: AIS - essential kit these days for channel crossing?

    I guess this AIS receiver is a transponder, since it squirts the data onto wifi?
    https://www.quark-elec.com/product/q...-gps-receiver/

    Looks like a top toy for £100. AIS on your phone?
    Anyone got one?

  5. #65
    Join Date
    Dec 2003
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    5,541

    Default Re: AIS - essential kit these days for channel crossing?


  6. #66
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    Jun 2009
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    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by RichardS View Post
    All I said was that a device which receives and transmits is a transponder ..... ...


    Richard
    That is certainly not true! I have a walkie-talkie on the table next to me as I type this - it both transmits and receives, but it is a "transceiver", not a "transponder" - it does not automatically transmit anything in response to receiving something. Trust me on this - I'm a radio engineer...

  7. #67
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    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by maby View Post
    That is certainly not true! I have a walkie-talkie on the table next to me as I type this - it both transmits and receives, but it is a "transceiver", not a "transponder" - it does not automatically transmit anything in response to receiving something. Trust me on this - I'm a radio engineer...
    Jeez. This discussion is getting more like kindergarten.

    We are discussing AIS devices (see thread title if you need confirmation) and I have repeatedly said that an AIS device, like the ones which are being discussed in this thread, which receives and transmits includes both a transponder/transceiver depending upon your position on this discussion.

    Please go back to post #55 if you really need the detailed explanation, or simply refer to the second part of my quoted statement which you understandably deleted.

    Richard

  8. #68
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    Nov 2009
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    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by dom View Post
    Indeed .... but in that thread both "transponder" and "transceiver" were used interchangeably and no-one batted an eyelid 'cos we all knew exactly what was meant.

    Richard

  9. #69
    Join Date
    Sep 2018
    Location
    Hayling Island
    Posts
    15

    Default Re: AIS - essential kit these days for channel crossing?

    Interesting comments,

    I've made a number of crossing over the years without AIS or Radar and poor visibility has always worried me as it can come down out of nowhere.
    Last year I bit the bullet and bought a DSC with AIS built in it had it's own spiliter so basically plug and play and i'm delighted with it.
    On a night crossing mid channel 2 large cruise ships came up crossing S to N. AIS allowed me to see their exact course and CPA which was very reassuring.
    Total cost about £350 and well worth it for peace of mind.

  10. #70
    Join Date
    Oct 2002
    Location
    Plymouth
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    8,579

    Default Re: AIS - essential kit these days for channel crossing?

    Quote Originally Posted by Sadlerfin View Post
    ...

    Last year I bit the bullet and bought a DSC with AIS built in it had it's own spiliter so basically plug and play and i'm delighted with it.
    ...
    Good to know.
    Do you find the small display adequate, or does it feed into your plotter?

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