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Digital PMR446

  • 17-02-2009 1:16am
    #1
    towel401
    Closed Accounts Posts: 2,917 ✭✭✭


    anyone here used it? hows the range compared to regular pmr?

    for now there seems to be only a few radios being manufactured that support it. the only one i can really find is the icom one. is it an open standard and is the specification available to anyone? like the protocol they use and all that good stuff.

    do you still even have to select a channel or does it automatically select the best channels to use and broadcasts to all the people on the same "common id"?


Comments

  • #2
    watty
    Registered Users, Registered Users 2 Posts: 32,417 ✭✭✭✭watty


    towel401 wrote: »
    anyone here used it? hows the range compared to regular pmr?

    Poor.
    DIGITAL PMR 446 FEATURES
    The IC-4029SDR utilizes 4FSK/FDMA modulation and 6.25kHz digital narrow channel spacing, which is half the channel spacing of the existing analogue PMR 446 system. This way, the 100kHz band width allocated for digital PMR 446 is efficiently divided into 16 channels, or twice the current analogue voice channel capacity making this product incredibly spectrum efficient.
    http://www.icomuk.co.uk/categoryRender.asp?categoryID=3510&cCID=6157

    Icom also promote Dstar digital Audio for Amateur repeaters. It's an old, poor quality codec by modern standards. DStar is an "open protocol" but no-one else bothers making gear. Waste of money and repeater spectrum IMO as it is no better in quality and range than FM.
    http://en.wikipedia.org/wiki/D-STAR

    The Digital pmr446 model also supports the regular pmr446 narrowband FM mode.

    It's a very expensive radio with little advantage compared with a €30 pair. Released in Sept 2008.

    The 16 digital channels are on top of the existing 8 analogue channels. These radios have been approved in UK, but even if CE marked may not be legal here.

    Watch for CE(!) or CE /!\ on gadgets. That means not legal in every EU country.
    See also
    http://www.uhfcb.org/viewtopic.php?f=7&t=52

    Like DStar, this is another marketing Gimmick by Icom. No-one else makes them. If you turn down squelch, FM does have better range. SSB better still x2 at least of course. Slow digital data such as PSK31 will work better again, but at 446MHz, very often the limit is not power or signal type but buildings and terrain. On a pair of hilltops you may get 20km range with PMR446!


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