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Re: [tracker2] airborne digi

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  • Keith VE7GDH
    James VE6SRV wrote... ... Sorry for the slow reply... been a bit hectic the last few days! ... There s nothing like having your antenna up 10,000 feet! Even
    Message 1 of 10 , Dec 26, 2009
      James VE6SRV wrote...

      > Hey Keith, Pete's callsign is KD0CVN-1

      Sorry for the slow reply... been a bit hectic the last few days!

      > It looks like you might have done some homework... From what I can
      > see, you are using a single hop path at most. As you have observed,
      > you can get into the APRS network from an airborne platform very
      > nicely.

      There's nothing like having your antenna up 10,000 feet! Even though I'm
      at ground level, I have pretty good success with one and two hop paths.
      With a T2, Pete could use profile switching based on altitude. Depending
      on terrain, he could use a standard two hop WIDE1-1,WIDE2-1 (or possibly
      WIDE2-2 instead) below a certain altitude, and either no path at all or
      a one hop WIDE2-1 above a certain altitude. He could also have a switch
      to manually force it to the two hop profile if there were occasions
      where it was deemed necessary... e.g. an area where the digis and IGates
      were really spread out and the mountains were protruding above the
      altitude where he normally switched to the one hop profile.

      One hop vs no hops... you only have to make it to an IGate for people
      tracking the plane via the APRS-IS. Where the IGates are close together,
      a plane could be heard direct by a number of IGates at any given time.
      Where they are spread out a bit more thinly, a one hop path would at
      least double his chances of making it to an IGate as long as there were
      some digis around the IGates.

      Pete KD0CVN had said...

      > I'd like to set up the digi function (mini awacs)...

      As several people mentioned, having a digi up at 10,000 wouldn't
      necessarily be a good thing, unless you were in any area where there
      were no digis. You could be hearing signals from a few hundred miles in
      each direction, perhaps taking in area of 30,000 to 200,000 square
      miles. In many areas, you would be propagating signals much further than
      the originator intended, and far outside their ALOHA circle. You could
      be forcing users using a sensible two hop path to be spreading their
      signals as far as if they had been using a seven hop path. Basically,
      except under special circumstances, a regular digi on 144.390 at 10,000
      feet would be a bad thing.

      73 es cul - Keith VE7GDH
      "I may be lost, but I know exactly where I am!"
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