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13253Re: [tracker2] T2-135 Digipeating Issues

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  • Keith VE7GDH
    Dec 2, 2011
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      Gil WB2UTI wrote...

      > I have a T2-135 system that I've had for a few years. It has
      > always worked pretty well. It is presently running as a fill-in
      > digi at my house (responding to WIDE1-1 and my call sign,
      > WB2UTI-1)

      First, fixed stations, let alone digis, should not use WIDE1-1
      anywhere in their own path. A one hop WIDE2-1 path should
      be used instead of the two hop WIDE1-1,WIDE2-1 that you
      are using now. There also shouldn't be a need for it to beacon
      as often as it is, and you seem to be sending your PHG in a
      separate transmission.

      Keep in mind that my comment about "beaconing often"
      could be caused by delayed packets going through a nearby
      digi. You could test that by using some time stamped
      beacons sent manually from the T2-135 and then checking
      on aprs.fi.

      2011-12-02 12:24:51 UTC:
      2011-12-02 12:26:13 UTC:

      > ...it had to have a radio/APRS beacon in it. I manage that with
      > a Kenwood D72 and an external antenna mounted on the cart...
      > I don't seem to be getting digipeated by my own home station
      > and most other digipeater stations are far enough away that I
      > don't usually get heard by them...
      > What is particularly frustrating is that if I hook up the Alinco
      > radio... and track myself... the display map shows every
      > beacon I sent and it traces my path perfectly. But if I go to
      > aprs.fi, I'm lucky to get maybe two position reports (out of
      > 25 - 30) for the same trip. So the radio seems to be
      > hearing and decoding me OK and passing that along to
      > APRSPoint, but more often than not, it's not digipeating
      > me (my path in the D72 is WB2UTI-1,WIDE1-1,WIDE2-1).
      > I have the home station set to beacon occasionally and aprs.fi
      > hears every one of those beacons, so I know that radio is
      > capable of hitting the nearest I-Gate.

      That would be a three hop path. Why not use a generic two
      hop WIDE1-1,WIDE2-1 in the D72, or even a one hop
      WIDE1-1 if the T2-135 is making it to an iGate in one hop
      as often as it would appear? By starting the path with
      WB2UTI-1, the D72 isn't going to be digipeated by
      anything else unless it is heard by WB2UTI-1, but you
      seem to be indicating that the T2-135 consistently hears
      the D72 but isn't digipeating it.

      Also, WIDE1-1 should never be used anywhere except at
      the beginning of a path.

      What is the TX delay on he T2-135? If it was too short, it
      could explain why the digipeated packets aren't being heard,
      but that doesn't seem to make sense as its own beacons are
      being heard, at least by another digi or an iGate, if not by
      the D72.

      > I'm running pretty much the default smart-beacon profile on the
      > D72 radio and the beacons are not more frequent than two minutes
      > or so at the shortest (so I don't think they're coming in too
      > frequently for the digipeater to respond). I only rarely get
      > the acknowledging two tones in the radio to indicate that a
      > digipeater has heard and repeated me and when I do, it's
      > occasionally when some distant digipeater has heard me.

      Any chance that the amplifier is causing a problem? Does
      it use an antenna relay, or does it use something like PIN
      diodes? Bring the D72 into the shack and test it there where
      you can watch the T2-135 to see it transmit right after a
      D72 beacon, and listen for the "digipeated" confirmation
      on the D72.

      > I do hear and decode other stations on my D72 so I think that's
      > working OK. I do get the acknowledgement when I'm close to
      > home, but even then, those beacons don't necessarily show up on
      > aprs.fi (packet collisions on the output of my home station?).

      Break it down into sections. Change the T2-135 over to a one
      hop WIDE2-1 and test that most of the beacons are making it to
      an iGate.

      Also try a two hop WIDE1-1,WIDE2-1 from the D72.

      > As for settings on the T2, I have WIDE1-1 enabled for
      > digipeating as well as digipeating on my call in both profiles
      > (which are identical).

      Do you have profile switching enabled? If so, for what parameters?

      Then check and see if the T2-135 decodes most of the beacons
      from the D72, and see if the D72 can consistently decode the

      Finally, see if the T2-135 consistently digipeats the D72.
      Listen with another radio. Distorted tones or short transmit
      delays might be apparent by ear.


      One thing seems definite. The D72 isn't making it to an iGate
      very often, and in spite of my thoughts above, it seems to
      need a three hop path.

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