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[aprssig] Tiny Tracker III loading?

Robert Bruninga bruninga at usna.edu
Mon Jan 22 22:01:17 UTC 2007


Many APRS lessons here:

I just happened to listen to 144.39 today at work, and was
surprised to hear a very high rate packet source with a very
long TXD.  Turns out it was a TInyTracker III that was tying up
the channel almost 50% of all time.  Here were the problems, all
further compounding the problem:

1) the TXD was too long by about a factor of 10.  It was more
than a full 1 second long when it should be as short as 100ms or
so.  

2) It was using a 3 hop path in the middle of the highest
density APRS system (outside of LA).  Only  2 Hops are
recommended in this area.

3) The smart algorithm was too tight.  It generated 30+ packets
just driving the first 0.5 mile from his work QTH in under 3
minutes.

I would never have noticed this without listening to the audio.
His packets were coming so fast, that the digipeaters were
stepping all over each other and so not all that much got out.
Certainly not enough to see all 30 posits in 3 minutes over 0.5
mile. (But I was direct so I saw it just fine).

Anyway, we need to be very vigilant about improper settings that
might kill the network.  Sometimes the worse they are, the less
they can be seen by just looking at the map or looking at
successful packets.  Sometimes you have to just listen to the
audio to see what is happening on the net.

LISTEN everynow and then.  Fix what is broke.

Bob, WB4APR





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