[aprssig] TM-D710 APRS Parameters

Robert Bruninga bruninga at usna.edu
Thu Jan 31 12:14:24 EST 2008

> Here is my setup in the D710:
> Method                Auto
> Initial Interval      3
> Decay Algorithm       off
> Proportional Pathing  on
> Type                  New-N Paradigm
> Total Hops            2
> Speed Sensor Stopped  1
> Speed Sensor Moving   3
> With the D710 I get a lot of updates, probably 
> twice as many as I did with the TinyTrack 3, 
> many times a lot more often than the 3 minutes 
> Initial Interval.  Is there a document 
> available that explains how the D710 uses the 
> above parameters?

Here is my understanding of how it should then work:

1) Proportional pathing was designed to give good update rates
locally, while reducing overall channel QRM in the larger area
by an order of magnitude as follows.  Because of this improved
channel efficiency, setting the initial interval to 2 minutes or
even 1 minute for road travelers is the expected norm.   It does
this by:

   A. sends every other packet DIRECT only 
   B. Every other packet goes 1 Hop
   C. Every other one of those (4th) packet goes two hops

2) Decay will double the period if not moving.  This further
cuts the QRM for non-moving vehicles, while providing
reliability and continuity of tracking.

So I woiuld certainly set Decay to ON, unless you are doing
something special where you want to keep a high rate even for a
non moving vehicle.  The only time I use DECAY oFF, is when I am
parked and using the radio for the ISS or APRS satellite.  Then
I want it to stay at the 1 mminute constant rate.

Bob, Wb4APR

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