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[aprssig] info TM-D710

Bob Bruninga bruninga at usna.edu
Sun Feb 24 16:52:41 UTC 2008

> my TM-D710 in automobile and with my gps 
> sends the position gps when I am firm. 
> when trip, the position is rarely transmitted 
> and so the move is not seen on the map APRS 
> of UIview-32 but only distant positions 
> among them..

The D710 has a feature called proportional pathing.  This function keeps your position rate HIGH for local RF, but it reduces the length of the path for every other transmission.  This protects the network from high QRM at larger distances but lets you beacon at a rewasonably high rate locally so that people nearby can easily see updates.

At a distance, usually, people do not need to see your precise position every minute, but maybe only once every 4 minutes or so...

> My beacon is 0.5 minutes.  

This is too high for routine driving.  For toutine operations in most APRS areas in the world, the rate should be no higher than once every minute locally and propaply every few minutes at a distance.

That is the advantage of Proportional Pathing.  It lets you run a 1 minute update rate local simplex so that you can communicate well with other APRS stations nearby.  But only one packet every 2 minutes will go via the nearby digipeaters.  Then only one packet every 4 minutes will go via 2 hops.  

This gives you a high 1 minute local tracking rate, while reducing QRM on the network by an order of magnitude...

It is important to share the network with others by keeping high rates local.


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