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[aprssig] info for TM-D710E in car

Bob Bruninga bruninga at usna.edu
Sun Jan 13 16:38:54 UTC 2008


> My... D710E is connected with GPS. 
> When we are in movement, it transmits [OK]
> for the first thirty minutes...
> then it lengthens the times in way random. 

This is the APRS standard for decay position reporting. 

Since the original APRS, this is the preferred way of transmitting APRS.  If data is changing, then it is transmitted frequently.  But if it is the same identical position, then the transmission rate decays to a longer value to reduce QRM on the network.

This concept of fresh data transmitted frequently and old-unchanging data less frequenctly was fudnamental to the design of APRS.  When all stations do it, then the channel can support an order of magnitude more stations on the same channel. Too many follow-on projects ignoed this fundamental aspect of APRS.

> so my position is not correct in the UI-View  map.

It should be.  The delay only happens if your posiion is not moving or changing.  If you are moving, then there is no decay.

Bob, Wb4APR

 




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