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[aprssig] Proper deviation levels

Robert Bruninga bruninga at usna.edu
Tue Nov 28 04:30:04 UTC 2006


> ...     Theoretically the high tone could be deviated 
> a full 5 KHz but there will then be no margin for 
> transmitter or receiver frequency  error if the 
> receiver has a narrow passband.   One is much better 
> off slightly under-deviated in order to 
> tolerate frequency error at either end.

And this is ESPECIALLY true when working the APRS Satellites
since they add +/- 3 KHz of frequency error due to Doppler.
Some of these wide-splattering signals we hear all the time on
144.39 would never make it into ARISS or PCSAT's except at the
center of the pass.

By the way, the ISS is back on the air with APRS digipeating
finally after being off for 90 days...   Oops, I just checked it
and the last packet is now 24 hours old... I guess it may be off
again?

Bob, WB4APR

> 
> 
> --
> 
> Stephen H. Smith    wa8lmf (at) aol.com
> EchoLink Node:      14400    [Think bottom of the 2M band]
> Home Page:          http://wa8lmf.com  --OR--
http://wa8lmf.net
> 
> NEW!   TNC Test CD
>   http://wa8lmf.net/TNCtest
> 
> JavAPRS Filter Port 14580 Guide
>   http://wa8lmf.net/aprs/JAVaprsFilters.htm
> 
> "APRS 101"  Explanation of APRS Path Selection & Digipeating
>   http://wa8lmf.net/DigiPaths
> 
> Updated "Rev G" APRS            http://wa8lmf.net/aprs
> Symbols Set for UI-View,
> UIpoint and APRSplus:
> 
> 
> 
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