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[aprssig] Telemetry definition messages

Robert Bruninga bruninga at usna.edu
Sat Mar 3 18:00:01 UTC 2007


> I tried to find how often should be sent telemetry definition 
> packets. 

APRS has 3 network time standards for normal Human Ops:

- REGIONAL:           refreshed within 30 minutes
- LOCAL/EVENT/DIRECT: refreshed in 10 minutes 
- Not-Active:         >80 minutes is not active.

These are the standard user expectations for valid, meaningful
changing data.  Telemetry is usually  a more routine, permanent
and long term type of system, so maybe it needs some
consideration.  Some telemetry is for long term, and others for
short term.

If the Telemetry is watchign the battery of special tracker in a
race car, then once every 10 minutes of data seems appropriate,
and refreshing the equations once every 30 minutes makes sense
to me.

If the telemetry is watching river levels, then a once every 30
minute data rate and a once every 2 hours refresh of the
equations might be appropriate DURING WEATHER ALERTS.   But if
it is watching something changine over longer periods, then I
woiuld do the equations once a day...

> opinion, the best way would be special query to get them at 
> request. But, there is no such query in the APRS
specification.

No, but a standard STATION Query to such a telemetry station
would rightly not only respond with its position packet, but
also its definition packets.  Because someone making a query,
clearly is a new station on the air, and needs both.

Bob, Wb4APR

> My tests with Deluxe are under AB9FX-8 callsign (all tlm data
without 
> special meaning, just testing, except A2 - internal voltage) 
>
http://www.findu.com/cgi-bin/raw.cgi?call=AB9FX-8&start=24&lengt
h=24
> AB9FX-8>APFOA0,WIDE1-1,WIDE2-2,qAO,AB9FX::AB9FX-8 
> :PARM.,,I,T,F,,,,,,,,
> AB9FX-8>APFOA0,WIDE1-1,WIDE2-2,qAO,AB9FX::AB9FX-8 
> :UNIT.LUX,V,A,DEG,HZ,,,,,,,,
> AB9FX-8>APFOA0,WIDE1-1,WIDE2-2,qAO,AB9FX::AB9FX-8 
> :EQNS.0,1.9255,0,0,0.1,0,0,1,0,0,1,0,0,1,0
> AB9FX-8>APFOA0,WIDE1-1,WIDE2-2,qAO,AB9FX:T#013,048,047,049,051
,053,00000000Test
> Screenshots of Radek's project http://sq2foa.republika.pl/ 
> (link - APRS 
> Deluxe)
> There is also a link to download project simulator running 
> under Windows
> http://sq2foa.republika.pl/deluxe_win.zip
> After opening this program all navigation is available with 
> arrows, Enter 
> and Esc. Telemetry monitor window by Esc from main view. 
> Example packets 
> could be changed in the 'wynik.txt' file.
> 73!
> Andy AB9FX
> 
> 
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> 





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