[aprssig] Suggestion for APRS over Satellite

Stephen H. Smith wa8lmf2 at aol.com
Tue Apr 22 03:42:42 EDT 2008

Hans Johnson wrote:
> Hi All,
> I've been toying around with the idea of building some equipment for 
> extreme remote telemetry stuff to be done over satellite.  (Similar to 
> Bob's project in Mongolia).
> Anyhow, one of the things that would be extremely useful is if the 
> satellite could (occasionally) include its current orbital data in the 
> beacon packet, something like a condensed version of the Two Line 
> Element and a CRC.  Using this information, it could then power down 
> the radio until the next useful satellite pass.  This would 
> drastically reduce the power requirements for a remote site.  Also, 
> things like asatlogger and what not could use the information to 
> update their pass predictions automatically.

Won't the remote device then need to have fairly hefty computing power 
to crunch the orbital elements into a useful AOS/LOS prediction for the 
particular location the device is located at?  

I would guess that the power consumption of a controller with enough 
horsepower to do this would exceed the total power consumption of just 
having a much simpler dumber device power up the radio for a few seconds 
every 5 or 10 mins if the transmit bursts are really short. 

Not to mention you will also need to power a receiver that won't be 
needed with a "dumber" device, and a real-time clock to wake up the 
controller/transmitter at the appropriate times.    


Stephen H. Smith    wa8lmf (at) aol.com
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