SV: [aprssig] Another kind of SmartBeaconing?

Rikard Sohlberg rikard.sohlberg at
Sat Aug 25 17:12:01 CDT 2007

Hmm.. Interesting idea... This would also lend itself to plane-to-plane
position updates... Hmmm... 
Must think about this idea. 
Maybe you have heard of a device called Flarm? It's become very popular in
gliding circles (no pun intended...), at least in Europe. Not sure about the
US. It's an anti-collision warning device (I believe the heavy iron use
something called ACARS, correct me here if I'm wrong..). The device
calculates a speed and energy vector from an onboard GPS and transmits it.
Also listens in for similar transmissions from nearby gliders. If the
vectors interfere with each other, the device triggers an alarm and a rough
direction in a small panel in the cockpit. I'm not exactly sure where the
thing sends, I was under the impression it was on the 2.4 GHz ISM band, but
someone said it was in some license free 800 MHz slot. As the power is very
low, unfortunately, it's no good for 'to-the-ground' transmissions of
positions. Haven't flown one myself, but I'm considering getting one for
next season.

Thanks for your ideas!

73 de SM0JWX/Rikard

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-----Ursprungligt meddelande-----
Från: aprssig-bounces at [mailto:aprssig-bounces at]
För Robert Bruninga
Skickat: den 22 augusti 2007 16:14
Till: 'TAPR APRS Mailing List'
Kopia: 'Mikael Engström'
Ämne: RE: [aprssig] Another kind of SmartBeaconing?

> ... We have tried SmartBeaconing and fixed 
> interval beacons. Neither one serves a glider 
> particularly well. A glider... typically circles 
> in a thermal... and then flies in a straight line 
> .... What is needed, though is fast updating at 
> the end of the track. 

Proportional Pathing was designed for this kind of
high-rate-close-in, and lower-rates-at-longer-paths, but this
will not work for Gliders who have line-of-sight to everywhere,
and hops are usually not needed.

But applying this same algorithm to TX POWER would work.  That
is, a 30 second rate at 1 milliwatt, every other one at 10
milliwatts, every other one of those at 100 mw and every other
one of those at 1 watt.

You would get high tracking rates when the planes are close, but
minimum QRM for the less often-and-further away higher power

Bob, Wb4aPR

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