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[aprssig] APRS vs. SPOT

Keith VE7GDH ve7gdh at rac.ca
Wed Sep 7 16:43:25 UTC 2011


Lynn KJ4ERJ wrote...

> Not even worth comparing nor discussing on an APRS sig, IMHO...

I thought it was an interesting question. While amateur radio has been
on the "leading edge" of communications a few times in the past, we
are being left behind when you look at things like SPOT and AIS.

SPOT has the advantage of the use of commercial satellites. There
have been a number of amateur satellites over the years. It wouldn't
stretch things too much to consider a constellation of half a dozen LEOs
in polar orbits running as APRS digis or even "store and forward" for
messaging. It all comes down to money and someone to take the bull
by the horns and design the system and start looking at ways of 
funding it. Perhaps the satellites could have some secondary function
on non-amateur frequencies that could be leased out to commercial
interests. However, you probably wouldn't get any reduced pricing
launches when there was commercial equipment on board.

You can go out into the boonies now and beacon every minute and
sometimes, you will be picked up by the ISS. A more intelligent
system would know when the satellites were there and only beacon
when there was something listening, or alternatively, the satellites
could send their own beacon to wake up the "trackers" so they
wouldn't waste batteries when there wasn't any coverage.

I mentioned AIS too. They have us beat hands down for packet collision
avoidance. They do have the advantage of not having to deal with digis...
just vessels beaconing their position / speed / course etc. They only
have to worry about time slotting out to their RF horizon, but they still
manage to have a system that can work with thousands of vessels within
earshot of each other.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"



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