[aprssig] KC2TUA/KC2UFG Ballon QRM

Robert Bruninga bruninga at usna.edu
Sun Mar 22 11:23:34 EDT 2009


> This multi-hop path means every digipeater within 
> 300 miles or more will be banging the network every 
> minute.... Come on guys, really...a packet every 
> minute at 30,000 ft with mutli-hop path!

Actually, I hear your frustration, but if I can offer some
mitigation... it shouldn't be that bad.  

Yes, each digi will put out one packet once a minute from the
balloon.  But that is no different than any other mobile driving
around at a one minute rate.   Basically it has added one new
mobile into the local area of each such digipeater for the
duration of the flight (probably about 3 hours or so).  This
should not be that much of a problem in each of those local
areas...

As to its being multi-hop.  That too should not be a problem in
the APRS WIDEn-N system, since each digipeater under the New-N
Paradigm will digipeat the packet once and only once no matter
how many additional copies it hears.

One minute might seem excessive, but then the Balloon might be
going 100MPH or more when it hits the jet stream, and the owners
reallly do have to hurry to get to the end point and stay within
speed limits, and balloons do change course at different
altitudes.  AND when the balloon breaks, the path down may be at
thousands of feet per minute.  SO I do not object to these
typical 3 hour missions at 1 minute rates...

The reason for the multi-hops is for when the balloon lands on
the ground and the serach team might need to be lucky to find
it, and it might go much further (at 100 MPH) than they can get
to before it hits the ground.  So the 2 hops helps them in the
final search (though it does no damage at altitude as noted in
the above paragraph).

I hope that helps...

Bob, Wb4APR





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