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[aprssig] Balloon DFing on APRS (DFS)

Bob Bruninga bruninga at usna.edu
Mon Mar 5 18:29:22 UTC 2012


> I believe Bob is planning to use the original directional DF, 
> not the omni-DFS for his balloon tracking. 

Lynn, good assumption.  Launch is not today (obviously) but now can be
Friday or the next week...

But I'd love to use OMNI-DFS since we should get plenty of signal only
reports and it would be ideal to see them as well.  But because we did not
anticipate balloon Signal Strengthing, the OMNI-DF technique only makes
meaningful plots for reasonable PHG values since the size of a OMNI-report
is based on the PHG plot.

Im racing to meet a travel deadline and will be out the rest of the week.
But Ill lay this at your feet... (if you want to consider it)...

Maybe we should look at extending DFS significantly for Balloons?  In fact,
I think I have allowed (in my code anyway), the extension of the HEIGHT byte
in PHG to extend beyond "9" (not sure if this is documented anywhere), but I
cannot remember if we let "A,B,C,D,E,F" be the next heights or we let it
just extend in the ASCII table above "9" as :;<=>.  Anyway, lets assume
ABCDE?

A = 10,240'
B = 20,480'
C = 40,960'
D = 81,920
E =163,840

Now, given that, then a DFS report can give some useful overlapping DFS
circles for Balloons.  If nothing else, we can make it special coding for
just this event, or some other way make it work for now using APRSISCE or
whatever other code wants to try this.

Bob, WB4APR




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