[amsat-bb] 60 Grid Squares for APRStt satellite?

Robert Bruninga bruninga at usna.edu
Sat Jan 24 22:25:01 UTC 2015


The next APRS satellite will have a DTMF uplink for people to get into the
global APRS system with any old HT, not just the expensive APRS integrated
radios.  THey will hear a voice QSL in return.

I want to indicate all grid squares as 4 decimal digits  for this
application to keep it short.    Instead of FN19 for my grid, it can be
nn19 where nn translates on the spacecraft to "FN".  I just counted and all
of the countries and locations that have any nominal ham radio population
appear to fit in under 60 major grids.  We just need a mapping on the
satellite to map these 60 in to the two digit nn number.

It would be nice if there was an easy encoding method so that an entire 60
deep table is not needed, but simply an algorithm.  If any such system
exists let me know.

As it is, I see exactlyl TEN major country areas, and so the first digit
could simply indicate the area.  And each of those areas have 0 or less
smaller populous grids.  So it should work out well.

Of course no one is excluded.  Its just the 99.99% of hams that live in
these 60 grid squares can encode their grid in 4 digits.  Those anywhere
else in the world will take 6 DTMF digits for their posi (2 each to spell
the two letters)..

For info about APRStt (Touchtone) see http://aprs.org/aprstt.html

So, do I have to create and figure out a cute encoding method for this top
60 (to 99) list, or does something like this already exist?

Bob, Wb4APR


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