[aprssig] timeslotting on HF ? was > 15. APRS trackers on 10m (Robert Bruninga)
david at rushtone.com
Mon Nov 28 09:02:07 CST 2005
How about a VERY simple time-slot algorithm... such as the last letter of
your callsign indicates the minute past the hour or half hour within which
you're allowed to transmit? Calls ending with A could transmit during
hh:00:00-hh:00:59 and hh:30:00-hh:30:59, calls ending with B could transmit
in hh:01:00-hh:01:59 and hh:31:00-hh:31:59, and so on. The last four
minutes of each hour or half hour could be reserved for something special,
or simply a free-for-all.
Each user would have two one-minute slots per hour to work with. Such a
long slot accommodates manual timeslot-operation if necessary, and makes it
easier to keep track of time, especially for small, PIC-based trackers that
have very limited code space.
Within one's appropriate minute, users could pick a random time to transmit
(or sub-timeslot within a local area if multiple regular share the same
As far as I know, this should work equally well for most international
callsign patterns, but I could be wrong. Callsigns ending with a digit
would use the last-most letter in the callsign, maybe?
I first thought of an even simpler algorithm, where the (first) digit in
the callsign aligns with the last digit of the current minute, but then
realized that most callsigns in a given area would end up with the same
timeslot (at least the way calls here in the US are assigned).
Just thinking out loud, and knowing that simple is often a good thing...
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