Date: Thu, 12 Apr 2001 
From: Bob Bruninga, WB4APR
To: TAPR APRS Special Interest Group <aprssig@lists.tapr.org>
Subject: TX-Cycle Recommendation?

> What is the recommended TX cycle (time between TX frames)?

I will not touch that with a 10 foot pole. <GRIN>

When we launched PCsat NO-44, the routine objective was for each
traveler or station needing satellite connectivity to get at least ONE
position/status packet via the bird per 12 hour period.  (On the NEXT pass
if the urgency is higher than routine).  With the terrestrial linked
global infrastructure this is completely sufficient for the mission.

The ISS experiment is not dedicated to APRS, but shared with other UI 
packet users worldwide.  For a position/status, I see no need for more
than  one success per pass or maybe 2 widely separated so as to hit those
both  before you and after you on the ground track.

Any station that has successfully seen his APRS POSIT/STATUS packet in the
downlink should cease transmitting it at that point.

On ISS, We hope that after the initial excitement, that things will settle
down into a healty routine where everyone gets their small one second
chance to be seen... and then lets someone else have  a go...  We want to
see schools with kids watching to have a good chance at success on every
pass. Define success as ONE PACKET and your chances go way up...

By encouraging everyone of us to stay low key, then this helps assure each
of us that there may be more bandiwidth available when WE do our own
little school or public demo..  If you are doing a demo, please include it
in your status so all can see.

de WB4APR, Bob