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[amsat-bb] HT uplink test via ISS?



SAREX list:  (I posted this incorrectly on the AMSAT-BB).
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I would like to propose an ISS experiment, where we dedicate the overnight
time of 22 May in the USA as an HT uplink test via the ISS digipeater?
The collective objective is to test the viability of HT QRP packet uplinks
under controlled conditions:

Test period:    Midnight local time to 8 AM local time 22 May
Test stations:  HT's (or equivalent) on omni antennas, 5W power
Test rate:      One packet every 1 minute

The objective is the collective throughput, not individual packets.  So if
you set up in accordance with the test criteria you ARE A SUCCESSFUL
PARTICIPANT.  If you got in, we got it.  If you did not, but your station
was properly configured, then please submit a report including your sky
view and any ideas why you might not have gotten in.  This is important
data.

Although we are focused on QRP uplinks, we do not want anyone to feel
excluded.  If higher power stations continue to operate, we ask that they
operate at a reduced duty cycle equivalent to their higher power:

  5W Omni every 1 minute  <== the objective
 10W Omni every 2 minutes
 25W Omni every 3 minutes
 50W Omni every 4 minutes
100W Omni every 6 minutes

In any case, we would ask that all packets include their station's test
conditions such as "5w omni every 1 min", or "5W beam north evy 2 min"
or "5W omni in trees" or "1W omni on hill"

An ALOHA channel like the ISS with blind transmitters can probably support
about 120 stations per pass.  The way to achieve this is for everyone to
transmit LESS OFTEN so that there are fewer collisions.  Just set your rig
to the recommended TRANSMIT RATE, go to bed, and lets see how we did in
the morning.

If we still have too many people on the uplink, we may try the test again
later with the 5W stations at once every 2 minutes which I think is
probably closer to the optimum rate given the number of people that will
be trying...

Depending on the success of this test, we might then turn it around for an
HT MESSAGE DELIVERY TEST at some later time.  In this test we will have a
few dedicated uplink stations seeing if they can deliver messages to X
number of HT's with STOCK RUBBER DUCKS on receive.  Think of these tests
as emergency preparedness tests...  

If anyone knows of any problems with this proposal for 22 May, please
speak up...  I chose that date when most of us are asleep during the
passes over the USA...

de WB4APR@amsat.org, Bob

ISS-APRS FAQ:       http://web.usna.navy.mil/~bruninga/iss-faq.html
PCsat Design        http://web.usna.navy.mil/~bruninga/pcsat.html
CUBESAT Designs     http://web.usna.navy.mil/~bruninga/cubesat.html
APRS LIVE pages     http://web.usna.navy.mil/~bruninga/aprs.html
APRS SATELLITES     http://web.usna.navy.mil/~bruninga/astars.html

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