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PCsat death spiral..



Now after a week, we are still not able to get PCsat into positive power
budget.  We ask all users to not digipeat any packets via PCsat.  We are
trying to keep DIGI turned off, but are not successful most of the time.

In a week, PCsat has gone through 15 deep discharges a day for a total
over over 100 deep discharges on the batteries.  This is killing it unless
we are successful soon.  Command stations throughtout the Southern
Hemisphere continents are trying their best (That is where PCsat currently
just enters the sun and it the only place where a "low power" command will
have any chance of recovering PCsat.)

You can grieve with us by watching the telemetry counter.  At one
telemetry packet per minute, you will be able to see if and when we are
successful by seeing if the T# counter ever gets above 100 ( a full 100
minute orbit without RESET)...  Since, PCsat is resetting (running the
batteries dead) on every eclipse the T# counter always starts at 1 when it
enters the sunshine (over Southern Hemisphere latitudes) so the T# counter
almost always shows you how many minutes PCsat is into its charge cycle..

There is nothing we in the Northern Hemisphere can do other than turn our
transmitters OFF so as not to add to the power load.  Things to watch:

1) If we got it into low power mode, you will see 00111111 telemetry
2) Volts need to be above 16.4v? going into eclipse (T# greater than 60)
3) To see volts, look at the first two fields after the T# in any packet
   ending with xx11,1.  There, 164 means about 16.4 volts...
4) At night you will hear PCsat packets weak and dying as it dies in each
   eclipse.

No need to flood  us with reports since the command stations are keeping
us pretty well informed.

Example telemetry provided by I6JKW
> ----------------------------------------------------
> fm PCSAT-11 to BEACON via SGATE ctl UI pid F0 len=042
> T#005,075,037,047,147,213,11111111,0000,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#015,081,065,046,094,213,11111111,0010,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#016,159,159,059,209,212,11111111,0011,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#017,028,039,149,029,213,11111111,0000,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#019,088,067,047,095,213,11111111,0010,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#020,157,157,060,208,213,11111111,0011,1
> fm PCSAT-11 to BEACON via SGATE ctl UI pid F0 len=042
> T#007,088,074,089,101,213,11111111,0010,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#021,015,036,075,120,212,11111111,0000,1
> fm W3ADO-1 to BEACON via SGATE ctl UI pid F0 len=042
> T#022,089,071,075,086,212,11111111,0001,1

de WB4APR@amsat.org, Bob

PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite  http://www.toad.net/~wclement/bruninga/mic-lite.html

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