[amsat-bb] Re: compass-1

Mike Rupprecht mail at mike-rupprecht.de
Thu Aug 21 23:57:27 PDT 2008

Hi Jeff,

thank you for listening to COMPASS. Could you decode the beacon or did you
record it?

COMPASS is in emergency mode and the beacon is transmitting every 8..9
minutes if the voltage is higher than 2.8 volts. The RX/TX seems to work
with voltages down to 2.4 volt. This explains why COMPASS responds to
commands but no beacon sends.

If the batteries are charged and the voltage is higher than 3.7 volts (!) -
COMPASS will switch autonomous into NORMAL mode. Only in this mode the FM
transmitter (437.405MHz) is on and the satellite can send packets on

To take a picture the following points must fulfilled:
- NORMAL mode
- ADCS active and in control mode - that means COMPASS is not tumbling and
  camera is pointing to earth
- COMPASS must command to take a picture
- everyone :-) should listen to COMPASS and collect the received packets (
300 Kbyte data )
- request the missing packet frames
- compose the frames to an picture

But we are far away from this point. The first goal is - bring back COMPASS
into normal operation mode.

Thanks and 73,

-----Ursprüngliche Nachricht-----
Von: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] Im
Auftrag von Mr Jeffrey L Ross
Gesendet: Freitag, 22. August 2008 05:02
An: amsat
Betreff: [amsat-bb] compass-1

hi folks, thought i would try for compass-1. Had a good 81 degree pass my 
location just now and listened and got the last of a cw beacon as I think it

goes/xmits every 8 mins. So to get a beacon is just a matter of luck if it 
beacons while over head.
sounded powerfull though, will be looking for it the next pass's.


p.s. had to change freq from 437.275 to 437.405 for the packet. wish they 
were on the same freq.
guess I have to decide what one i want to try for.
anyone know how they xmit us the pics? or if any pics have been downloaded 
as of  yet?

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