[amsat-bb] Delfi-C3 Status update 29 July 12:30 UTC

Wouter Jan Ubbels wjubbels at gmail.com
Tue Jul 29 05:49:55 PDT 2008

Hi all,

please find below the latest status update of the Delfi-C3 / DO-64 satellite

1. We have concluded the first three months of science mission with
great success. A big word of thanks to all amateur radio operators
around the world for collecting and forwarding telemetry, sending
reception reports and observations, and thanks for all the tremendous
support we have received. As of today, we have collected 396564 AX.25
frames through the worldwide network... a truly amazing number. Thank
you all so much.

2. Delfi-C3 has been switched to permanent transpondermode during the
10:00 UTC pass today (July 29th) over the Delfi-C3 groundstation in
The Netherlands. This means that the spacecraft now boots in
transpondermode as soon as the spacecraft exits eclipse. This was
verified by a successful OBC database dump shortly after that.

3. We plan to switch the satellite back into either basic or science
mode, approx. once every 2 weeks for short times during passes over
our groundstation for housekeeping purposes. During these passes
either the 145.870MHz or 145.930MHz downlink will be on transmitting
1200Bd BPSK, and the transponder will then be off. We would like to
encourage everyone to forward telemetry using RASCAL in the usual way
during these passes. Longer periods of BPSK telemetry will be
announced on the BB.

4. Reports have indicated a slight frequency offset of the
transponder, i.e. an uplink of 435.556MHz corresponds to 145.900MHz in
the downlink passband. This was actually known before launch, and is
caused by a slight frequency offset in one of the spacecraft's local
oscillators. The video on YouTube is a video from the first
transponder contact using our "flatsat" transponder prototype in early
2007, which is not the same as the flight model. However, the flatsat
prototype also showed a slight frequency offset, as G0MRF pointed out.

5. The transponder mode beacon is at 145.870MHz, approx 10dB below
PEP, transmitting a CW beacon message, followed by a commemorative
Sputnik message consisting of 6 dits. Actually, the CW beacon is
transmitted using Double Sideband, there are two CW carriers 1200Hz
apart. (Guess where that number comes from hi:)

6. Reports on the transponder's operation are more than welcome,
either on the BB (which is read by us on a daily basis) or directly to
info at delfic3.nl

Having said all this, the team is happy to open the transponder for
use, and wishes you good DX. Enjoy!

73 on behalf of the Delfi-C3 team,

Wouter Jan Ubbels PE4WJ

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