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Re: Delfi-C3 Status update 29 July 12:30 UTC



Hi Wouter Jan,

Congratulations !

As HAM radio amateurs we all have enjoyed to cooperate & contribute to this
scientific/commercial first part of the mission for (amongst others) the
following reasons:
- your very transparant communication on status (pre and post launch)
- a prompt Q&A handling by the command team
- telemetry decoding SW very easy to use & install (+ auto telemetry forwarding)

Please keep us posted on the conclusions of the mission and the lessons
learned... and we have also learned, as we do from each new satellite.
Observing the tumbling (rotation rate) for example was interesting, as
well as trying to figure out the on/off switching as a function of the
telemetry.

What I found to be improved in my station/set-up after this was the following:
Delfi C3 had a drift in frequency during a pass, which was predictable.
However, automatic doppler correction SW does not provide today an option
to insert functions for additional frequency drift. This blocked me in
having my station running 24/7 to monitor Delfi C3 (as I needed to correct
the frequency manually a bit during a pass), sorry for that. It is something
for me to think about how to improve.

The transponder is working well and the receiver uplink is sensitive.
Yesterday evening I made a short QSO with SP9FPP:
http://www.pa3guo.com/delfi_c3_30jul08_1955utc_sp9fpp_pa3guo.mp3
(distortion in the 1st part of the mp3 is due to my recording, the sat is great)

A big thank you for the given opportunity to the HAM radio community to
contribute to your project, and of course: THANKS FOR THE TRANSPONDER !

73s, Henk, PA3GUO
http://www.pa3guo.com


> 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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