Delfi-C3 Update

Wouter Jan Ubbels PE4WJ provides the latest update on the Delfi-C3 / DO-64 Amateur radio 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 transponder mode during the 10:00 UTC pass today (July 29th) over the Delfi-C3 ground station in The Netherlands. This means that the spacecraft now boots in transponder mode 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 ground station 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

Delfi-C3: http://www.delfic3.nl/

Delfi-C3 Mission Status:
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