April 2008 - AMSAT-BB - mailman.amsat.org

Satellite Frequency Control
by RFI-EMI-GUY 30 Apr '08

30 Apr '08

Sounds like a good idea! I was at SVHFS last week and there was a lot of discussion and design effort toward GPS derived frequency control for EME and microwave roamers. -- Joe Leikhim K4SAT "The RFI-EMI-GUY"© "Treason doth never prosper: what's the reason? For if it prosper, none dare call it treason." "Follow The Money" ;-P

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Delfi-C3 Not Heard In Northern CA
by Bill Ress 30 Apr '08

30 Apr '08

Delfi-C3 wasn't heard from during today's 1725Z and 1858Z passes over Northern CA. Anyone have different results?? Regards...Bill - N6GHz

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Delfi-C3 status update 30 April 2008 08:00 UTC
by Wouter Jan Ubbels 30 Apr '08

30 Apr '08

Hi all, Delfi-C3 is in orbit and healthy, despite some minor issues, please find a status update below: 1. Telemetry indicates that all solar panels and antennas have deployed properly 2. Telemetry indicates nominal values for all housekeeping values 3. We have already obtained payload data, and have been able to generate IV curves of the Thin Film Solar Cell experiment, note that those uring RASCAL can view the IV curves by clicking Options-->show IV curves in RASCAL. 4. The spacecraft is operating in science mode, we have had one orbit in emergency mode, which was most probably due to a databus issue 5. Up till now we have received 7000+ (!) frames from amateurs using RASCAL around the globe, amazing, thank you all so much!! 6. We have verified command uplink functionality yesterday, and were able to command the spacecraft today on the low elevation (4.9max) pass over our GS at 0737UTC 7. The spacecraft has decided to consistently use the backup radio on 145.930MHz for its telemetry downlink, we were able to request a full on-board database dump while in range of our groundstation yesterday and analysis of the database confirms this. We currently have a good understanding why this is the case. We will try to switch downlinks to the primary radio on 145.870MHz during the next good pass over our GS, so amateurs in Western Europe might want to check that frequency also and might experience intermittent telemetry while we are commanding. Note that we suspect that the TX frequency could be 1 to 2 kHz lower on this radio, so tuning around slowly is the best strategy. 8. The spacecraft seems to have an issue with the downlink TX switching off into the orbit, which is the reason while Delfi-C3 has not been heard on most descending passes over VK/ZL, we think we have a good understanding of why it is. The TX itself is fine, but it switches off automatically when it does not get data from the OBC for a certain amount of time. We are working on resolving this issue. This also happened during the pass over our GS at 0737 UTC but we were able to command it back on. For those in Western Europe we would like to ask to keep tracking Delfi-C3 even if you can not hear it at first, as we will try to turn the TX back on as soon as we notice that it has been turned off. 9. Thank you all for your observations on the spin rate, these are really helpful! We currently think that the spacecraft is tumbling with approx 10deg/second, which corresponds to a 36 second period. Since the s/c downlink antenna is almost truely circular, polarization sense can change from RHCP to LHCP completely depending on s/c orientation, we use circular antennas on our GS as well, and when we switch to the opposite polarizaiton sense the signal is wiped out completely, switching back gives solid copy with strong sigs. 10. NORAD object E #32787 seems to match best thanks for all your observations and efforts so far! 73 on behalf of the Delfi-C3 team, Wouter Jan Ubbels

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Re: Delfi-C3 status update -THANK YOU!!!
by Stefan Wagener 30 Apr '08

30 Apr '08

Thanks! What a great example of keeping the community informed. By providing us with a very interesting satellite, a nice software tool, access to data and the opportunity to share in your experiences your team has done a tremendous job for the satellite amateur radio community and the promotion of our hobby and interests. Thank you and please keep it up. I am looking forward to tonight catching more telemetry. :-) 73, Stefan VE4NSA > Date: Wed, 30 Apr 2008 10:16:58 +0200> From: wjubbels(a)gmail.com> To: amsat-bb(a)amsat.org> CC: rascal(a)delfic3.nl> Subject: [amsat-bb] Delfi-C3 status update 30 April 2008 08:00 UTC> > Hi all,> > Delfi-C3 is in orbit and healthy, despite some minor issues, please find a> status update below:> > 1. Telemetry indicates that all solar panels and antennas have deployed> properly> > 2. Telemetry indicates nominal values for all housekeeping values> > 3. We have already obtained payload data, and have been able to generate IV> curves of the Thin Film Solar Cell experiment, note that those uring> RASCAL can view the IV curves by clicking Options-->show IV curves in> RASCAL.> > 4. The spacecraft is operating in science mode, we have had one orbit in> emergency mode, which was most probably due to a databus issue> > 5. Up till now we have received 7000+ (!) frames from amateurs using RASCAL> around the globe, amazing, thank you all so much!!> > 6. We have verified command uplink functionality yesterday, and were able to> command the spacecraft today on the low elevation (4.9max) pass over our GS> at 0737UTC> > 7. The spacecraft has decided to consistently use the backup radio on> 145.930MHz for its telemetry downlink, we were able to request a full> on-board database dump while in range of our groundstation yesterday and> analysis of the database confirms this. We currently have a good> understanding why this is the case. We will try to switch downlinks to the> primary radio on 145.870MHz during the next good pass over our GS, so> amateurs in Western Europe might want to check that frequency also and might> experience intermittent telemetry while we are commanding. Note that we> suspect that the TX frequency could be 1 to 2 kHz lower on this radio, so> tuning around slowly is the best strategy.> > 8. The spacecraft seems to have an issue with the downlink TX switching off> into the orbit, which is the reason while Delfi-C3 has not been heard on> most descending passes over VK/ZL, we think we have a good understanding of> why it is. The TX itself is fine, but it switches off automatically when it> does not get data from the OBC for a certain amount of time. We are working> on resolving this issue. This also happened during the pass over our GS at> 0737 UTC but we were able to command it back on. For those in Western Europe> we would like to ask to keep tracking Delfi-C3 even if you can not hear it> at first, as we will try to turn the TX back on as soon as we notice that it> has been turned off.> > 9. Thank you all for your observations on the spin rate, these are really> helpful! We currently think that the spacecraft is tumbling with approx> 10deg/second, which corresponds to a 36 second period. Since the s/c> downlink antenna is almost truely circular, polarization sense can change> from RHCP to LHCP completely depending on s/c orientation, we use circular> antennas on our GS as well, and when we switch to the opposite polarizaiton> sense the signal is wiped out completely, switching back gives solid copy> with strong sigs.> > 10. NORAD object E #32787 seems to match best> > > thanks for all your observations and efforts so far!> > 73 on behalf of the Delfi-C3 team,> > Wouter Jan Ubbels> _______________________________________________> Sent via AMSAT-BB(a)amsat.org. Opinions expressed are those of the author.> Not an AMSAT-NA member? Join now to support the amateur satellite program!> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

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Delphi Elements Download Help
by Ronald Long 30 Apr '08

30 Apr '08

PE4WJ wrote: >Furthermore, Delfi-C3 is now listed on celestrack with identifier DELFI-C3 , >as object #32787, these TLE's are also on our mission ops page. I am using Nova download from celestrak but do not find Delphi-C3. In the download setup I have selected NORAD/elements and stations, amateur, visual, science, engineering and other categories. What am I doing wrong? ron w8gus

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Delfi-C3 RASCAL tuning & TLE's
by Wouter Jan Ubbels 30 Apr '08

30 Apr '08

Hi all, we have added a section to our RASCAL tuning guide in order to make achieving sync in RASCAL easier, see http://www.delfic3.nl/index.php?option=com_content&task=view&id=94&Itemid=1… I have also included it in this mail for clarity: Tuning can sometimes be difficult, in the presence of Doppler shift, fading due to polarization changes, frequency offset due to temperature of the spacecraft oscillators and there is the possibility that the Costas Loop indicates a false sync because of lock on one of the signal's sidebands. If possible, you can use a waterfall display in software like MixW running parallel to RASCAL which will give you an indication of the centerfrequency. During transmission of AX.25 flags, the actual carrier frequency is the highest peak in the spectrum, with a couple of sidebands exactly 150Hz apart, looks like a comb. Now, using the waterfall display, tune such that this highest peak corresponds to 1600Hz +/-100Hz, in order to achieve sync. Furthermore, Delfi-C3 is now listed on celestrack with identifier DELFI-C3 , as object #32787, these TLE's are also on our mission ops page. Today we also verified that our backup command receiver functions well, we are still working on the TX drop out issue. 73 on behalf of the Delfi-C3 team, Wouter Jan Ubbels PE4WJ

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Satellite Frequency Control
by David Barber 30 Apr '08

30 Apr '08

Perhaps this is a really stupid question? The deviation from the intended frequency of operation of a satellite is often mentioned here therefore would it not be possible to lock the frequency of the payload to a GPS derived source? I appreciate this may not be practical on Cubesats but for longer life products? Comments...

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DELFI C 3
by Luc Leblanc 30 Apr '08

30 Apr '08

Nothing heard on the 1405Z south bound pass on 145.930 Mhz "-" Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE

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Cute-1.7+APDII over West Malaysia
by Sion Chow Q. C. (9W2QC) 30 Apr '08

30 Apr '08

Dear All, Here is an MP3 recording of Cute-1.7+APDII over West Malaysia. Satellite was tracked using Object - J and maximum elevation was 10 degree. Time was 2132 Local or 1332 UTC. http://www.9w2qc.net/amsatbb/cute30apr0932.mp3 The MP3 recording is unedited as I am copying this remotely via VNC/Teamspeak. I think I heard another satellite transmitting towards the end of the pass on top of Cute-1.7 + APDII. 73, Sion Chow Q. C., 9W2QC.

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Re: Delfi-C3 status update 30 April 2008 08:00 UTC
by Robert Turlington 30 Apr '08

30 Apr '08

Hi All a good pass of delfi at 1150 utc got 50 packets decoded the beacon was switching on and off every 60secs or so starting at 1155-30 secs approx finally switched off at1200-20secs or there aboutsRegards Robert G8ATE > Date: Wed, 30 Apr 2008 10:16:58 +0200> From: wjubbels(a)gmail.com> To: amsat-bb(a)amsat.org> CC: rascal(a)delfic3.nl> Subject: [amsat-bb] Delfi-C3 status update 30 April 2008 08:00 UTC> > Hi all,> > Delfi-C3 is in orbit and healthy, despite some minor issues, please find a> status update below:> > 1. Telemetry indicates that all solar panels and antennas have deployed> properly> > 2. Telemetry indicates nominal values for all housekeeping values> > 3. We have already obtained payload data, and have been able to generate IV> curves of the Thin Film Solar Cell experiment, note that those uring> RASCAL can view the IV curves by clicking Options-->show IV curves in> RASCAL.> > 4. The spacecraft is operating in science mode, we have had one orbit in> emergency mode, which was most probably due to a databus issue> > 5. Up till now we have received 7000+ (!) frames from amateurs using RASCAL> around the globe, amazing, thank you all so much!!> > 6. We have verified command uplink functionality yesterday, and were able to> command the spacecraft today on the low elevation (4.9max) pass over our GS> at 0737UTC> > 7. The spacecraft has decided to consistently use the backup radio on> 145.930MHz for its telemetry downlink, we were able to request a full> on-board database dump while in range of our groundstation yesterday and> analysis of the database confirms this. We currently have a good> understanding why this is the case. We will try to switch downlinks to the> primary radio on 145.870MHz during the next good pass over our GS, so> amateurs in Western Europe might want to check that frequency also and might> experience intermittent telemetry while we are commanding. Note that we> suspect that the TX frequency could be 1 to 2 kHz lower on this radio, so> tuning around slowly is the best strategy.> > 8. The spacecraft seems to have an issue with the downlink TX switching off> into the orbit, which is the reason while Delfi-C3 has not been heard on> most descending passes over VK/ZL, we think we have a good understanding of> why it is. The TX itself is fine, but it switches off automatically when it> does not get data from the OBC for a certain amount of time. We are working> on resolving this issue. This also happened during the pass over our GS at> 0737 UTC but we were able to command it back on. For those in Western Europe> we would like to ask to keep tracking Delfi-C3 even if you can not hear it> at first, as we will try to turn the TX back on as soon as we notice that it> has been turned off.> > 9. Thank you all for your observations on the spin rate, these are really> helpful! We currently think that the spacecraft is tumbling with approx> 10deg/second, which corresponds to a 36 second period. Since the s/c> downlink antenna is almost truely circular, polarization sense can change> from RHCP to LHCP completely depending on s/c orientation, we use circular> antennas on our GS as well, and when we switch to the opposite polarizaiton> sense the signal is wiped out completely, switching back gives solid copy> with strong sigs.> > 10. NORAD object E #32787 seems to match best> > > thanks for all your observations and efforts so far!> > 73 on behalf of the Delfi-C3 team,> > Wouter Jan Ubbels> _______________________________________________> Sent via AMSAT-BB(a)amsat.org. Opinions expressed are those of the author.> Not an AMSAT-NA member? Join now to support the amateur satellite program!> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _________________________________________________________________ Search and win with BigSnapSearch.com http://www.bigsnapsearch.com

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