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{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/CBWGAGSMBH4ZH6KUT5DPT3UJZOFXMXAN/", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/", "message_id": "[email protected]", "message_id_hash": "CBWGAGSMBH4ZH6KUT5DPT3UJZOFXMXAN", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/CBWGAGSMBH4ZH6KUT5DPT3UJZOFXMXAN/", "sender": { "address": "clive (a) g3cwv.co.uk", "mailman_id": null, "emails": null }, "sender_name": "Clive Wallis", "subject": "[amsat-bb] OSCAR-11 Report", "date": "2010-10-02T15:54:02Z", "parent": null, "children": [ "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/PK7P47V6VDOWKLJD6RPHF2DDVHXD2UBI/" ], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "\n OSCAR-11 REPORT 30 September 2010\n\n\nThis report covers the period from 30 March to 30 September\n2010. During this time the satellite was silent until it was\nheard by JA0CAW on 29 August. Since then, it was heard until\n08 September and from 18 to 29 September. Excellent signals\nhave been reported from stations located around the world,\nand good copy obtained from decoded telemetry frames.\n\nThere has been a significant change since the previous\nperiod of activity which ended in March 2010. The on-board\nclock is now very stable. It's gained only three seconds in\n30 days. This is comparable with its accuracy when the\nsatellite was fully operational. During its first 21 years\nit gained approximately one minute per year. However, there\nis still an accumulated loss of 309 days, which has occurred\nduring eclipses of the last few years.!\n\nThe other change is that it's now transmitting during\neclipses, although signals are weaker at those times. This\nindicates that there is still some capacity remaining in the\nbattery.\n\nThese two changes suggest that some part of the system may\nhave recently failed 'open circuit' thus reducing the\noverall power drain of the system, and allowing more power\nto be available during eclipses. There was an unexplained\ncurrent drain observed when analogue telemetry was last\ntransmitted. This fault might have cleared. Interestingly,\nthe status telemetry shows that the Digital Store & Readout\nexperiment has switched off, since the satellite was\npreviously heard in February.\n\nThe satellite appears to be operating for ten days on,\nfollowed by ten days off, so it should start transmitting\nagain around 09 October.\n\nThe Beacon frequencies are -\n\n\nVHF 145.826 MHz. AFSK FM ASCII Telemetry\n\nUHF 435.025 MHz. OFF\n\nS-band 2401.5 MHz. OFF\n\nReception reports have been received from Bernard FY1LE,\nRoland DG1EBR, Mike DK3WN, Tetsu JA0CAW, Adam SQ8MFC,\nMM0DNX, Tony VK3KKP/G8HIM, Martin DC1MAR, John M0BIC,\nEtienne F1GRR and Carlos KD6GRF. Many thanks to everyone.\n\nMany reports have also been added to the live satellite\nstatus page, on the website set up by David KD5QGR and Bob\nWB4APR. This is a very convenient and easy to use facility,\nwhich shows the current status of all the amateur\nsatellites. Strongly recommended for future reports! The\nURL is http://oscar.dcarr.org/index.php\n\nFor the benefit of new listeners, here is a short history\nof OSCAR-11. It was lauched in 1984, providing telemetry\nand other digital services for amateur radio and educational\nusers. During its many years of operation it survived long\nperiods of eclipses and continuous full sunlight.\n\nIn 2002 the satellite reverted to its default mode of\noperation, controlled by the watchdog timer. In 2005 all the\nanalogue telemetry channels failed. Solar eclipses also\nstarted to cause the watchdog timer cycle to reset, which\nswitched off the satellite for approximately 15 days.\n\nIn 2008 solar eclipses became a permanent feature of every\norbit, causing the satellite to switch off for about 15\ndays, probably after only one orbit of transmission. Thus\nthe satellite was not expected to be heard again for any\ncontinuous period until 2019, when there will be some\neclipse free periods. However, the satellite started\ntransmissions unexpectedly in November 2008. These continued\nuntil March, when it was followed by silence until until the\nrecent period of activity.\n\nOSCAR-11 transmits on 145.826 MHz., set receiver to NBFM.\nThe satellite has a characteristic sound, rather like raspy\nslow morse code, sending \"di di dah dah dah dah dah dah dah\"\nsent over a period of five seconds. If you are receiving a\nvery weak signal, switch the receiver to CW or SSB. You\nshould hear several sidebands around the carrier frequency\nand should be able to hear the characteristic 'morse code\nlike' sound on at least one sideband.\n\nPlease note that you need a clean noise-free signal to\ndecode the signals, and your receiver must be set to NBFM\nmode, for a decoder to work.\n\nIf you need to know what OSCAR-11 sounds like, there is an\naudio clip on my website www.g3cwv.co.uk/ which may be\nuseful for identification and as a test signal for decoding.\n\nThe current status of the satellite, is that all the\nanalogue telemetry channels, 0 to 59 are zero, ie they have\nfailed. The status channels 60 to 67 are still working. The\nreal time clock is showing a large accumulated error, but is\nnow incrementing accurately to within a few seconds per\nmonth. The day of the month has a bit stuck at 'one' so the\nday of the month may show an error of +40 days for some\ndates. The time display has switched into 12 hour mode.\nUnfortunately, there is no AM/PM indicator, since the time\ndisplay format was designed for 24 hour mode.\n\nThe spacecraft computer and active attitude control system\nhave switched OFF, ie. the satellite' attitude is controlled\nonly by the passive gravity boom gradient, and the satellite\nis free to spin at any speed.\n\nThe watchdog timer now operates on a 20 day cycle. The\nON/OFF times have tended to be very consistent. The average\nof many observations have shown this to be 20.7 days, ie.\n10.3 day s ON followed by 10.4 days OFF.\n\nListeners to OSCAR-11 may be interested in visiting my\nwebsite. If you need to know what OSCAR-11 should sound\nlike, there is a short audio clip for you to hear. The last\ntelemetry received from the satellite is available for\ndownload. The website contains an archive of news &\ntelemetry data which is updated from time to time. It also\ncontains details about using a soundcard or hardware\ndemodulators for data capture. There is software for\ncapturing data, and decoding ASCII telemetry. The URL is\nwww.g3cwv.co.uk .\n\nIf you place this bulletin on a terrestrial packet network,\nplease use the bulletin identifier $BID:U2RPT149.CWV, to\nprevent duplication.\n\n73 Clive G3CWV [email protected] (please replace xxxxx by g3cwv)\n\n\n\n\n\n\u001a\n", "attachments": [] }