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GET /hyperkitty/api/list/[email protected]/email/42QVLD5H6723YK7UHL2YCWO654S6MIWW/
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/42QVLD5H6723YK7UHL2YCWO654S6MIWW/", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/", "message_id": "[email protected]", "message_id_hash": "42QVLD5H6723YK7UHL2YCWO654S6MIWW", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/42QVLD5H6723YK7UHL2YCWO654S6MIWW/", "sender": { "address": "clive (a) g3cwv.co.uk", "mailman_id": null, "emails": null }, "sender_name": "Clive Wallis", "subject": "[amsat-bb] OSCAR-11 Report", "date": "2010-03-31T15:56:13Z", "parent": null, "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": " OSCAR-11 REPORT 30 March 2010\n\n\nOSCAR-11 achieved 26 years in orbit on 01 March! It was designed,\nbuilt and launched within a period of six months, using commercially\navailable 'off the shelf' components (COTS). Once again,\ncongratulations to Professor Sir Martin Sweeting G3YJO, his team at\nthe University of Surrey and groups of radio amateurs who also\ncontributed to the project. Unfortunately, the satellite wasn't\ntransmitting on its birthday, but was heard briefly, three days\nlater.\n\nThis report covers the period from 23 February to 30 March 2010.\nDuring this time the satellite was heard during three passes on 04\nMarch. Good signals were received, and decoded. There was also an\nunconfirmed report that it was heard on 25 March.\n\nDue to eclipses, deterioration of the battery and other parts of the\nsatellite, it's not possible to predict when the satellite will be\nheard in the coming months. It is likely that it may be heard\noccassionally, by stations tuning around the beacon frequency.\n\nThe on-board clock was 263 days slow, when last heard on 04 March.\nThe increasing error suggests that the clock may be stopping, when\nthe satellite is in eclipse. Sometimes, the date counter also fails\nto increment. However, the retention of the date and time does\nsuggest that a small amount of power may be still available during\neclipses.\n\nThe Beacon frequencies are -\n\nVHF 145.826 MHz. AFSK FM ASCII Telemetry\n\nUHF 435.025 MHz. OFF\n\nS-band 2401.5 MHz. OFF\n\n -------------\n\n RECEPTION REPORTS REQUESTED!\n\nPlease send reception reports to [email protected] (replace xxxxx by\ng3cwv) or post to amsat-bb. If you have a file, please do not send\nit but let me know that it is available.\n\nYou may also like to add your reception report to the live satellite\nstatus page, on the website set up by David KD5QGR and Bob WB4APR.\nThe URL is http://oscar.dcarr.org/index.php\n\nThe satellite transmits on 145.826 MHz., set receiver to NBFM.\nOSCAR-11 has a characteristic sound, rather like raspy slow morse\ncode, sending \"di di dah dah dah dah dah dah dah\" sent over a period\nof five seconds. If you are receiving a very weak signal, switch the\nreceiver to CW or SSB. You should hear several sidebands around the\ncarrier frequency and should be able to hear the characteristic\n'morse code like' sound on at least one sideband.\n\nPlease note that you need a clean noise-free signal to decode the\nsignals, and your receiver must be set to NBFM mode, for a decoder to\nwork.\n\nIf you need to know what OSCAR-11 sounds like, there is an audio\nclip on my website www.g3cwv.co.uk/ which may be useful for\nidentification and as a test signal for decoding.\n\n -------------\n\nThe satellite is now subject to eclipses during every orbit. Long\nterm predictions indicate that eclipses will occur until 2019, when\nthere will be some eclipse free periods until 2023. However these\nvery long term predictions should be regarded with caution, as large\ntracking errors can accumulate over long periods of time.\n\nWhen eclipses started around 2005 the watchdog timer often switched\nthe transmitter off before the ten day on period had finished, during\nparts of the eclipse cycle. When eclipses became a permanent feature\nof all orbits, after April 2008, the transmitter switched off within\na single orbit, thus the satellite was effectively non operational.\n\nThe satellite unexpectedly started regular transmissions in November\n2009. Although there was a small variation in the length of eclipses,\nthis wasn't enough to explain why the satellite started regular\ntransmissions. It is possible that a fault developed, which prevented\nthe watchdog timer resetting when the power supply fails, and now the\nwatchdog timer settings are no longer retained during eclipses. The\ntransmitter switches off during eclipses, and the real time clock\nstops during most of the eclipse.\n\nWhen analogue telemetry was last received, in 2005, it showed that\none of the solar arrays had failed, and there was a large unexplained\ncurrent drain on the main 14 volt bus. After 26 years in orbit the\nbattery has undergone over 100,000 partial charge/discharge cycles,\nand observations indicate that it cannot power the satellite during\neclipses.\n\nThe current status of the satellite, is that all the analogue\ntelemetry channels, 0 to 59 are zero, ie they have failed. The status\nchannels 60 to 67 are still working. The real time clock is showing a\nlarge accumulated error, although during ten minute passes the clock\nincrements correctly to within one second. The day of the month has a\nbit stuck at 'one' so the day of the month may show an error of +40\ndays for some dates. The time display has switched into 12 hour mode.\nUnfortunately, there is no AM/PM indicator, since the time display\nformat was designed for 24 hour mode.\n\nThe spacecraft computer and active attitude control system have\nswitched OFF, ie. the satellite' attitude is controlled only by the\npassive gravity boom gradient, and the satellite is free to spin at\nany speed.\n\nThe watchdog timer operates on a 20 day cycle. The ON/OFF times have\ntended to be very consistent. The average of many observations show\nthis to be 20.7 days, ie. 10.3 day s ON followed by 10.4 days OFF.\n\nListeners to OSCAR-11 may be interested in visiting my website. If\nyou need to know what OSCAR-11 should sound like, there is a short\naudio clip for you to hear. The last telemetry received from the\nsatellite is available for download. The website contains an archive\nof news & telemetry data which is updated from time to time. It also\ncontains details about using a soundcard or hardware demodulators for\ndata capture. There is software for capturing data, and decoding\nASCII telemetry. The URL is www.g3cwv.co.uk .\n\nIf you place this bulletin on a terrestrial packet network, please\nuse the bulletin identifier $BID:U2RPT148.CWV, to prevent\nduplication.\n\n73 Clive G3CWV [email protected] (please replace xxxxx by g3cwv)\n\n\n\n\n\n\u001a\n", "attachments": [] }