[amsat-bb] Re: OSCAR-11 Report
bx1ad73 at gmail.com
Sun Apr 22 19:03:31 PDT 2007
UO-11 is still going strong, the following frames were captured
at 04/22 23:10z: (QTH: PL04vq)
Edward / BX1AD
Clive Wallis said:
> OSCAR-11 REPORT
> 18 April 2007
>RECEPTION REPORTS REQUESTED!
>OSCAR-11 is expected to switch ON around 22:00 UTC 21 April. This is just
>after the start of solar eclipses, which may cause the satellite to switch OFF
>for 21 days. In the past the satellite has been very sensitive to the start
>of eclipse season, although the duration of the eclipses is initially very
>short. Please send reception reports to the the address below or post to
>amsat-bb. If you are able to record the satellite as a WAV file, please do
>so, but let me know what you have, before sending it!
>If you need to hear what the satellite sounds like, please visit my website
>www.users.zetnet.co.uk/clivew/ The satellite transmits on 145.826 MHz. set
>receiver to NBFM.
>During the period 22 March to 17 April 2007, the satellite's 145.826 MHz.
>beacon was heard from 01 to 11 April . Excellent signals have beeen heard
>on most passes, and good copy of the telemetry obtained.
>The on-board clock has continued to be of interest. At the start of this ON
>period the clock was 37.21439 days slow. During this period, the date
>passed through the transition from February to March. Instead of changing
>the month after 28 February, the date incremented to 29 February, and then
>changed to 01 March. Previously, since 1992, a fault had occurred every
>leap year, when date had failed to increment to 29 February.
>When last heard the total clock error was 38.21441 days slow.
>If the satellite's watchdog timer continues to operate normally, the beacon
>should switch ON around 21/22 April 2007. However, solar eclipses are
>expected to start on 20 April and will continue until 23 August. If the
>satellite performs as it did last year, it is unlikely to be heard, for any
>length of time, during the eclipse season.
>I am indebted to David G8OQW, Jeff KB2M, Edward BX1AD, Sil ZL2CIA, Gene
>WA4UKX and Rik, ON4GJ for their reports. Many thanks.
>The current status of the satellite, is that all the analogue telemetry
>channels, 0 to 59 are zero, ie they have failed. The status channels 60 to
>67 are still working. The real time clock is showing a large accumulated
>error, although over short periods timekeeping is accurate to a few
>seconds per month. The day of the month has a bit stuck at 'one' so the
>day of the month is showing an error of +40 days. The time display has
>switched into 12 hour mode, with the date changing at around 05 hours UTC.
>The spacecraft computer and active attitude control system have switched
>OFF, ie. the satellite' attitude is controlled only by the passive gravity
>boom gradient, and the satellite is free to spin at any speed. When
>telemetry was last received it showed that one of the solar arrays had
>failed, and there was a large unexplained current drain on the main 14 volt
>bus. After 22 years in orbit the battery has undergone around 100,000
>partial charge/discharge cycles, and observations suggest that it cannot
>power the satellite during eclipses, or sometimes during periods of poor
>The watchdog timer now operates on a 20 day cycle. The ON/OFF times have
>tended to be very consistent. The average of many observations show this to
>be 20.7 days, ie. 10.3 days ON followed by 10.4 days OFF. However, poor
>solar attitude may result may result in a low 14 volt line supply, which
>may cause the beacon to switch OFF prematurely, and reset the watchdog
>timer cycle. When this occurs, the beacon is OFF for 20.7 days.
>The Beacon frequencies are -
>VHF 145.826 MHz. AFSK FM ASCII Telemetry
>UHF 435.025 MHz. OFF
>S-band 2401.5 MHz. OFF
>Listeners to OSCAR-11 may be interested in visiting my website. If you need
>to know what OSCAR-11 should sound like, there is a short audio clip for
>you to hear. The website contains an archive of news & telemetry data. It
>also contains details about using a soundcard or hardware demodulators for
>data capture. There is software for capturing data, and decoding ASCII
>telemetry. The URL is www.users.zetnet.co.uk/clivew/
>If you place this bulletin on a terrestrial packet network, please
>use the bulletin identifier $BID:U2RPT132.CWV, to prevent duplication.
>73 Clive G3CWV xxxxx at amsat.org (please replace xxxxx by g3cwv)
>Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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