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 solar attitude.
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@amsat.org (please replace xxxxx by g3cwv)
Hi,
UO-11 is still going strong, the following frames were captured at 04/22 23:10z: (QTH: PL04vq)
UOSAT-2 0703153060307
000000010001020002030003040004050005060006070007080008090009 100001110000120003130002140005150004160007170006180009190008 20000221000322000023000124000625000726000427000528000A29000B 30000331000232000133000034000735000636000537000438000B39000A 40000441000542000643000744000045000146000247000348000C49000D 50000551000452000753000654000155000056000357000258000D59000C 60800E615FC1620105633341644402651E0C6627EB67000168000E69000F UOSAT-2 0703153060312
000000010001020002030003040004050005060006070007080008090009 100001110000120003130002140005150004160007170006180009190008 20000221000322000023000124000625000726000427000528000A29000B 30000331000232000133000034000735000636000537000438000B39000A 40000441000542000643000744000045000146000247000348000C49000D 50000551000452000753000654000155000056000357000258000D59000C 60800E615FC1620105633341644402651E0C6627EB67000168000E69000F
73 Edward / BX1AD -----
Clive Wallis said:
OSCAR-11 REPORT 18 April 2007RECEPTION 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 solar attitude.
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@amsat.org (please replace xxxxx by g3cwv) _______________________________________________ Sent via AMSAT-BB@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
participants (2)
-
Clive Wallis -
Edward Chuang