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www.southgatearc.org
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OSCAR-11 REPORT 07 May 2006Reception Reports Requested! Due to solar eclipses (see below) the beacon may only transmit for a short time, perhaps only a few orbits. Any reception reports would be appreciated. Please e-mail g3cwv@<no spam>amsat.org, or post to AMSAT-BB. If you are unfamiliar with the sound of OSCAR-11, there is an audio clip on my website http://www.users.zetnet.co.uk/clivew/ During the period 16 April to 06 May 2006 the VHF beacon on 145.826 MHz. has been heard from 25 April to 05 May. Signal strengths have been very variable during this ten day period, sometimes too weak to detect, even with the receiver set to CW mode, at other times signals were of good decoding quality. Frequent changes in polarisation were also observed on some passes. OSCAR-11's VHF beacon switched OFF on 05 May, as expected. This was just one day before the solar eclipses were due to start. These eclipses will continue until 04 August 2006, reaching a maximum duration of 22% around 19 June. If the satellite behaves in the same way as it did last year, the beacon may only be heard for very short times, during the eclipse season. The on-board clock continues to show a very large accumulated error. On 05 May it was 22.76456 days slow. The clock lost two hours during the last OFF period, and nine hours during the last transmission period. The observations of clock errors suggest that the clock may slow or stop when the battery voltage is low. All the analogue telemetry channels, 0 to 59 are zero, ie they have failed. The status channels 60 to 67 are still working. The watchdog timer now appears to have resumed operation on the 20 day cycle. During the last three months the ON/OFF times have been very consistent, and many observations show this to be 20.7 days, ie. 10.3 days ON followed by 10.4 days OFF. However, during the present solar eclipse season, power supply problems, may result in a low 14 volt line supply, which may cause the beacon to switch OFF prematurely, and reset the watchdog timer cycle. The Beacon frequencies are - Listeners to OSCAR-11 may be interested in visiting my website which 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 http://www.users.zetnet.co.uk/clivew/ 73 Clive G3CWV
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