OSCAR-11 Report

Users of OSCAR-11 may be interested in recent additions to my website. Firstly UCAP, this is a simple OSCAR-11 capture program for Windows, and may be used instead of CTERM.
It features an accurate time stamp facility, which is useful for checking the satellite's real time clock.

Secondly, the news and telemetry archives have been updated to include all the 2005 data. The URL is http://www.users.zetnet.co.uk/clivew/

During the period 14 December 2005 to 23 January 2006 the VHF beacon on 145.826 MHz. has been heard from 23 to 31 December and from 11 to 21 January.

Signals during the December passes were very variable. Sometimes received at good strength, at other times they were inaudible, even with the BFO switched ON (ie. in CW mode). Signals during the January passes tended to be much stronger, and good copy was obtained on most passes.

The on-board clock continues to accumulate a very large error. On 21 January it was 22.14 days slow, having lost 0.33 days (8 hours) since 09 December. However, the rate of change of clock error appears to vary between zero and half an hour per day, over short periods. The greatest changes seem to correspond with poor signals, which suggests 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 satellite is now in continuous sunlight until around 06 May, when eclipses will start again. This should help the satellite to continue transmitting, although continuous sunlight can cause problems due to excessive temperatures. Power supply problems can be caused by poor pointing attitude, ie the sunlight illuminating the ends of the satellite, instead of the solar arrays.

The watchdog timer now appears to have resumed operation on the 20 day cycle, ie. approximately ten days ON followed by 10 days OFF. However, at any time, poor solar attitude, and battery 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 -
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 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
Email: g3cwv@<no spam>amsat.org

Online Satellite Pass Predictions:
http://www.amsat.org/amsat-new/tools/predict/

AMSAT-UK produce a quarterly newsletter "Oscar News" which is full of Amateur Satellite information. For membership details contact the secretary Jim Heck G3WGM
Tel: +44 (0)1258 453959
E-mail: g3wgm@amsat.org
Website: http://www.uk.amsat.org/

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