OSCAR-11 30th Birthday Report



OSCAR-11 (AKA UoSAT-2 and UO-11) celebrated its 30th birthday in space on 01 March! It was designed, built and launched within a period of six months, using commercially available ‘off the shelf’ components (COTS). Once again, congratulations to Professor Sir Martin Sweeting G3YJO, his team at the University of Surrey and the groups of radio amateurs who also contributed to the project.

This report covers the period from 01 January 2013 to 05 March 2014. During this time there have been no significant changes apart from the gradual drift of the on-board clock. There was also an advance of one day in the displayed date. This was caused by a known leap year problem in the date chip, which has always existed since launch. Owing to the large accumulated time/date error 29 February 2012 on the satellite occurred in January 2013 on Earth!  The satellite has been transmitting on a regular cycle of 10.35 days on followed by 10.35 days off.

Good copy has been obtained obtained from decoded telemetry frames and many reports have been posted on the DCARR general satellite status website http://oscar.dcarr.org/

UOSAT_OSCAR-11The satellite continues to be subjected to eclipses during each orbit, resulting in weaker signals at those times. During the winter in the UK the evening passes were in the Earth’s shadow, and very weak signals have been received, which could not be demodulated and could be only detected with the receiver in CW mode . As the longer daylight hours of summer approach, the evening passes in the UK should gradually become clear of eclipses, resulting in stronger signals. Eclipses are expected to continue until 2019.

The on-board clock gained 98 seconds during the 14 month reporting period, which is comparable with the 60 seconds gain per year when the satellite was launched. There is however a large accumulated error of 307.54090 days slow. This was caused mainly by the clock stopping during eclipses, when there was also an unknown drain on the power supply. The units of the least significant digit correspond approximately to seconds (0.86 seconds actually).

UOSAT 2 / OSCAR-11 with Dave Brock UoS kneeling Christine Sweeting G6APF and Neville Bean G8NOB

UOSAT 2 / OSCAR-11 with Dave Brock UoS kneeling Christine Sweeting G6APF and Neville Bean G8NOB

At the present time, while OSCAR-11 is operating in a predictable way, please DO NOT send reports or files by e-mail. However, could all listeners continue to enter their reports on the general satellite status website http://oscar.dcarr.org/ . This is a very convenient and easy to use facility, which shows the current status of all the amateur satellites, and is of use to everyone. Reports around the expected times of switch-on and switch-off are of special interest, especially for times 13:00 to 18:00 and 22:00 to 08:00 UTC, to when the satellite is out-of-range in the UK .

The VHF beacon frequency is 145.826 MHz.  AFSK FM ASCII Telemetry. The satellite is operating in the default mode, controlled by the watchdog timer, with a cycle time of 20.7 days. 10.35 days on followed by 10.35 days off.

An extended version of this report is available on my website, and new listeners to OSCAR-11 should read this for
further information. The URL is http://www.g3cwv.co.uk/oscar11.htm

Martin Sweeting G3YJO testing the UO-11 digitalker

Martin Sweeting G3YJO testing the UOSAT-2 UO-11 digitalker

This page contains links to the report, a short audio clip to help you identify the satellite and a file of recent telemetry received. The website also contains an archive of news & telemetry data which is updated from time to time, and details about using a soundcard or hardware demodulators for data capture. There is also software for capturing data, and decoding ASCII telemetry.

The easiest way to check whether OSCAR-11 is operational is to look at the General Satellite Status website
http://oscar.dcarr.org/index.php .

If you place this bulletin on a terrestrial packet network, please use the bulletin identifier $BID:U2RPT159.CWV, to
prevent duplication.

73 Clive G3CWV xxxxx@amsat.org (please replace the x’s by g3cwv)

OSCAR-11 / UOSAT-2 Celebrates 30 Years in Orbit

OSCAR-11 page on the DK3WN satellite blog at http://www.dk3wn.info/p/?cat=47

SSTL Blog – Happy 30th Birthday to UOSAT-2

OSCAR-9 and OSCAR-11 TV News Reports

BBC Micro ASTRID UoSAT receiver and AMSAT-UK Software Library