[amsat-bb] OSCAR-11 Report

Clive Wallis clive at g3cwv.co.uk
Mon Mar 10 03:45:10 PDT 2014

                OSCAR-11 30th BIRTHDAY REPORT

OSCAR-11 (AKA UoSAT-2 and UO-11) celebrated it's 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,

The 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).

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. 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 URL is

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 www.g3cwv.co.uk/oscar11.htm
. 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 at amsat.org (please replace the x's by g3cwv)

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