[amsat-bb] OSCAR-11 Report

[Clive Wallis]

                    OSCAR-11 REPORT

                     16 June 2007

During the period 15 May to 15 June 2007, no signals have been received
from the satellite's 145.826 MHz. beacon. I have not received any
reception reports.

The satellite is currently subject to solar eclipses, which will continue
until 20 August.  The duration of the eclipses has now reached its maximum
time of 23 minutes and will now start to decrease.

The battery can no longer power the satellite during the eclipse season.
When the battery voltage decreases to a preset level, the watchdog timer
resets, and the beacon is turned off for approximately 21 days.  When the
satellite restarts, eclipses could cause the beacon to switch OFF, after a
short time, probably less than one orbit. This short transmission could
occur any where over the world, and could be repeated at 20.7 day
intervals.

Owing to the lack of accurate timings, it is impossible to predict when and
where the satellite will be heard during these short transmission periods.
It is just possible that someone tuning around 145.826 MHz. may hear the
satellite, by chance.

Observations during the last period of sustained operation (22 to 28 April)
showed that the satellite could survive eclipses below 12 minutes duration.
This means that sustained transmissions could start any time after 10
August, when then eclipse duration will have decreased to below 12 minutes.
However, if the satellite had switched off just before 10 August, sustained
operation could be delayed until the end of August.

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. The current
monthly bulletin contains further details of the satellite's status. 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:U2RPT134.CWV, to prevent duplication.

73 Clive G3CWV   xxxxx at amsat.org (please replace xxxxx by g3cwv)