[amsat-bb] Re: OSCAR-11 Report
zack.kd8ksn at hotmail.com
Sat Oct 2 15:50:59 PDT 2010
Thank you for sending this out - this may answer something I was wondering
about a few weeks ago....
I was out during a morning 1300-1400z HO68 pass about 3-4 weeks ago, and as
I was doing the pass, I noticed the S-meter on my TRANSMIT HT was peaking at
about S7 (I was using one HT to receive the 435.675 downlink, and the other
for the 145.825 uplink). I turned the volume up on the transmit HT to see
what it was, and I heard the EXACT same audio that you have on your webpage
of Oscar-11's telemetry beacon on 145.826 (1 kHz off of the uplink for
HO68). I am assuming that what I heard on my transmit HT was probably the
Oscar-11 beacon - could anyone confirm that?
From: "Clive Wallis" <clive at g3cwv.co.uk>
Sent: Saturday, October 02, 2010 11:54 AM
To: "amsat" <amsat-bb at amsat.org>
Subject: [amsat-bb] OSCAR-11 Report
> OSCAR-11 REPORT 30 September 2010
> This report covers the period from 30 March to 30 September
> 2010. During this time the satellite was silent until it was
> heard by JA0CAW on 29 August. Since then, it was heard until
> 08 September and from 18 to 29 September. Excellent signals
> have been reported from stations located around the world,
> and good copy obtained from decoded telemetry frames.
> There has been a significant change since the previous
> period of activity which ended in March 2010. The on-board
> clock is now very stable. It's gained only three seconds in
> 30 days. This is comparable with its accuracy when the
> satellite was fully operational. During its first 21 years
> it gained approximately one minute per year. However, there
> is still an accumulated loss of 309 days, which has occurred
> during eclipses of the last few years.!
> The other change is that it's now transmitting during
> eclipses, although signals are weaker at those times. This
> indicates that there is still some capacity remaining in the
> These two changes suggest that some part of the system may
> have recently failed 'open circuit' thus reducing the
> overall power drain of the system, and allowing more power
> to be available during eclipses. There was an unexplained
> current drain observed when analogue telemetry was last
> transmitted. This fault might have cleared. Interestingly,
> the status telemetry shows that the Digital Store & Readout
> experiment has switched off, since the satellite was
> previously heard in February.
> The satellite appears to be operating for ten days on,
> followed by ten days off, so it should start transmitting
> again around 09 October.
> The Beacon frequencies are -
> VHF 145.826 MHz. AFSK FM ASCII Telemetry
> UHF 435.025 MHz. OFF
> S-band 2401.5 MHz. OFF
> Reception reports have been received from Bernard FY1LE,
> Roland DG1EBR, Mike DK3WN, Tetsu JA0CAW, Adam SQ8MFC,
> MM0DNX, Tony VK3KKP/G8HIM, Martin DC1MAR, John M0BIC,
> Etienne F1GRR and Carlos KD6GRF. Many thanks to everyone.
> Many reports have also been added to the live satellite
> status page, on the website set up by David KD5QGR and Bob
> WB4APR. This is a very convenient and easy to use facility,
> which shows the current status of all the amateur
> satellites. Strongly recommended for future reports! The
> URL is http://oscar.dcarr.org/index.php
> For the benefit of new listeners, here is a short history
> of OSCAR-11. It was lauched in 1984, providing telemetry
> and other digital services for amateur radio and educational
> users. During its many years of operation it survived long
> periods of eclipses and continuous full sunlight.
> In 2002 the satellite reverted to its default mode of
> operation, controlled by the watchdog timer. In 2005 all the
> analogue telemetry channels failed. Solar eclipses also
> started to cause the watchdog timer cycle to reset, which
> switched off the satellite for approximately 15 days.
> In 2008 solar eclipses became a permanent feature of every
> orbit, causing the satellite to switch off for about 15
> days, probably after only one orbit of transmission. Thus
> the satellite was not expected to be heard again for any
> continuous period until 2019, when there will be some
> eclipse free periods. However, the satellite started
> transmissions unexpectedly in November 2008. These continued
> until March, when it was followed by silence until until the
> recent period of activity.
> OSCAR-11 transmits on 145.826 MHz., set receiver to NBFM.
> The satellite has a characteristic sound, rather like raspy
> slow morse code, sending "di di dah dah dah dah dah dah dah"
> sent over a period of five seconds. If you are receiving a
> very weak signal, switch the receiver to CW or SSB. You
> should hear several sidebands around the carrier frequency
> and should be able to hear the characteristic 'morse code
> like' sound on at least one sideband.
> Please note that you need a clean noise-free signal to
> decode the signals, and your receiver must be set to NBFM
> mode, for a decoder to work.
> If you need to know what OSCAR-11 sounds like, there is an
> audio clip on my website www.g3cwv.co.uk/ which may be
> useful for identification and as a test signal for decoding.
> The current status of the satellite, is that all the
> analogue telemetry channels, 0 to 59 are zero, ie they have
> failed. The status channels 60 to 67 are still working. The
> real time clock is showing a large accumulated error, but is
> now incrementing accurately to within a few seconds per
> month. The day of the month has a bit stuck at 'one' so the
> day of the month may show an error of +40 days for some
> dates. The time display has switched into 12 hour mode.
> Unfortunately, there is no AM/PM indicator, since the time
> display format was designed for 24 hour mode.
> The spacecraft computer and active attitude control system
> have switched OFF, ie. the satellite' attitude is controlled
> only by the passive gravity boom gradient, and the satellite
> is free to spin at any speed.
> The watchdog timer now operates on a 20 day cycle. The
> ON/OFF times have tended to be very consistent. The average
> of many observations have shown this to be 20.7 days, ie.
> 10.3 day s ON followed by 10.4 days OFF.
> Listeners to OSCAR-11 may be interested in visiting my
> website. If you need to know what OSCAR-11 should sound
> like, there is a short audio clip for you to hear. The last
> telemetry received from the satellite is available for
> download. The website contains an archive of news &
> telemetry data which is updated from time to time. 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.g3cwv.co.uk .
> If you place this bulletin on a terrestrial packet network,
> please use the bulletin identifier $BID:U2RPT149.CWV, to
> prevent duplication.
> 73 Clive G3CWV xxxxx at amsat.org (please replace xxxxx by g3cwv)
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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