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 battery.
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 [email protected] (please replace xxxxx by g3cwv)
Clive,
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?
73,
Zack KD8KSN EN80sd
-------------------------------------------------- From: "Clive Wallis" [email protected] Sent: Saturday, October 02, 2010 11:54 AM To: "amsat" [email protected] Subject: [amsat-bb] OSCAR-11 Report
OSCAR-11 REPORT 30 September 2010This 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 battery.
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 [email protected] (please replace xxxxx by g3cwv)
_______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
On Sat, 2010-10-02 at 18:50 -0400, Zachary Beougher wrote:
HO68). I am assuming that what I heard on my transmit HT was probably the Oscar-11 beacon - could anyone confirm that?
Almost certainly. I've heard it several times, including last Monday while I was out mobile. Around 11am local, it was loud even going through the Charing Cross cutting in the middle of Glasgow - obviously I couldn't hear it while I was in the tunnel section - and remained so for a good five minutes. When I was out in the clear away from buildings it was a solid fully-quieting signal.
Has anyone decoded anything off it yet?
Gordon MM0YEQ
On 02/10/2010 23:50, Zachary Beougher wrote:
Clive,
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?
If it sounds like the audio on my website, it is OSCAR-11! There is no other satellite which sounds like that!
As it's on the FM uplink for HO-68, we might be able to hear UO-11 being relayed by HO-68 onto 435.675 MHz. !
There's no problem decoding UO-11, details on my website www.g3cwv.co.uk
73 Clive G3CWV
Hitchin, North Hertfordshire, UK
participants (4)
-
Clive Wallis -
Clive Wallis -
Gordon JC Pearce -
Zachary Beougher