Hi Carl,
I've seen this recently myself too.. On the occasions when it happened here over the UK, the bird "should" have been in high power mode, but after looking at telemetry it appears that it had switched into low power mode much earlier that than usual, from memory the footprint was only half in eclipse. Also noticed that before it cuts off that there is usually 10-15 or so seconds of a silent carrier. On another occasion it cut out halfway through a SSTV transmission - this I'm almost certain shouldn't have happened due to the way the firmware was written.
Perhaps a bad solar panel contributing to low voltage when approaching eclipse? I had noticed one of the panel temps was over 75c on several passes.
It certainly looks like there is some intermittent problems beginning to raise their head, lets hope it's not a steady decline in the bird's performance as gathering the SSTV pics, telemetry etc has been a very enjoyable change to the usual FM/SSB activity.
73 de Pete
Mi0VAX
On Sat, Aug 27, 2011 at 3:59 AM, Carl Rimmer cfrimmer@gmail.com wrote:
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames
where
forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
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Hi all, I found this morning in VK6 (approx. 03:45 UTC) the MET counter said 21min 45 sec, which is approx. the time ARISSat-1 would have come back into Sunlight. Strange thing is it was on High Power - got plenty of telemetry frames but was discharging at a great rate of knots.. Looking at the data it would seem there was more discharging than charging going on over it's first 21 minutes. 1 panel said 45v, the others were around 15v so the part that was facing direct sunlight was good. I will get another chance perhaps in a few hours to see if it's still alive when not in sunlight and will try to grab some more telemetry.
I have a jpg screenshot of telemetry with the position info from earlier if anyone would like it.
73 James VK6FJA
On 27/08/2011 7:33 PM, Pete MI0VAX wrote:
Hi Carl,
I've seen this recently myself too.. On the occasions when it happened here over the UK, the bird "should" have been in high power mode, but after looking at telemetry it appears that it had switched into low power mode much earlier that than usual, from memory the footprint was only half in eclipse. Also noticed that before it cuts off that there is usually 10-15 or so seconds of a silent carrier. On another occasion it cut out halfway through a SSTV transmission - this I'm almost certain shouldn't have happened due to the way the firmware was written.
Perhaps a bad solar panel contributing to low voltage when approaching eclipse? I had noticed one of the panel temps was over 75c on several passes.
It certainly looks like there is some intermittent problems beginning to raise their head, lets hope it's not a steady decline in the bird's performance as gathering the SSTV pics, telemetry etc has been a very enjoyable change to the usual FM/SSB activity.
73 de Pete
Mi0VAX
On Sat, Aug 27, 2011 at 3:59 AM, Carl Rimmercfrimmer@gmail.com wrote:
I was having a really good pass gpong from my NW-SE and I had copied 6 frames of Telemetry and 5 frames of KURSK data when the bird just went silent. It never came back during this pass. It was the 08-27-2011 0241 UTC pass over Lake Erie. I am curious if anyone has heard it since than. That is probably the best I have copied it since day one. The frames
where
forwarded. The MET was 55' 33". Bat Voltage = 35.668; Bat Current = -16 ma. I've never heard it just go silent like that and not come back up.
Carl W8KRF _______________________________________________ Sent via AMSAT-BB@amsat.org. 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
Sent via AMSAT-BB@amsat.org. 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
participants (2)
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James McBride -
Pete MI0VAX