[amsat-bb] Re: ARISSat daylightpower recovery time
I agree with this observation here at IO92NL. Arissat-1 does not switch on immediately when in sunlight, I have missed several passes this morning and in the last few days. I am just waiting for what the MET is announced (voice tlm) as at 1032 utc AOS (coming up) and will backtrack to how long she has been in sunlight. The difference ought to tell us the latency. 73 de andy G0SFJ ___ 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
[amsat-bb] Re: ARISSat daylightpower recovery time
Hi Dick, I think the delay is the result of the timer circuit that was mandatory for its release during the spacewalk from the ISS. The delay timer had to be there, and there is no way to defeat it, so it just has to run its course every time it exits eclipse. As you have probably noticed, the orbit is changing (precessing?) so for a week or two conditions are favorable in your QTH, then it changes so that the bird spends much of the overhead time either in eclipse, or just after eclipse and the bird isn't transmitting. The good news is that it will "come around again" so that conditions are favorable at a given QTH. As an admitted telemetry nut myself, it's painful to know the bird is at high elevation over my QTH, yet no telemetry is being sent or received...but it'll come back around :) The truly painful days will be when it's re-entering...doubt we'll get press like UARS! 73, Mark N8MH At 10:35 AM 9/24/2011 +0100, Richard Ferryman wrote: >Although I have severely limited satellite visibility I have been copying >telemetry from ARISSat1 for some weeks. I live in a valley surrounded by >chalk hills and cliffs over 100 metres higher than me so my visible horizon is >+12 degrees to +18 degrees at best. Also my 3+3 element short crossed yagi >and rotator are in the attic! This worked beautifully when the satellite >batteries held up and now when ARISSat is powered up. However I notice it can >take 10 minutes or more from the time the satellite enters sunlight until the >system bursts into life. At present this means loss of telemetry at this >location when ARISSat is over the Atlantic, and even on overhead passes if it >has been in sunlight for less than 10 minutes. >Question is why it takes ARISSat so long after entering sunlight before it >starts transmitting? Surely if the batteries have failed high resistance the >voltage should be up within seconds of entering sunlight. >Dick G4BBH >___ >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
[amsat-bb] Re: ARISSat daylightpower recovery time
Did not catch the second voice digit! "MET is One shh" But satellite is switched on. On 18 september the voice announced MET (19 and 21) equalled the time in sunlight, as I have calculated back using today's keps, within 1 minute. Allowing for keps 1 week old I think the MET is in fact announcing the time the satellite "wakes up" as she enters sunlight, but there are no fm transmissions at that time. The latency is up to 10 -19 minutes (if I had the second digit I could be more precise,hi!!) From: andy thomas To: amsat Sent: Saturday, 24 September 2011, 11:24 Subject: Re:ARISSat daylightpower recovery time I agree with this observation here at IO92NL. Arissat-1 does not switch on immediately when in sunlight, I have missed several passes this morning and in the last few days. I am just waiting for what the MET is announced (voice tlm) as at 1032 utc AOS (coming up) and will backtrack to how long she has been in sunlight. The difference ought to tell us the latency. 73 de andy G0SFJ ___ 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
[amsat-bb] Re: ARISSat daylightpower recovery time
Based on posted observations, I have come to the conclusion that the satellite's MET comes up at either 0 or 1 when the satellite turns on, after the 10-or-so minute delay after entering sunlight. Depending on what mode it thinks it should be in, I suppose it's possible that it might in fact be in one of those power saving quiet periods at that time, and only be heard a few minutes later. Entering sunlight is not a knife-edged event in orbit; there's a short ramp in power, so (playing arm-chair engineer here) I expect it would be in low or emergency power mode for a short while. Greg KO6TH > Date: Sat, 24 Sep 2011 11:49:36 +0100 > From: andythomasm...@yahoo.co.uk > To: amsat-bb@amsat.org > Subject: [amsat-bb] Re: ARISSat daylightpower recovery time > > Did not catch the second voice digit! "MET is One shh" But satellite is > switched on. > > On 18 september the voice announced MET (19 and 21) equalled the time in > sunlight, as I have calculated back using today's keps, within 1 minute. > Allowing for keps 1 week old I think the MET is in fact announcing the time > the satellite "wakes up" as she enters sunlight, but there are no fm > transmissions at that time. The latency is up to 10 -19 minutes (if I had the > second digit I could be more precise,hi!!) > > From: andy thomas > To: amsat > Sent: Saturday, 24 September 2011, 11:24 > Subject: Re:ARISSat daylightpower recovery time > > > I agree with this observation here at IO92NL. > > Arissat-1 does not switch on immediately when in sunlight, I have missed > several passes this morning and in the last few days. > > I am just waiting for what the MET is announced (voice tlm) as at 1032 utc > AOS (coming up) and will backtrack to how long she has been in sunlight. The > difference ought to tell us the latency. > > 73 de andy G0SFJ > ___ > 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
[amsat-bb] Re: ARISSat daylightpower recovery time
Interesting My observations last weekend show that MET matches the satellite entering sunlight: 18 September calculated Time into sun: 1004 utc Time of obs (announcement): 1023 utc Voice announced MET: 19 calculated Time into sun: 1136 utc Time of obs: 1158 utc Voice announced MET: 21 maybe the voice tlm MET isn't accurate either! howver I calculated the time of the entering sunlight using the keps of 24/9, not the keps of 18/9, via satpc32. 73 de andy g0sfj From: Greg D. To: andy thomas ; amsat Sent: Saturday, 24 September 2011, 17:46 Subject: RE: [amsat-bb] Re: ARISSat daylightpower recovery time Based on posted observations, I have come to the conclusion that the satellite's MET comes up at either 0 or 1 when the satellite turns on, after the 10-or-so minute delay after entering sunlight. Depending on what mode it thinks it should be in, I suppose it's possible that it might in fact be in one of those power saving quiet periods at that time, and only be heard a few minutes later. Entering sunlight is not a knife-edged event in orbit; there's a short ramp in power, so (playing arm-chair engineer here) I expect it would be in low or emergency power mode for a short while. Greg KO6TH > Date: Sat, 24 Sep 2011 11:49:36 +0100 > From: andythomasm...@yahoo.co.uk > To: amsat-bb@amsat.org > Subject: [amsat-bb] Re: ARISSat daylightpower recovery time > > Did not catch the second voice digit! "MET is One shh" But satellite is > switched on. > > On 18 september the voice announced MET (19 and 21) equalled the time in > sunlight, as I have calculated back using today's keps, within 1 minute. > Allowing for keps 1 week old I think the MET is in fact announcing the time > the satellite "wakes up" as she enters sunlight, but there are no fm > transmissions at that time. The latency is up to 10 -19 minutes (if I had the > second digit I could be more precise,hi!!) > > From: andy thomas > To: amsat > Sent: Saturday, 24 September 2011, 11:24 > Subject: Re:ARISSat daylightpower recovery time > > > I agree with this observation here at IO92NL. > > Arissat-1 does not switch on immediately when in sunlight, I have missed > several passes this morning and in the last few days. > > I am just waiting for what the MET is announced (voice tlm) as at 1032 utc > AOS (coming up) and will backtrack to how long she has been in sunlight. The > difference ought to tell us the latency. > > 73 de andy G0SFJ > ___ > 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
