Re: [amsat-bb] EO-79 Transponder On Times - 21-Oct-2017
Hi Paul.
Thanks for the heads up on this. I'm away from home at present so not able to check on-air. Any transponder reports welcome.
Looking at the pass times, I think the schedule is OK. For example:
10/21/17 (all +/- 30 sec)
10.20.40 UTC exits eclipse over Antarctica. 10.56.40 UTC (+ 27 mins) Transponder turns on over Namibia at 24 degrees south Satellite heads North + passes over Africa and Europe with transponder on (perhaps!) 11.21.40 (25 min of on time) Transponder switches off just East of Iceland apx 64N
So schedule is fine, but perhaps the satellite has switched into a safe mode. I'll forward your mail to AMSAT-NL
Many Thanks
David G0MRF
I was curious about the status of EO-79 as the transponder has not been reported on in quite some time. AI6GS checked a pass this afternoon and heard nothing but the beacon.
As the transponder's operation causes the satellite to be power negative, the satellite is currently configured to charge for 27 minutes after coming out of eclipse and then the transponder is on for 25 minutes. When this schedule was put in place last year, this favored mid-latitudes, but due to orbital precession and the changing seasons, this is now seems to favor lower latitudes.
If anyone wants to check out the transponder today (21-Oct), I have calculated the following on times (by utilizing eclipse predictions in DK3WN's Illum).
0117 - 0132 0253 - 0318 0430 - 0455 0607 - 0632 0744 - 0809 0919 - 0944 1057 - 1122 1234 - 1259 1411 - 1436 1548 - 1613 1725 - 1750 1901 - 1926 1938 - 2003 2215 - 2240 2352 - 0017
73,
Paul, N8HM
David,
Thanks for the reply. The times I posted were sloppy work on my part. The keps I used were a month old and it really changed the calculations. Dumb mistake!
I'll check the transponder on my 15:58 UTC pass. With fresh keps, Illum shows that EO-79 will be in eclipse from 15:19 UTC - 15:42 UTC, so the transponder should come on at 15:59 UTC, one minute after my AOS and while the satellite is at 20° 16' N. The transponder should turn off at 16:24 UTC, when the satellite is at 65° 43' N.
So the schedule should be OK for northern hemisphere mid-latitudes, but it does seem that the satellite may have switched to safe mode. I'll follow up with my observations after that pass.
73,
Paul, N8HM
On Sat, Oct 21, 2017 at 6:58 AM, David G0MRF g0mrf@aol.com wrote:
Hi Paul.
Thanks for the heads up on this. I'm away from home at present so not able to check on-air. Any transponder reports welcome.
Looking at the pass times, I think the schedule is OK. For example:
10/21/17 (all +/- 30 sec)
10.20.40 UTC exits eclipse over Antarctica. 10.56.40 UTC (+ 27 mins) Transponder turns on over Namibia at 24 degrees south Satellite heads North + passes over Africa and Europe with transponder on (perhaps!) 11.21.40 (25 min of on time) Transponder switches off just East of Iceland apx 64N
So schedule is fine, but perhaps the satellite has switched into a safe mode. I'll forward your mail to AMSAT-NL
Many Thanks
David G0MRF
I was curious about the status of EO-79 as the transponder has not been reported on in quite some time. AI6GS checked a pass this afternoon and heard nothing but the beacon.
As the transponder's operation causes the satellite to be power negative, the satellite is currently configured to charge for 27 minutes after coming out of eclipse and then the transponder is on for 25 minutes. When this schedule was put in place last year, this favored mid-latitudes, but due to orbital precession and the changing seasons, this is now seems to favor lower latitudes.
If anyone wants to check out the transponder today (21-Oct), I have calculated the following on times (by utilizing eclipse predictions in DK3WN's Illum).
0117 - 0132 0253 - 0318 0430 - 0455 0607 - 0632 0744 - 0809 0919 - 0944 1057 - 1122 1234 - 1259 1411 - 1436 1548 - 1613 1725 - 1750 1901 - 1926 1938 - 2003 2215 - 2240 2352 - 0017
73,
Paul, N8HM
Ha! I just realized I had the wrong satellite selected when checking eclipses. Wow. I should stop trying to do this late in the evening or early in the morning!
So, selecting the right satellite, prior to my 15:58 UTC pass, I see the satellite will enter eclipse at 14:45 UTC and exit eclipse at 15:21 UTC. The transponder should turn on at 15:48 UTC, while it is at about 17 degrees south and turn off at 16:13 UTC, while it is at about 71 degrees north.
73,
Paul, N8HM
On Sat, Oct 21, 2017 at 8:50 AM, Paul Stoetzer n8hm@arrl.net wrote:
David,
Thanks for the reply. The times I posted were sloppy work on my part. The keps I used were a month old and it really changed the calculations. Dumb mistake!
I'll check the transponder on my 15:58 UTC pass. With fresh keps, Illum shows that EO-79 will be in eclipse from 15:19 UTC - 15:42 UTC, so the transponder should come on at 15:59 UTC, one minute after my AOS and while the satellite is at 20° 16' N. The transponder should turn off at 16:24 UTC, when the satellite is at 65° 43' N.
So the schedule should be OK for northern hemisphere mid-latitudes, but it does seem that the satellite may have switched to safe mode. I'll follow up with my observations after that pass.
73,
Paul, N8HM
On Sat, Oct 21, 2017 at 6:58 AM, David G0MRF g0mrf@aol.com wrote:
Hi Paul.
Thanks for the heads up on this. I'm away from home at present so not able to check on-air. Any transponder reports welcome.
Looking at the pass times, I think the schedule is OK. For example:
10/21/17 (all +/- 30 sec)
10.20.40 UTC exits eclipse over Antarctica. 10.56.40 UTC (+ 27 mins) Transponder turns on over Namibia at 24 degrees south Satellite heads North + passes over Africa and Europe with transponder on (perhaps!) 11.21.40 (25 min of on time) Transponder switches off just East of Iceland apx 64N
So schedule is fine, but perhaps the satellite has switched into a safe mode. I'll forward your mail to AMSAT-NL
Many Thanks
David G0MRF
I was curious about the status of EO-79 as the transponder has not been reported on in quite some time. AI6GS checked a pass this afternoon and heard nothing but the beacon.
As the transponder's operation causes the satellite to be power negative, the satellite is currently configured to charge for 27 minutes after coming out of eclipse and then the transponder is on for 25 minutes. When this schedule was put in place last year, this favored mid-latitudes, but due to orbital precession and the changing seasons, this is now seems to favor lower latitudes.
If anyone wants to check out the transponder today (21-Oct), I have calculated the following on times (by utilizing eclipse predictions in DK3WN's Illum).
0117 - 0132 0253 - 0318 0430 - 0455 0607 - 0632 0744 - 0809 0919 - 0944 1057 - 1122 1234 - 1259 1411 - 1436 1548 - 1613 1725 - 1750 1901 - 1926 1938 - 2003 2215 - 2240 2352 - 0017
73,
Paul, N8HM
participants (2)
-
David G0MRF -
Paul Stoetzer