[amsat-bb] EO-79 Transponder On Times - 21-Oct-2017
n8hm at arrl.net
Sat Oct 21 12:50:09 UTC 2017
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.
On Sat, Oct 21, 2017 at 6:58 AM, David G0MRF <g0mrf at 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
> Satellite heads North + passes over Africa and Europe with transponder on
> 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
> Paul, N8HM
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