[amsat-bb] EO-79 Transponder On Times - 21-Oct-2017
n8hm at arrl.net
Sat Oct 21 13:01:19 UTC 2017
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.
On Sat, Oct 21, 2017 at 8:50 AM, Paul Stoetzer <n8hm at arrl.net> wrote:
> 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.
> Paul, N8HM
> 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
More information about the AMSAT-BB