[amsat-bb] EO-79 Transponder On Times - 21-Oct-2017

[Paul Stoetzer]

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 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
> 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