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

[David G0MRF]

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