[amsat-bb] Re: ao27.org possible schedule error?

[Patrick STODDARD (WD9EWK/VA7EWK)]

Hi Sam!

>   From what I see, the schedule on ao27.org seems to be 8-10 mins off
>  from actual time. The bird doesn't seem to have changed schedule at all.
>  Can anyone else confirm this?

Your observation appears to be correct.  I have seen this about a month or
so after the satellite gets a new schedule uploaded to it.  It appears to be
a glitch on the web site.  AO-27 should be turning on during afternoon
passes when it crosses approximately 29 degrees North latitude.

Do you have the AO-27 Satellite Scheduler program available from:

http://www.cs.rit.edu/~cjh9783/programs/satsched.php

It requires the Java Runtime Environment on your computer, and there are
versions that will run on any OS with Java or one specifically for Windows
(still needs Java installed).  This will get you closer to the schedule on the
satellite, keeping in mind the statement on http://www.ao27.org/ that the
onboard clock is fast by 0.7 seconds/day from when the last schedule
was put into effect (currently, from 8 March 2008).

Comparing the program with the web site, it appears there is a discrepancy
of around 7 minutes (not accounting for onboard clock issues).  If you can
get the program to determine the onboard schedule instead of using the
web site, that would probably be a good thing.  Or use your program to
determine approximately when AO-27 crosses 29 degrees North, to get an
approximate idea when the satellite's repeater should be available.

73!



Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/