When setting up to work AO-27 yesterday I noticed that the schedule on ao27.org indicated it would be turning on later than normal, with the bird up in Canada. I went out to catch the pass a minute before the scheduled on time and found that the bird was already on. It switched to TLM within a minute and then turned off.
Today I went out for the 2022 pass before my tracking program's indicated AOS. The bird was on as it rose and it stayed on for a good 6-7 mins before going to TLM. When I got back in after it turned off, ao27.org listed analog as the current mode, with over 5 minutes remaining.
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?
73, Sam KC2LRC Syracuse, NY - FN13
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/
Since my son graduated from RIT last May, he may lose the hosting of the program on the rit.edu site at any time. Just in case, I am now hosting the program at http://home.earthlink.net/~ka3hsw/ao27/ as well.
Enjoy!!!
George, KA3HSW
----- Original Message ----- From: "Patrick STODDARD (WD9EWK/VA7EWK)" [email protected] To: [email protected] Sent: Tuesday, April 29, 2008 12:58 AM Subject: [amsat-bb] Re: ao27.org possible schedule error?
[snip]
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
participants (3)
-
George Henry -
Patrick STODDARD (WD9EWK/VA7EWK) -
Sam KC2LRC