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From: "jonny 290" [email protected] To: [email protected] Sent: Monday, December 10, 2007 5:20 PM Subject: [amsat-bb] Got my 70 cm all mode - tips for SSB/CW birds?
I'm looking at VO-52 and AO-7, from the AMSAT page.
Are these birds active at all? Can I expect QSO's on afternoon/weekend passes, or will I need to set up skeds?
AO-7, given continuous sunlight as it is lately and for many weeks yet, will be in Mode-B(432.15 up/145.95 down) for 1/2 the time, and works well in both modes considering it's age ;) . Just don't use too much uplink power or you'll drag down it's solar panels and ruin everybody else' QSO's. The batteries are completely gone. Most passes, I hear at least one SSB QSO during "prime-time", and all day on weekends, and CW almost as often. I can't say much for how much goes-on during the other half of the time for Mode-A(145.9 up/29.45 down) because my receiving setup is nearly deaf on the 10M downlink.
There's a great website http://www.planetemily.com/ao7/main.php that the "AO-7 afficionados" use continuously for logging activity on this satellite, and it's also got some great statistics and other info about her. From the logs, you can see clearly that the mode a/b switchover timer activates right around 02:00UTC every day running each mode for 24 hours at a time. This will work untill the satellite has an eclipse, where it starts up in a default of Mode-B, the counter is reset every time the power is off(eclipse). There's even a chart that shows eclipses and how the satellite is sometimes very close to being perfectly sun-synchronous. Try calling on ssb, higher than the middle of the passband, about 145.953, or CW lower than 145.950.
VO-52 is a great one with two nearly identical transponders. one has 60 KHz of bandwidth, and the other has 50 KHz. They both have the same center frequency for uplink(145.900), and downlink(435.25), so the only possible way to know which one is on, is to find which beacon is on. The 60KHz unit (built in India) is 145.936 carrier. The 50KHz one (built in Holland) is 145.86 CW. You will find activity on this satellite during the evening hours of prime-time and on weekends anytime. Try calling in the middle of the passband(145.9), or higher for ssb, lower for CW. I have yet to work VO-52 on ssb, because of some problem with my transmitter, and I need to learn CW and get a proper key for CW!
I hope this helps, Auke