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Re: Got my 70 cm all mode - tips for SSB/CW birds?




----- Original Message ----- 
>From: "jonny 290" <jonny290@gmail.com>
>To: <amsat-bb@amsat.org>
>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

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