[amsat-bb] Re: back on the birds after 15-year absence - want tips on antenna system
glasbrenner at mindspring.com
Mon Dec 28 18:27:25 PST 2009
Welcome back! I'll try to answer what I can.
> (1) RHCP for the V and U Yagis? Any reason to have switchable polarity?
Some LEOs have different circularities for different transmitters. For
example, AO-51 has both LHCP and RHCP on 70cm. The sense can also change
during a pass depending on spacecraft orientation and squint. Switchable
polarity is well worth it in my opinion.
> (3) Will next gen ham satellites have S-Band downlinks?
Yes, and AO-51 has an S downlink now, usually about 1 week a month. P3E
and others will have S.
> (4) Will next gen ham satellites have L-Band uplinks and/or downlinks?
Yes, and AO-51 and CO-65 use L now also. Kiwisat and P3E will have L also.
> (6) Are these the satellites currently available for 2-way QSOs? AO-7, AO-27, AO-51, SO-67 & HO-68. Did I miss any?
Off the top of my head, add ISS, SO-50, VO-52, FO-29 (due to return
soon), NO-44 sometimes, CO-65 for a real digital challenge. Lots of
one-way cubesats that can be fun too.
> (7) Any pattern to when AO-7 is in Mode A and Mode B?
Right now the satellite is in 24/7 illumination, and the onboard timer
switches modes every 24 hours or thereabouts. Check
http://oscar.dcarr.org/ as a quick way to figure out which one is on
right now. When it returns to eclipses, it generally favors B and only
works while illuminated.
I hope that helps. Joining AMSAT if you're not already a member is a
good way to support the program, and there is always something
interesting in the AMSAT Journal. There are several active ops in your
immediate area, including a BOD member; they may chime in. See ya on the
73, Drew KO4MA
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