[amsat-bb] Re: L and S-band Options
Alan P. Biddle
APBIDDLE at UNITED.NET
Sat May 8 11:34:12 PDT 2010
Mode-L is not authorized for transmission FROM a spacecraft, only TO one.
So you only need TX capability. Of course the rigs you mentioned will give
you the needed TX capability. A cheaper way would be to find a used
transverter. Note that unless it was designed for satellite use, it will
probably need new crystals and tuning. In principle an HT which covers
mode-L, combined with an amp and good antenna, would work for an uplink.
However, the Doppler shift is so large, and changes so rapidly, that you
need computer control. It CAN be done without that, but it is painful for
you, and more painful for the people you might work.
A helical antenna, easily made and uncritical, can be made for either mode-L
or mode-S for a few dollars. Likewise, there are still a few of the old MDS
converters around. AO-51 has a very loud downlink, and can even be heard on
a simple patch antenna without a dish, or a short Yagi.
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Guy Brauning
Sent: Saturday, May 08, 2010 11:09 AM
To: amsat-bb at amsat.org
Subject: [amsat-bb] L and S-band Options
Thanks for reading this message. I know there has been a lot of information
on the BB over the past couple of years about operating L and S band on
AO-51; however, I was focused on V/U at the time and I didn't make notes of
the information. Now I would like to experiment with these two bands and I
am looking for some recommendations to get started. Is the Alinco DJ-G7T a
viable option for receiving the AO-51 L-band downlink (Pricey at $320.00 but
it does cover 3 satellite bands with advertised full-duplex capability)? If
not (and ruling out the more expensive (and effectively non-portable)
transceivers.. TS-2000 / IC-910H, etc.), what would be the least expensive
way to have receive capability on 1.2 Ghz... a down-converter perhaps? (I
currently have a Yaesu FT-60R dual band HT and a Yaesu FT-817D along with
the Arrow and ELK antennas for V/U) Also, what are some options for
homebrew 1.2 Ghz antennas (I do not have sophisticated test equipment and my
"Skills" are minimal)? On to 2.4 Ghz.... what are some options for
inexpensive 2.4 Ghz down-converters (As a reference..I do not consider the
SSB UEK-3000 inexpensive at $500.00) and homebrew antennas? I would like to
be able to experiment with handheld / portable gear in the yard to gain some
experience with these two bands.
guyjeanbraun at comcast.net
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