[amsat-bb] Re: AO-51 Mode S Antenna question

George Henry ka3hsw at earthlink.net
Sat Apr 5 19:44:25 PST 2008

----- Original Message ----- 
From: "Ronald Nutter" <rnutter at networkref.com>
To: <amsat-bb at amsat.org>
Sent: Saturday, April 05, 2008 10:02 PM
Subject: [amsat-bb] AO-51 Mode S Antenna question

>I have one of the K5GNA modified downconverters with the corner
> reflector attached.  Since starting to set my satellite station back up,
> this is one area that I hadnt addressed.  I have my antennas mounted to
> a Channel Master rotor on a commercial TV tripod.  The antennas are
> angled at about 25 degrees because of some ground clutter, trees, etc
> that I have to shoot over to get to the satellites.
> With this setup, can I mount the Mode S downcoverter and have a
> reasonable chance at getting it to work or should I look at some type of
> patch antenna to get better signal picket ?  Is mode S a little less
> unforgiving so that I have to have it more directed at the satellite
> than I can get away with on my current VHF/UHF antenna setup ?
> Thanks,
> Ron

The mode S downlink on AO-51 is pretty easy to receive with a corner 
reflector without critical aiming:  there's a video somewhere of Drew (I 
think...) making contacts with just such a downconverter/corner reflector 
combo just laying on its side on the roof of his car...  The real trick is 
the doppler:  3x as much as on 70 cm!  CAT tuning is a must.


George, KA3HSW

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