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Re: Re: no patches for offset dishes!!



Hi Joe,

Yes, certainly one should not avoid getting on mode-S because his equipment
or construction isn't "perfect" or "theoretically correct".  Its good to
know what the design concerns are so that if things aren't working well you
have some ideas to check out...but as you have demonstrated...it doesn't
require "rocket science"...just good old ham ingenuity!

I suspect that the primestars extra wide dish shape make help shield the
patch feed from ground noise, but when you have sufficient antenna gain and
noise figure/gain to see the satellite noise floor...any more improvement
is not going to buy anything!  By what I'm reading on the bb the primestar
makes a good choice for mode-S.

Looking forward to working the new "Alaskans"...does this mean we have five
active AO-40 stations up here now?

Ed, AL7EB

At 09:22 AM 7/12/02 -0800, WL7M wrote:
>I'm all in favor of making do with what you've got. If I had listened to the
>theorists regarding over illuminating offset dishes, I'd still be off the
>air on AO40. Instead, I scrounged a free Primestar offset dish that was
>being used to cover a stack of firewood, modified a few scrounged parts and
>pieces to make a mount, and bought a patch feed from James, G3RUH. A counter
>balance made from an old weight lifting set that I hadn't used in a decade
>made it all come together. 
>
>Although it may be over illuminated, I can hear AO40 extremely well. I feed
>the downconverted signal to my Icom 756Pro and I can "see" my uplink signal
>on the bandscope. That makes it easy to keep Leila from attacking me (reduce
>power until the uplink is below the beacon) and makes it easy to "find
>myself" when trying to zero beat someone calling CQ. 
>
>Rather than get involved in all the technicalities, I say go for it. I've
>tried a helix feed, but prefer the patch due to the greater structural
>integrity and "winter proofing", especially important here in the arctic
>climate of Alaska. I've had NO problems with either the patch feed or the
>Primestar surplus dish - and I'm operational on AO40 despite the "over
>illumination" theories.....you can see the pictures on my web site.
>
>73,
>Joe
>WL7M
>Fritz Creek, Alaska
>http://www.xyz.net/~joe
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