[Wswss] [VHF] 1296 dish

[Chris Boone]

You don't want the gap in the holes to be 1/4wl at least....I would stay
1/8wl if possible or smaller....
I don't think you would lose much if any gain by going to 1/4wave
spacing..the Mark style dishes I use on 900MHz STLs for radio stations have
wide spacing (less than 1/4wl though) and work just fine!

Chris
WB5ITT

-----Original Message-----
From: owner-vhf at w6yx.stanford.edu [mailto:owner-vhf at w6yx.stanford.edu] On
Behalf Of Len Gwinn
Sent: Sunday, September 06, 2009 8:03 PM
To: wswss at mailman.qth.net; PNWVHFS; vhf at w6yx.stanford.edu
Subject: [VHF] 1296 dish

Hi all,

I have been using a 10 foot TVRO dish on 1296.  It works great BUT BUT,  I
have a question.

Situation.---The dish presently has small spaced wire mesh for its surface.
OK, that is smooth.  BUT when I get high winds it is more like a solid
surface
I have been told.  I am getting some structure damage from the high wind
vibration where the dish is braced back into the house at the center of the
dish.  I have tried turning the dish sideways into the wind but no change in
conditions.  Wind in the winter runs up to 70 mph  !!

Question---How much do I lose in gain--if at all--if I change the dish
surface
to half inch hardware cloth/wire/screen,   OR to one inch similiar
material???
This should greatly cut down any vibration/acting like a solid dish ie, wind
load would be much much less.  Does this also maybe allow more power to go
thru the dish thus affecting anyone behind the dish  ???

I am planning on moving up to 300 watts output to the dish and would rather
use the dish than a 22 element beam !!!

Any ideas or help  ?? or places to go read about it  ??

Thanks

Len  WA6KLK
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