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Fw: Helix Feed for a Dish



Hi All:

RE: "Is a 2 1/4 turn helix sufficient for use with a .9 meter, center-focus
dish
with a focal length of .45?"

I screwed up.  I should have said that the F/D is .45, NOT the focal length.

73,

Woody
KJ4SO


----- Original Message -----
From: "Woody" <kj4so@bellsouth.net>
To: <amsat-bb@AMSAT.Org>
Sent: Tuesday, June 05, 2001 22:36 PM
Subject: Re: [amsat-bb] Helix Feed for a Dish


> Hi All:
>
> There have been many very interesting messages on the BBS lately on the
use
> of a "cup" style reflector on a helix dish feed antenna to reduce the
> sidelobes and thereby reduce noise pickup on S-band dishes.
>
> However, I have not seen any discussion on the size and depth of the cup
> reflector.  Has anyone experimented with various diameter cups as well as
> the depth of the cup?  The diameter and depth of the cups would be very
> helpful to many people, myself included.
>
> Does the diameter and depth of the cup change between feeds used for an
> off-set feed dishe, versus a center-focus parabolic dishe?
>
> Is a 2 1/4 turn helix sufficient for use with a .9 meter, center-focuse
dish
> with a focal length of .45?
>
> Thanks & 73,
>
> Woody
> KJ4SO
>
>
>
> ----
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>


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