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Re: 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,


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