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Re: "Trash Can" or steel drum dish antennas



The conical horn very effectively shields the feed point, the 
parabolc elbow surface corrects the phase of the wave and thereby 
reduces the sidelobes.

John


>I suspect that mechanical convenience is a big factor in using this 
>design, both
>when put in a fixed vertical position on a tower, or in a horizontal steerable
>position on the ground.
>
>Doug
>NA1DB
>
>At 01:41 PM 12/4/01 , you wrote:
>
>  > > > As an aside, anyone ever heard of a "cornucopia" antenna?  Some of the
>  > >  > old long-haul analog microwave sites run by the old AT&T 
>still have some
>  > >  > up.  They are generally a cone pointing up with an "elbow" 
>opening that
>  > >  > opens to the horizon.  Those have even better sidelobe/backlobe
>  > >  > performance.  I have some pictures in old textbooks; they appear to be
>  > >  > one of the original radio astronomy antennas.  And now 
>they're all dark;
>  > >  > someone needs to pull one down and fire it up!!
>  >
>  >I believe you are refering to what I know as a "conical horn". Check:
>
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