Re: SETI Newbie questions about the Fresnel Zone Plate Antenna.

Henry Wallace (
Wed, 28 Jul 1999 12:17:52 -0500

Hello Bryce:

The phase of the incoming signal is expected
to be constant ( flat ) across the entire antenna.
That is, as long as the antenna is pointed at
the source. If the antenna is rotated away from
the source, there is a linear phase-shift across
the aperture of the antenna.

A good book, with a neat explanation, is

Fundamentals of Optics, by Jenkins & White.

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> From: Bryce Anderson <>
> To:
> Subject: SETI Newbie questions about the Fresnel Zone Plate Antenna.
> Date: Wednesday, July 28, 1999 11:46 AM
> After struggling with my physics book for a couple of hours, I still
> don't understand how this antenna is supposed to work. Does it act as
> a diffraction grate? Does the incoming signal need to be phased in
> order for it to work? I'm also wondering if it would be possible to
> design the feedhorn in such a way as to get the same phasing effect on
> a parabolic scope.
> ===
> Bryce Anderson
> In a thousand years, computers are going to look back and
> wonder why they ever put up with us.
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This archive was generated by hypermail 2.0b3 on Sun Aug 01 1999 - 16:28:47 PDT