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Re: S-Band Antenna Comparisons, etc.



On Mon, 8 Jan 2001, KB7WW Art Moe asked about linear reflectors:

> Bob and all,
> Does this not depend on the frequency and the wire spacing ?????
> Art, KB7WW

Nope.  To reflect both polarizations you need a mesh.  Not a linear array
of parallel wires no matter how close.   Unless they are connected.  At
the frequency where these connections are close (say 0.1 wavelength) then
these connections will also begin to reflect the other polarization...

> Bob Bruninga wrote:
> > 
> > > The reflector is just that -> it reflects RF power to the feed.  So it
> > > matters not which way the reflector grill runs.  As Dave Tipton pointed out,
> > > what matters is the feed.
> > 
> > I gotta jump in here... a reflector of parallel wires will only reflect an
> > electromagnetic field of the same polarization.  To the other
> > polarization, there is a null...  This fact is used all the time in
> > microwave work to enhance one plarization over another, or to null out
> > one, or to allow one to pass through and the other to be reflected...
> > etc..
> > 
> > de WB4APR, Bob

de WB4APR@amsat.org, Bob


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