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Re: Circular Polarity



James,

This [helix antenna designs] was a topic on this list about two weeks ago.
Hopefully someone who kept the info will respond.  

As far as 10 GHz goes, I would discourage you from making a helix.  A
better antenna would be a small dish fed by a horn.  Instead of circular
polarization, I would make a circular horn [3/4 inch dia] with two coax
probes at 90 degrees and chose which ever one [polarization] that gives the
strongest signal.  A 60cm dish will produce a signal 20 dB over noise if
your preamp has a noise figure of 1.5 dB.  An 18 inch DBS offset feed dish
is only 3 dB less gain and can be gotten from mcm electronics for around
$30.  That's what I plan to use [well, I also have a 2.5m dish for 10 GHz
with a .79 dBNF preamp].

Ed

At 11:48 PM 12/29/00 -0500, you wrote:
>
>Anyone have or know of a program to help design helical antennas?
>
>I'd like to build one for the 1.6 Ghz GEOS satellites, plus a 2.4 Ghz and
>maybe 10ghz for Oscar work.
>
>
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