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Old February 16th 10, 12:02 AM posted to rec.radio.amateur.antenna
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On Mon, 15 Feb 2010 08:01:18 -0800 (PST), Art Unwin
wrote:

I have not seen the like printed any where soto me it is good stuff.


This might offer a clue as to how such antennas are built:
http://ieeexplore.ieee.org/iel3/4812/13333/00608613.pdf?arnumber=608613
http://www.springerlink.com/content/g215405815642611/
Plenty more under IEEE Ants and Props search. Check if your local
library or college library has a subscription:
http://www.ieeeaps.org
http://ieeeaps.org/aps_trans/

When I model a polarization independent antenna the individual gains
confuse me as each of the individual gains are some what 3 db down
from the "total" gain. In other words "total" is not the addition of
all the polarizations gains.


If you use a circularly polarized antenna, and feed it a linearly
polarized signal (either vertical or horizontal) you'll see a -3dB
polarization mismatch loss.
http://www.antenna-theory.com/basics/antennapol.php

I find it very difficult to get my mind
wrapped around that fact. On the surface it would suggest that
competition types would benefit from a polarization independent
antenna.


Nope. According to my friends that do contesting, the major
requirement of an antenna is NOT to maximize the gain in all
directions. It's to reduce the gain to the side and back, where all
the other interfering stations are usually located. Directionality is
important or all you're going to hear are other local hams. A truely
isotropic antenna is fairly useless for contesting. (Note: I don't
do contesting).

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
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