
March 11th 05, 11:05 PM
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A cardioid pattern has radiation in the 180 degree portion behind the feed
point
Regards
Art
"Gene Fuller" wrote in message
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Art,
Why not?
The cardioid pattern from a two-element array was reported back as least
as far as 1937, by the famous George H. Brown. In the ideal case (free
space, no losses, etc.) the radiation directly to the rear is precisely
zero.
If you add various real world effects then the back lobe is not precisely
zero, and this is shown in the ARRL Antenna Book referenced by Cecil.
A detailed description of all of this is in Kraus' Antennas, 2nd Ed., in
Chapter 11. He uses equations, and he does not mention coordination of
balloon patterns, so perhaps you have another new invention.
73,
Gene
W4SZ
wrote:
Yes Cecil, a cardioid pattern ,which cannot produce zero radiation at the
rear 180 degrees of the feed point.
Remember we started of with a figure 8 or two balloon pattern so for
total reversal of radiation the front lobe
must finish up as a perfect circle . Said another way, the two ballons
are merged thus making a larger single balloon
Best Regards
Art
"Cecil Moore" wrote in message
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wrote:
Richard
I looked thru The ARRL antenna book and I cannot find
any antenna let alone the two element phased array
that showed ZERO radiation to the rear of the feed point.
In my ARRL Antenna Book, 15th edition, page 8-6: Two phased
verticals with 1/8WL spacing and phased at 135 degrees shows
a perfect cardioid with zero radiation in a direction 180
degrees from the direction of maximum gain, i.e. directly
to the rear.
--
73, Cecil http://www.qsl.net/w5dxp
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