> But given current distribution on a dipole, isn't it generally
> understood that drooping ends have relatively little effect?
"Drooping" ends result in a small amount of vertically polarized
radiation. Horizontally folded (or bent) elements result in some
degree of radiation at 90 degrees (think crossed dipoles) to the main
lobe. Since the side lobe structure in a yagi (or phased arrays -
consider what broadcast stations sometimes need to do to "detune"
nearby structures) is very sensitive, even a small amount of "off
axis" radiation can make a significant difference.
73,
... Joe, W4TV
On 3/20/2013 8:46 AM, Pete Smith N4ZR wrote:
But given current distribution on a dipole, isn't it generally
understood that drooping ends have relatively little effect? I guess
the Moxon is a special case, where the ends are brought close to each
other.
73, Pete N4ZR
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On 3/20/2013 7:27 AM, David Robbins wrote:
yes, in a classic yagi with straight and parallel elements that is
true... but when you bend or make the driven element not a simple half
wave dipole then it can have an effect on the pattern by itself.
Mar 20, 2013 01:18:45 AM, jim@audiosystemsgroup.com wrote:
On 3/19/2013 11:10 AM, Joe Subich, W4TV wrote:
They give the designer additional degrees of freedom with which to
control input impedance and side lobe structure.
I was with you until you said "side lobe structure." I don't claim to
know much a bout the design of Yagis, but I'm under the impression that
pattern is largely determined by the tuning and spacing of parasitic
elements. Am I wrong?
73, Jim K9YC
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