[Towertalk] Quads Yagis and contact static

[Chuck Counselman]

At 12:39 PM -0500 11/20/02, Pete Smith wrote:
>At 12:21 PM 11/20/02 -0500, you wrote:
>>An obvious _possibility_ is that all parts of all elements of a 
>>quad are grounded for DC, whereas one-half of the driven element of 
>>a Yagi (the half connected to the center conductor of a coaxial 
>>feedline) might not be.  An ungrounded antenna is noisy -- 
>>extremely so in my experience.
>>
>>What about _your_ Yagis?
>
>
>So then a yagi with a hairpin match across the feedpoint should be 
>quieter than one without?


Yes -- IF the explanation that I suggested as a _possibility_ is, in 
fact, the (chief) explanation.  However, I think that the suggestion 
of Michael Tope <W4EF@dellroy.com> regarding the vertically polarized 
component of a horizontally polarized quad antenna's radiation 
pattern vs. that of a horizontally polarized Yagi is an excellent 
one, worthy of examination.

As he points out, so-called horizontally polarized antennas typically 
have nontrivial response to vertically polarized radiation arriving 
from off-axis or "out of the plane."  E.g., a simple horizontal 
dipole does.

-Chuck, W1HIS