Jim, this subject came up in another context several weeks ago. Someone
said that the horizontal component of the noise signal seems to be
attenuated much more (by the ground?) than the vertical component. I
don't believe any explanation was given for the difference, if my memory
serves.
When I had a 40M vertical with four elevated radials and a 40M EDZ,
there was no doubt that the vertical was much noisier than the EDZ. Of
course, the vertical is omni directional while the zepp was
bidirectional. Nevertheless, the difference was dramatic even at a
relatively electrically quiet QTH.
73, Joe
K2XX
Jim Jarvis wrote:
> K8RI's post on this topic finally prompted me to raise a
> question that's been bothering me for some time.
>
>
> Why is powerline noise vertically polarized? Power lines are
> horizontal. Yes, it's true that there are vertical runs to
> ground, every few poles. But why is the noise assumed to be
> vertically polarized?
>
> Is it because that noise seems louder on our vertical antennas?
> Our UNBALANCED vertical antennas? If you read w1his's white paper
> on common mode chokes (yccc.com), you'll find that he's reduced the
> received noise levels substantially by decoupling the feedline.
> Perhaps I should have said our POORLY DECOUPLED UNBALANCED vertical
> antennas?
>
> George Henf, who founded GAP antennas, maintained that power line noise
> was horizontal, for the most part....and that his off center fed verticals
> were quieter than a dipole. I didn't challenge him, but the voyager and
> challenger models I put up to write his manuals, were no noisier than
> my 40m dipole @ 50'.
>
> I've pretty much accepted the common wisdom that manmade noise tended to
> be vertically polarized, since I became involved with ham radio in 1959.
> And in the ensuing years, I've heard the 'wisdom' often repeated...but
> never seen any studies supporting the belief.
>
> Anyone care to wade in?
>
> n2ea
>
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