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Re: Topband: "Magnetic" loops vs. pseudo-Brewster angle

To: "Sinisa Hristov" <shristov@ptt.yu>, <topband@contesting.com>
Subject: Re: Topband: "Magnetic" loops vs. pseudo-Brewster angle
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Wed, 10 Dec 2003 09:04:33 -0500
List-post: <mailto:topband@contesting.com>
> The picture shows full-strength radiation at zero elevation angle
> (in spite of antenna's vertical polarziation).
>
> The related text on the same page is:
>
>   "Its performance is not influenced
>    by the quality of the ground
>   (there is no pseudo-Brewster angle involved!)."
>
> I feel confused a bit.  Could this be so?

No. It cannot be so.

Magnetic loops are no different than any other antenna. As a matter of fact,
about 1/10th wavelength from a small magnetic loop the predominant field is
the ELECTRIC field. So the little thing people call a magnetic antenna
actually has a stronger electric component than magnetic component 50 feet
away on 160 and it remains that way out to perhaps a wavelength, where it
eventually is no different at all than any other antenna.

http://www.w8ji.com/radiation&fields.htm

This link shows the ratio of electric to magnetic field of a small "magnetic
loop" :

http://www.w8ji.com/emfield.gif

Another common myth is the loop can be shielded from time-varying electric
fields.

73 Tom


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