Some discussions on the lists about competing designs for shortened
(half-element length) 40-meter 2-element beams suggested to me that
perhaps some folks are not familiar with the basic elements that go into
designing such antennas. So I made up a little tutorial, using the title
in the subject line, and put it at my web site.
The discussion is NOT about existing commercially made designs, but about
principles of design, including loading methods and their effects, notes
on in what ways where you make the measurements affects the operating
bandwidth, position of loads, and the relationship of performance peak
frequencies to antenna resonant frequency with respect to operating
bandwidth.
The idea is hopefully to give the reader some insight into what the design
goals of various antenna are and what design compromises may occur along
the way to meet an overal goal. With that in mind, and mixing in operator
needs and desires, more optimal purchase (or construction) decisions might
be reached. Short of that, perhaps the colorful graphs may be
entertaining.
I hope the notes are useful to some.
-73-
LB, W4RNL
L. B. Cebik, W4RNL /\ /\ * / / / (Off)(423) 974-7215
1434 High Mesa Drive / \/ \/\ ----/\--- (Hm) (423) 938-6335
Knoxville, Tennessee /\ \ \ \ / / || / (FAX)(423) 974-3509
37938-4443 USA / \ \ \ \ || cebik@utk.edu
URL: http://funnelweb.utcc.utk.edu/~cebik/radio.html
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