Apparently, the take-off-angle:

http://www.para.org.ph/membersarticl...Slim%20Jim.htm

I have *serious* doubts about the analysis in that article.

I believe that the author's assumption that splitting the radiator
current in half, and running it through two parallel elements, has the
effect of increasing the gain and dropping the takeoff angle is
incorrect.

The analysis I've read on Cebik's web site of J-poles of various sorts
seems to make no mention of this alleged effect. Nor have I seen it
discussed in writeups of folded dipoles.

If increasing the gain of a half-wave dipole were as easy as that,
it'd be a lot more popular a technique, and much better known.

I believe that a "slim jim" might have a slightly wider bandwidth
and/or lower resonant frequency than a single-wire J-pole of the same
dimensions, but more gain? Unless somebody's got independent evidence
of this (measurements or a good NEC model) I'd take it with a
good-sized grain of salt.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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