Michael Tope wrote:
> Steve,
snipped....
> to do for a fixed element length yagi. It could very well be that
> a SteppIR can eek out an extra .5dB of forward gain when
> you get rid of the bandwidth constraints.
> 73 de Mike, W4EF................................
I would tend to agree more with Steve and Dave on this matter. There
is simply no way in the world ( short of an advanced antenna range )
to determine how an individual element in the SteppIR might be changed
to get additional gain.
As an example, the element length and spacing on my 5 element
monobander on 20 * and its twin on 15 ) is so critical I had to use
millimetres for the tips and element spacing. As it stands right now,
the antenna models at 50 +/- j0, and shows 15.93 dbi of gain with 55.6
db F/B. All this modelling was done with EZNEC. (DOS and Windows
versions) I can vary the spacing of the 3rd director ( or length ) and
that pattern goes to hell in a hand basket.
Admittedly, 55.6 db F/B is excessive, but I have always gone with the
theory that you
shoot the "juice" in the desired direction at all costs.
As an after thought, I firmly believe that antenna height is the
overall controlling factor. As some of the guys have pointed out, my
TH-11 at 55' will whip the snot out of that big 20 under 5000 miles.
Very interesting thread.
73
Ed
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