I tend to agree strongly with Stuart's comments, especially on the area of
concern regarding holding up in the WX. I lived in S. FL for several years
and found the most metals would fail sooner than latter when exposed to the
elements of Mother Nature.
And yes, verticals do require a good ground system. This is in spite of
what some say about not needing a ground radial system. Then there is the
discussion of what comprises a good ground system. The poorer the soil
conductivity the more radials and thus better ground system required.
My bet for all around operating, a simple 1/2 wave center fed wire for the
lowest frequency. Feed it with good balanced feed line from a balanced
tuner. Avoid the 4:1 balun syndrome. Or a choke balun made of some good
quality RG-213 coax does an outstanding job of getting from a unbalanced
tuner output to a balanced feed line.
73
Bob, K4TAX
.
----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: "Ken & Linda Burrough" <w8keb@1st.net>; <tentec@contesting.com>;
<dock0evz@earthlink.net>
Sent: Friday, October 10, 2003 12:48 PM
Subject: Re: [TenTec] Opinions on StepIR vertical
> I looked carefully at the StepIR products cutaway model at Ham Com
> Arlington. It is an impressive mechanical mechanism. However, like
> anything mechanical, I question how well it would hold up in a Northern
> climate. There is no real advantage to continuous adjustable antenna.
In
> spite of ham folklore, it does not matter if you are operating exactly at
> the resonant point of your antenna or at 1.5 to 1 SWR somewhere else on
its
> curve. With good quality feeder, and a transmatch, your feedline loss
does
> not have to be enough to notice. In the StepIR you trade off issues of
trap
> verticals for issues of a complex tracked drive, and the electrical motor
> system you have to keep working through heat and cold. At least with
stub
> decoupled verticals like the Gap series, you do not have any traps and
thus
> no LC trap losses. The Titan has full band coverage on all bands, 40 to
> 10, and mine covers more than 100 kHz on 80.
>
> The StepIR does bring the ability to see that you do not work any more DX
> with a continuously resonant vertical than with a well designed
broadbanded
> multi band vertical such as the stub decoupled vertical dipoles.
>
> What I am saying is there is no free lunch. What you gain in one design
is
> countered by its increased power drain and mechanical complexity. It
would
> be fun to have just to say you have done it; but at the end of the day; it
> is the further field area of your antenna site, out into the Fresnel Zone
> that will affect how well your vertical works, and that distant area is
only
> improved if you move to one that is better.
>
> In the case of their beams, I wonder how well the idea works since the
> length of elements is interactive with optimum spacing of elements, and if
> you continue to adjust elements length, how does that affect your beam
> pattern?
>
> Everybody needs a selling point, as with modern modeling the basic
antennas
> designs are well represented among the manufacturers. You have to
innovate
> with something, and continuous resonance is an interesting feature.
> 73
> Stuart
> K5KVH
>
>
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>
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