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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