I would estimate that the principal loss is in the maximum f/b possible on a
given band. However, in a fixed yagi the maximum f/b only occurs at a given
frequency and drops off either side. Meaning that the StepIR can possibly beat
it at the band edges, or at the unfavored end, even on 10m where the f/b is
really a compromise.
For those whose upper lip goes into an uncontrollable quiver when the SWR meter
shows more than 1.1:1, the StepIR may be your answer. (Huge audience here...)
For those whose linear drops out on grid over-current when the SWR goes over a
certain level, the StepIR may be your answer.
For those who can get up exactly ONE rotatable antenna, and do contests, AND
love the WARC bands, the StepIR may be your answer.
We are getting into a year's worth of field experience. Have not heard any
Probably not a good idea any more to be dismissive of it's technology. Starting
to look like a keeper with a list of advantages which mate well with certain
circumstances, and only moderate disadvantages, which do not always apply.
And that from a Force 12 fan.
> From: Pete Smith <firstname.lastname@example.org>
> Date: 2003/05/20 Tue AM 11:46:27 EDT
> To: Towertalk@contesting.com
> Subject: Re: [TowerTalk] 4el SteppIR at Dayton?
> At 02:28 PM 5/20/03 -0700, W6TKV wrote:
> >Most of what I think I know about Yagi design came from spending time
> >with the K6STI's Yagi Optimizer design program. Clearly, any design is
> >always a tug-of-war between front-to-back, forward gain and SWR. I
> >realize the Steppir optimizes SWR vs. frequency, but I wonder what the
> >design parameters are for front-to-back and forward gain.
> >Has anyone thought much about this ... or asked?
> Sure -- it's a little like the old NASA line: "faster, better, cheaper --
> choose any two." If you can vary element length, but not spacing, then you
> will sacrifice either gain or F/B, or maybe both, compared to an optimized
> fixed yagi (depending on which band you are on). The same is true of
> trapped tribanders, though some of them have extra single-band
> elements. Arguably, if it will hold up mechanically, the SteppIR is a
> better solution than any trapped tribander with compromise spacing, because
> it adjusts within bands, where normal yagis must be optimized somewhere in
> the band and not elsewhere.
> A search of the Towertalk archive on contesting.com will turn up a useful
> series of messages about this.
> 73, Pete N4ZR
> The World HF Contest Station Database was updated 9 May 03.
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