If you have a copy of YO it is very easy to see what effect element spacing
has on gain and f/b. If you optimize it on 15 for example and then move to
20 and keep the element spacing the same as it was for 15, you will see that
only changing element lengths will significantly compromise the performance
on 20, and vice versa. Also, I am not knowledgeable as to how the SteppIr
"optimizing" works. Does it merely tune every element for f/b or gain or
swr? With YO you can select what % to allocate for gain, f/b and feedpoint
impedance. Does SteppIR's program allow the user to do this? I honestly
don't know.
Bob W6TR
----- Original Message -----
From: "Jim Lux" <jimlux@earthlink.net>
To: "Bob Maser" <bmaser@tampabay.rr.com>; "Jan Erik Holm" <sm2ekm@telia.com>
Cc: <TOWERTALK@contesting.com>
Sent: Thursday, June 14, 2007 10:07 AM
Subject: Re: [TowerTalk] step away from steppir, Son
> At 06:29 AM 6/14/2007, Bob Maser wrote:
>>Surely you don't expect a 4 element on a 26 foot boom to be competition
>>for a 4 element SteppIR on a 32 or 34 foot , do you? I was just leveling
>>the playing field by taking the boom from a 205BA and taking away one of
>>the directors.
>>
>>The day that some company comes out with an antenna that can vary the
>>length of the elements and change spacings between the elements, then I
>>will consider buying one,
>
> Presumably this is because you want "optimum" spacing between elements
> (i.e. a boom length optimized for 20m will be too long on 10m, and vice
> versa)?
>
> What about a long boom with, say, 6 SteppiR elements spaced along it. On
> 10m, one just "turns off" the elements (retract them all the way, or
> change the length enough to eliminate the interaction) that are too far
> away and turn it into a "short boom".
>
> But, as a practical matter, I suspect that 4 adjustable elements on a
> longish boom can get very, very close to the performance (however you want
> to measure it) at a single frequency, as any other antenna of the same
> overall length. The challenge would be in specifying what you actually
> want from "performance".. is it gain, directivity, null placement, F/B,
> F/R, peak sidelobe level, integrated sidelobe level, or what?
>
> The only limit would be that the element spacing can't be more than,
> probably, 1/4-1/2 wavelength at the highest frequency of use.
>
> Jim
>
>
>
>
>
>
>
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