L. B. Cebik wrote:
>
> Having searched for a single antenna that will cover all of 10-meters with
> roughly equal gain, F-B, and SWR, I am currently working with possible
> LPDA designs. Translating these designs from calculating software, like
> LPCAD, into models of reasonable accuracy, and from there into something
> that can be built has turned out to have some interesting twists.
>
> So I have posted a work in progress, "A 10-Meter LPDA," at my site. The
> semi-frozen design has just about the same gain as a 3-element Yagi on a
> short (8') boom, used for the LPDA, with >20 dB F-B across the band and a
> flat SWR curve (once you introduce a matching section).
>
> Lots of questions remain in my head about the design, its construction,
> and related matters, but I thought that summing up what I have encountered
> so far might be useful. Remember not to translate anything relevant to
> the monoband LPDA to wide-band version covering many bands. I hope the
> notes are useful to someone.
>
> Look under the Upper HF antenna collection in the main index.
>
> -73-
>
> LB, W4RNL
>
> L. B. Cebik, W4RNL /\ /\ * / / / (Off)(423) 974-7215
> 1434 High Mesa Drive / \/ \/\ ----/\--- (Hm) (423) 938-6335
> Knoxville, Tennessee /\ \ \ \ / / || / (FAX)(423) 974-3509
> 37938-4443 USA / \ \ \ \ || cebik@utk.edu
> URL: http://web.utk.edu/~cebik/radio.html
>
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On the wideband LPDA that I have modeled the gain is usually equivalent
to a 3 element monobander. LPDA, I believe, are a bit difficult to
build.
What I suggest that you look at an OWA design. I modeled one and then
built it. Although it may be longer than you require it could be
shortened for less elements. It is 6 elements on a 36 ft boom. The SWR
is less than 1.1:1 from 28.0 to 29.6 Mhz. Bandwidth is 54 degrees and
F/b is 22 db. The feed point is 50 ohmns with an insulated dipole
connection.
It is up and working
Denis VE6AQ
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