TT:
It seems to me that the main advantage of the SteppIR concept is that
the operator gets a warm-and-fuzzy feeling about SWR everywhere he decides
to operate. Other than that, it seems like it's a compromise across the
bands except for the narrow frequency range where F/B or forward gain is
optimal.
The LPDA, OTOH, is also a compromise - in gain vs boom length. One
gets the same warm-and-fuzzy feeling about SWR, but with no moving parts to
worry about, and with somewhat more consistent F/B and forward gain across
its design range.
Nothing's ever easy, is it?
73 de
Gene Smar AD3F
-----Original Message-----
From: Jon Ogden <na9d@speakeasy.net>
To: Jim@ShawResources.com <Jim@ShawResources.com>; Dino Darling
<k6rix@arrl.net>; towertalk@contesting.com <towertalk@contesting.com>
To: <towertalk@contesting.com>
Date: Thursday, November 14, 2002 2:01 PM
Subject: Re: [Towertalk] LPDAs...
>on 11/14/02 10:51 AM, Jim Shaw at Jim@ShawResources.com wrote:
>
>> QUESTION: Instead of an LPDA, why not use a 3 element SteppIR antenna?
>> Don't they cover all frequencies continuously from 13.9 to 30 MHz? Isn't
>> that similar to the design goal of an LPDA? Seems like a SteppIR should
>> easily cover MARS frequencies in that range. Just asking cause I have no
>> first hand experience with either and LPDA or a SteppIR.
>
>The SteppIR antenna has been discussed here ad nauseum. My main issues
with
>the SteppIR:
>
>1.) Mechanical. How reliable is it? What about condensation inside the
>motor, etc. and then what about when all that moisture freezes? It would
>just suck the royal you know what to have your antenna freeze up in the
>middle of January when chasing that rare DX.
>
>2.) Only 3 elements.
>
>3.) As others have said, the element spacing is only optimized for one
band.
>
>4.) It's expensive for just 3 elements.
>
>While the SteppIR I would think certainly have a lot going for it over a 3
>element Yagi, I don't think its performance can compare with some of the
>bigger multiband Yagis.
>
>It's an interesting antenna and for some people and some installations,
>perhaps quite a good one.
>
>73,
>
>Jon
>NA9D
>
>-------------------------------------
>Jon Ogden
>NA9D (ex: KE9NA)
>
>Citizen of the People's Democratic Republik of Illinois
>
>Life Member: ARRL, NRA
>Member: AMSAT, DXCC
>
>http://www.qsl.net/na9d
>
>"A life lived in fear is a life half lived."
>
>
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