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[antennaware] Re: [TowerTalk] LPDA gain figures

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Subject: [antennaware] Re: [TowerTalk] LPDA gain figures
From: (Guy Olinger, K2AV)
Date: Thu, 07 Oct 1999 16:41:49 GMT
On Thu, 7 Oct 1999 06:23:26 -0500, you wrote:

>> If I'm going to bet, it would be on Maxwell's
>> Equations.
>And if the issue were just if Maxwell's occasions were correct, I'd be at
>the same table with you, 

This seems to be one of those degree of effect things.

Model ling of plain (no traps, no bends, no loading, no 4 inch element
separations, just aluminum tubing, etc) elements and their
combinations has really gotten to the stage where the onus lies upon
the anecdotal (kick butt, etc) to show where they fit it.

I freely admit this is clearly not so with many other kinds of
antennas, my personal irritation being with low-band linearly-loaded

In the case of LPDA's, the models really give one an OPTIMUM gain,
which, alas, one can only mess up to achieve less.

It's kind of like the space shuttle. It takes the most gifted pilot to
equal or better the computer doing the landing.

I have an inverted L (63' up, 70' out, with the horizontal part
broadside to 30 degrees, which I end-feed on 7 mHz. I have equaled a
quad (end of WPX score) with apex at 130'. I have gotten through a
pileup ahead of W3LPL. 

Does this refute or invalidate the models which show 5 db or better
gain on the part of the quad or LPL's excellent yagis? The models only
calculate the effects of laws of physics in the abstract, and their
hard comparisons force one to go elsewhere than "my kick-butt antenna"
to explain what happened in the paragraph above:

1) A Quad antenna with an effective height of 110' feet has a null and
a region of diminished gain in important mid-opening arrival angles --
more than enough diminishment to reduce it to the level of my inverted

2) In a cw pile up, a serendipitous choice of send offset makes my
signal loud and LPL's diminished by the DX's receiver passband. I got
lucky. Beyond that, the better operator has the advantage in any
pileup. At the end of a contest, a superb operator with 100 watts and
a dipole will trounce a lid with a yagi and a kw. Was that a "Kick
butt dipole"? Look at the contest scores and see how many HP scores
were exceeded by the top LP scores with a 12 dB handicap right off the
bat. What are we arguing about in LPDA vs. Yagi, 2 db, maybe maybe

I'm with Brian on this one.

73, y'all

--.  .-..
73, Guy

Guy Olinger, K2AV
Apex, NC, USA

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