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Re: [TowerTalk] 1/4 wave vertical with counterpoise

To: towertalk@contesting.com
Subject: Re: [TowerTalk] 1/4 wave vertical with counterpoise
From: Jim Lux <jim@luxfamily.com>
Date: Sat, 17 Jan 2026 18:28:36 -0800
List-post: <mailto:towertalk@contesting.com>
Well, this is sort of what folks are trying to do with various metrics that attempt to weight things.  It's tricky, because we (very inclusive we for all users of antennas) like to have some sort of testable/calculatable requirement that's boiled down to a single number, like EIRP, or peak angle, or sidelobe levels.

It's not unique to antenna patterns (look at SAR folks with integrated sidelobe vs peak sidelobe levels, for instance) - IM3 is a popular, and straightforward to measure, number - but not necessarily directly relatable to performance with complex waveforms or with amplifiers with transfer functions that aren't nicely represented by a low order polynomial function.

(and what HFTA has with it's plots of arrival angle statistics)


On 1/17/26 3:17 PM, Jim Brown wrote:
On 1/17/2026 2:30 PM, David Gilbert wrote:
For one thing, there were so many plots that if I put them all together the result would have been gibberish.

Of course. But doing so selectively can be quite valuable.

Secondly, the shapes of the elevation plots and the various signal strengths were so similar in almost all cases that ti wasn't necessary

The polar plot of field strength vs elevation obscures significant differences at low vertical angles. Yes, on the polar plot they all look the same, and those low vertical angles are important. THAT'S why I "keep harping on it."  :)

 Besides, the video was already well over 20 minutes and getting too long.

The length of the video is fine. My suggestion could have improved it, and perhaps aided your analysis by improving your view of the data.

73, Jim K9YC

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