Elevated Radials
I hear this all the time that a high dipole will outperform a vertical over
poor soil - but many people put verticals up to get some sort
of DX capable antenna up because they don't have a way to get a high dipole
up, so they try to get their vertical to work as well as they can.
N4IJ
On Sat, Jan 22, 2022 at 12:01 PM <towertalk-request@contesting.com> wrote:
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> Today's Topics:
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> 1. Elevated Radials (Wilson Lamb)
> 2. Vertical and radials (John Langdon)
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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 21 Jan 2022 21:14:54 -0500 (EST)
> From: Wilson Lamb <infomet@embarqmail.com>
> To: towertalk <towertalk@contesting.com>
> Subject: [TowerTalk] Elevated Radials
> Message-ID:
> <816180107.126259977.1642817694909.JavaMail.zimbra@embarqmail.com>
> Content-Type: text/plain; charset=utf-8
>
>
> My friend Steve, W3AHL is a good modeler.? He took my basic wish for a
> good 160m vertical and designed elevated radials to fit.
> Much as described in one of the recent postings, Steve recommended four
> 75' radials seven feet above ground, tuned with a coil in the common
> connection.
> Each was tuned against the 60 ft vertical element.? The T top load is 132
> ft long.
> The vertical element is ladder line, not shorted at the top, so the
> antenna makes a great 80m dipole, when matched at the bottom with an L
> network.
> This was all done in anticipation of Bouvet Island getting on, but it's
> been fun anyway.? I work EU with 100W and JA and ZL with a few hundred and
> am up to 70 countries, with just casual effort.
> I'd do better if I put up some Beverages, since I have email reports from
> people who have heard my CQ but been unable to reach me.?
> With 800W, the far ends of the radials are hot enough to char the bark, if
> they touch a tree.? Electric fence insulators fixed that.
> This is by far the best antenna I've ever built and has produced a lot of
> fun.? Thanks Steve!
> Wilson
> W4BOH
> ?
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 22 Jan 2022 05:58:45 -0600
> From: "John Langdon" <jlangdon1@austin.rr.com>
> To: <towertalk@contesting.com>
> Subject: [TowerTalk] Vertical and radials
> Message-ID: <016601d80f87$690c6050$3b2520f0$@austin.rr.com>
> Content-Type: text/plain; charset="us-ascii"
>
> The other thing that K5IU was clear about is that the ground under the
> antenna is the dominant factor in performance regardless of the radials you
> use.
>
>
>
> If you have really low conductivity soil under the antenna, even if you
> mount a vertical on a 1/4 wavelength radius copper disc, essentially an
> infinite number of buried radials, you are going to get poor performance.
> Elevated radials will be as good or better in that situation, and are less
> work, but a high dipole, over poor soil, will be equal or better.
>
>
>
> If you have really high conductivity soil, a modest number of buried
> radials
> or a set of 4 1/8 wavelength elevated radials tuned with an inductor will
> probably give you good performance.
>
>
>
> If you are over salt water, a single resonant radial will work very well.
>
>
>
> BTW the ground conductivity maps most of us have access to, like
>
> https://commons.wikimedia.org/wiki/File:United_States_Effective_Ground_Condu
> ctivity_Map.png
> <https://commons.wikimedia.org/wiki/File:United_States_Effective_Ground_Conductivity_Map.png>
> , are from data averaged over a large area and any given
> location within an area on the map may vary widely from the average. The
> perfect QTH is a hill of salt water, sloping gently in all directions.
>
>
>
> 73 John N5CQ
>
>
>
>
>
>
>
>
>
>
>
> ------------------------------
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> ------------------------------
>
> End of TowerTalk Digest, Vol 229, Issue 18
> ******************************************
>
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