[TowerTalk] Radials

Dudley Chapman chief at thechief.com
Tue Nov 22 12:25:21 EST 2005

>A quote from Polyphaser: "A good lightning ground is also a good RF ground.
>But a good RF ground is not necessarily a good lightning ground."
>The RF ground and lightning ground need not be treated separately.
>Heavy radials are not necessary if there are more than a few. The lightning
>energy will be divided among all so no single radial will carry high
>Insulated wire radials will dissipate the higher frequencies involved in
>lightning but bare wires will be required for the low / DC component of
>lightning. The insulated wire will arc to ground as voltage rises but bare
>wire will help keep that arc point lower.
>Arcing to ground with bare wire still happens at times in some soil types.
>Some broadcast stations employ ground rods along the radial lengths when
>difficult soil conditions are present for lightning dissipation.
>A properly installed radial system can be both an excellent RF ground and
>lightning ground as a large portion of lightning energy is in the RF
>As a mater of interest, you do not have a good lightning ground unless it
>a good RF ground in addition to a good DC ground.
>Gary  K4FMX

   I am now officially confused.  Suppose I built a vertical and ran 40 0.2
wavelength rf radials of insulated #14 wire along the top of the ground.
Suppose I had a single ground rod near to and connected to the radials near
the vertical.  How would you augment this installation to provide good
lightning protection?  Wouldn't it still require a handful of heavy gauge
radials with ground rods along their length?  

Dudley - WA1X

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