Topband: Current Distribution on Buried Radials Used With Vertical Monopoles

[Guy Olinger K2AV]

"Laying on the ground"  could mean anything from laying directly on dirt to
top of the grass 5 cm above the dirt. That is a wide swing in VF.  73, Guy
K2AV

On Tuesday, March 10, 2015, Eduardo Araujo <er_araujo at yahoo.com> wrote:

>
> "A specific description from you about the ground used for radials would
> be very interesting.
>
> 73, Guy K2AV"
>
> Guy and all,
>                    Unfortunately the only data about terrain is almost
> flat farm land conformed by humus and neutral PH.
>
> Before having the tower and just for fun, I decided to play with Rudy N6LF
> measurements, against an inverted L, and to my surprise, I got extremely
> similar results about shortening radials and measuring the current of each
> of them at the antenna Base. Also, I did FS measurements at ground level at
> about 300 mts which acompanied the increase in current at the base of the
> antenna.
>
> Also I repeated the test of having 4 x 1/4 wave radials lying on the
> ground, measuring its current and FS. Then, raising them up in 3 step up to
> 85 cm from the ground and the change in FS measurement related directly
> with Rudy measurements....a huge change.
>
> Finally a comment about "lying on the ground" that I shared with Rudy, if
> you have 20 or less radials (I didn´t do it with more) and shorten them for
> maximun current at the base, which in my case was accompanied by an
> increase in FS, they are quite sensitive to the distance from the ground
> specially the last 1 or 2 mts. What I found was that if the grass move your
> radial up let say 5 cm in the last couple of meters, and the next one is
> just lying on the ground, even though equal physical length will have
> different currents ergo different length to both have the peak at the
> antenna base.
>
> As the number of radials increase, the radial length increased and that
> sensitivity gets smaller.
>
> Good dx to all.... Eddie, LU2DKT
>
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