The paper *A Closer Look at Vertical Antennas With Elevated Ground Systems*,
by Rudy, N6LF goes into great detail on the subject. Referring to Figure
13, which compares Ga (Average Gain) for radial heights of 8' and 0.5' at
3.65 MHz, Rudy shows a gain difference of just 0.2 dB. This is for a 68'
radiator. Figure 16 shows the height-to-gain curve becoming asymptotic at a
radial height of 0.01 wavelength. This is 5' for us topbanders. Figure 17
is a similar graph for, I assume, the 40 meter band, and shows that at
radial height of half a foot things start to look good. Rudy strongly
advocates using many elevated radials to avoid pattern asymmetry caused by
unequal radial RF current.
https://rudys.typepad.com/files/elevated-ground-systems-article-final-version.pdf
At home I have a 40/80 meter vertical having two resonant radials per band
8' above ground. For portable 160 meter operation NH6V and I have used a
slant wire vertical with two resonant radials 10 to 20 ft. above ground.
Dave KH6AQ
On Thu, Jan 4, 2024 at 5:01 PM Radio KH6O <radio.kh6o@gmail.com> wrote:
> Attached is an interesting research paper by Clarence Beverage.
>
> --
> 73,
> Jeff KH6O
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