[Antennas] Vertical

Wed Nov 30 16:47:48 EST 2005

Don, that was the best summary of verticals and dipoles I have seen in a
long time. It certainly reflects years of experience and knowledge on the
subject.
I will add that between the 1/2 WL maximum efficiency height of a horizontal
dipole, and the minimum 1/4 WL height of same, there is a lot of room for
excellent results. At just above 1/4 WL elevation, a 55 meter center-fed
horizontal dipole for instance becomes a superb performer. The 45 meter
dipole (fan) under it is of course very close to (its) 1/2 WL elevation, and
has only slightly better range. Both are tested on the DXTuners Caracas,
Venezuela receiver during daylight hours running bareback.
The difference between 'just above' 1/4 WL elevation and the ideal 1/2 WL
elevation is rather minimal in percentage of improvement, but exponentially
more difficult to erect and maintain. Mr. Cebik, or another I cannot recall,
had a graph showing the efficiency gain as the dipole elevation increased
from 1/4 WL to 1/2 WL. What it expressed to me, was that anyone who could
achieve 1/4 WL elevation on a long horizontal dipole, will probably be very
happy with it.
73,
Jack, in wet soil in
Virginia Beach
>-----Original Message-----
>From: Hendrid at aol.com
>>Hi Sean,
>>Not sure how this adding a reply works, but Cebik has done a lot
>of analysis
>and antenna testing and is a well accepted authority on hf dipoles and
>verticals. His conclusion is that gain wise, a well made dipole
>in the clear and
>up about 1/2 wavelength is about as good as you can do for a wire
>antenna or
>a vertical. This includes versus low take off angle which the vertical
>favors.
>>For those of us that do not have a clear area and the capability to get a
>dipole up 1/2 wavelength, and for dx or long range communication
>(farther than
>1000 miles or so), the vertical or some similar antenna such as a
>half square
>would probably be favored. I have built and used a number of low dipoles
>and some verticals (not very successful on verticals) over the years and
>studied what others have said and done. An elevated vertical
>(base elevated) seems
>to get out significantly better than a ground mounted one if 4 or
>more also
>elevated radials are used.
>>For ground mounted verticals, 50 or more radials seems optimum
>with 130 or
>more near perfection but 4 or so does work. Also, what many vertical
>theorists and builders and users seem to neglect is the "ground plane"
>characteristics of the soil at 2 to 4 wavelengths from the base of
>the ground mounted
>vertical in addition to the radials at the base of the vertical.
>That is the
>reason that verticals are not normally recommended in the desert
>or where the
>soil is dry. Verticals next to an ocean shore or a body of water
>or moist soil
>normally work great.
>>Hope this helps, Don NT7N Grants Pass, Oregon
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