[TowerTalk] Half wave verticals/ground system

[alsopb]

Those interested in half wave verticals should read ON4UN's low band
DX handbook.
In the section titled "The Radial System for a Half-Wave Vertical" he
states:

"Here comes another surprise.  A terrible misconception about
voltage-fed verticals is that they do not require a good ground nor an
extensive radial system"

The section goes on to show that a half wave vertical requires 0.6
wavelength long radials to perform as well as a quarter wave vertical
with quarter-wave radials.

Note: these are end fed verticals.

I read this section many times and concluded there is no incentive to
ever go to a 1/2 wave vertical on any HF band.  If you want to extend
the length of your vertical 5/8 wave is a winner.  Consult ON4UN's
handbook.

I don't have the expertise to discuss this.  Those who wish to debate
this do so leaving me out.

73 de Brian/K3KO


Thor Hallen wrote:
> 
> The 1/2 wave vertical dipole is a conceptually different antenna from the
> classical 1/4 wave vertical and does not depend any ground system at all.
> It can be thought of as a normal horizontal dipole standing on end. The
> half wave verticals that are end fed like the Cushcraft series use a small
> counterpoise to reduce the drive point impedance for matching 50 ohms. The
> center fed 1/2 wave verticals do not use a counterpoise as they provide a
> good match to 50 ohms as is. The counterpoise is not a ground and the
> antenna will not function if you attempt to replace the counterpoise with a
> ground system. The end fed version can be thought of as a horizontal Zep
> standing on end with a capacitive hat.
> 
> The EZNEC antenna simulation program has a very accurate model for ground
> and can be specified to be anything from very poor like encountered in
> inner city to excellent as encountered over sea water. The simulation
> accuracy has be verified by many experiments comparing simulation to actual
> measurements of field strength and VSWR.
> 
> 73,
> Thor Hallen K5AGE
> 
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