Topband: soldering radials

[Charles Moizeau]

Jorge,

The short answer is the 120 18-gauge radials will be much
more effective than the 40 radials.

 

Consider two absurd examples: 1) all 120 radials are
connected in parallel and laid in a single shallow trench; 2) all 120 radials
are connected in series and laid in a single shallow trench that is very
long.  Each configuration will provide a
completely worthless ground system.

   

The effectiveness of a radial system is not directly
proportional to the total amount of copper in the ground.  Rather, a radial system’s effectiveness
results from how a certain amount of copper wire is divided to provide a
certain number of radials, each of a certain length and arranged over a certain
area in proximity to the radiator.

 

The quantification of number, length and area has been well
studied, and some pretty well established guidelines that have been
published.  Almost all of this material
relates to a vertical antenna where the point of maximum current is at the
radiator’s base, the case with a ¼ wavelength-high radiator.  

 

What still requires more investigation is the optimum
radial field for a vertical antenna where the point of maximum current has been
raised above ground level, the case with a radiator whose length is greater
than ¼ wavelength, whether physically so or electrically so by virtue of
inductive or capacitive (top) loading. 
In such instances, the dense concentration of radials at the radiator’s
base is of less value than when it is adjacent to radiator with maximum current
at its base.  Therefore, for a given
amount of copper wire, other configurations, e.g., “crow-footed” radials, may provide
a better radial system.  

73,

Charles, W2SH   

> From: cx6vm.jorge at gmail.com
> To: topband at contesting.com
> Date: Thu, 18 Aug 2011 10:13:00 -0300
> Subject: Re: Topband: soldering radials
> 
> Thanks all for the answers...
> 
> I am working on collection the materials for the project, so all feedback is
> very important for me, thanks.
> 
> Just was thinking, is the same or better to have 120 radials of AWG18 than
> 40 radials of AWG8? What´s the idea? This is the same amount of copper, but
> the distribution over the ground is different.
> 
> 73,
> Jorge
> CX6VM/CW5W
>