Topband: "Missing" Buried Radials for a Monopole

Tom W8JI w8ji at
Fri Aug 24 12:15:10 EDT 2012

> Do you think that radials --either elevated or laying on the ground--
> radiate? Or does all of the radiation come from the vertical monopole 
> under
> the radial system?

There is no question radials radiate, and it is impossible to stop them from 
radiating or coupling to things around them, at least in the near field.

If they didn't radiate or couple, they couldn't do anything. :-)

> There is a recent thread about this on the Antenna-discussion
> forum, which I originated. I tend to believe that while there is a local
> field around the radials, it does not go far. The far-field radiation only
> comes from the vertical portion.

There are three "fields" at work. Electromagnetic, which is a weak force but 
unless cancelled goes on through space forever. Electric and magnetic 
induction fields, which are rapidly decaying fields involved in local energy 
storage and distribution.

The question is really all about proportions. Nothing cancels the EM field 
from a single radial except earth reflection. Two radials can pretty much 
cancel in the farfield, but not perfectly. Model a freespace groundplane 
with two perfectly balanced radials. You will see the pattern distortion 
caused by radial radiation.

Near earth, there is an "image" that helps cancel radiation, but it isn't 
perfect. If it was perfect our Beverages would not work as Beverages. If the 
image was missing our ewe and flag antennas would not work nearly as well.

We have to watch making things black and white.

73 Tom 

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