Topband: Elevated Radials

[Richard Fry]

Guy Olinger posted:
>...The very same NEC 4.2 with raised quarter wave radials over routine real 
>life ground made of dirt will show field intensities in the ground. (etc 
>etc)
_______________

Sorry, but this is a misunderstanding/misuse of NEC for this situation.

The r-f currents flowing in the earth under and near elevated, horizontal 
radials are NOT the source for the r-f currents flowing on those radials, 
themselves.  Those radial wire currents are supplied by the currents flowing 
on the inside surface of the outer conductor of a coaxial transmission line 
used to drive the monopole -- which is connected to the common point of 
those elevated radial wires.

Elevated radials behave much differently than buried radials.  In effect, 
driving a vertical monopole against an even number of geometrically- 
symmetric pairs of at least two elevated, horizontal wires used as a 
counterpoise converts a base fed (unbalanced) monopole radiator into a 
balanced radiator -- which neither needs, nor can use a structural 
connection to the earth for most efficient system performance.

For proof of this, please study the measurements of a real-world system 
using 4 x 1/4-wave elevated radials described in the link below, for/at 
WPCI, 1490 kHz in Greenville, SC, and the rest of that paper.

http://www.commtechrf.com/documents/nab1995.pdf

RF