A certain Topband poster apparently originated and supports driving a 160m
vertical monopole against an elevated, folded counterpoise ("FCP") in
situations where dense and uniform buried radials are deemed
impractical/undesirable/unnecessary.
Recently this same proponent posted this exchange in a Topband thread:
(B) What is the "ideal" number of elevated radials that one should
use...?
Somewhere between 16 and 32 it gets hard to see any further change. For
commonly achievable 160m heights of radials, the degree of change depends
some on height and more on quality of ground.
Later posts on Topband with links to real-world systems and NEC4
calculations showed that driving a monopole against just four 1/4-wave,
elevated radials produces close to 100% radiation efficiency, regardless of
earth conductivity in a horizontal radius of 1/2-wavelength from the base of
the monopole.
Here is a clip of one web post I saw from this proponent describing the
physical layout of an FCP for 160m:
Counting FCP segments 1 through 5. 33 feet per segment. Directions used
are for illustration only.
1: center to 33 feet east
2: 33 feet east back to center
3: center to 33 feet west
4: 33 feet west back to center
5: center to 33 feet east and end insulator.
The description seems to define a single conductor zig-zagging back and
forth roughly along the same linear axis.
So the question becomes, does a single elevated "FCP" (folded) radial
configured in a zig-zag physical form enable the same antenna system
radiation efficiency as if such a conductor/conductors are linear, and which
according to this proponent need at least 16 such linear conductors for
system performance approaching 100% radiation efficiency?
Also, are there any scientifically valid proofs/measurements that the
radiated fields of a real-world monopole system when using an FCP of this
description will equal, or even approach the efficiency of that monopole
when driven against just 4 x 1/4-wave horizontal radials installed at the
same elevation, at physical intervals of 90 degrees?
Clarifications/comments gratefully sought.
RF
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Topband Reflector
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