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Re: LF: RE: CFA

To: [email protected]
Subject: Re: LF: RE: CFA
From: [email protected]
Date: Sat, 13 Nov 1999 21:54:35 EST
Reply-to: [email protected]
Sender: <[email protected]>
In a message dated 11/13/99 5:19:38 PM Eastern Standard Time, [email protected] writes:
<< The way I perceive the situation, some people are becoming upset because a
new approach (unfortunately labeled "revolutionary") does not match the
theories we have all learned. >>
 I have a somewhat different perspective, I guess. It appears to me that
supporters of supposedly revolutionary approaches become upset when the rest
of us don't jump on the bandwagon without proof... which, in this case, is
still not at hand, nor particularly imminent. They fall back on the argument
that we're blinded by "conventional theory."
 I put that in quotes because I'm not sure what "conventional theory"
they mean; perhaps the generalizations and rules of thumb for specific
antenna types that make it into amateur handbooks or other popular
literature. In this sense, "conventional theory" falls short of describing a
good many existing antennas, but it's only because we're accustomed to
looking at such a limited subset of that theory.
 When it comes to electromagnetics, the field --no pun intended-- that
properly encompasses all antennas, the available body of theory is far more
than a collection of hypotheses. It's founded in Maxwell's work, which the
CFA inventors themselves invoke freely (the question now being, how loosely
have they done).
 Conventional theory has been tested since the days of Prof. Hertz and
not found wanting. It is not just an explanation for why everyday antenna
systems work, but a powerful tool for predicting some very unconventional
ones. This is the test that makes theory in the formal sense something
vastly more than an hypothesis.
 The maths of electromagnetics are more than most of us comprehend,
beyond the mere mechanical level of plugging numbers into equations.
However, there are those who do appreciate the subtleties behind the numbers,
and have manipulated them in very creative ways to produce antennae that
don't look anything like monopoles or dipoles: slot antennas, dielectric
rods, horns... the list goes on and on. As different as they all are, they
are not only understood in terms of conventional theory, but are a direct
result of its accurate application.
 Whether the CFA will belong to this family or not remains to be seen. I
concur with Andre' that there should be good opportunities to measure the
results from the IoM station.
 I don't believe I'll be satisfied by it just working, though. Of course
it will work. As Peter mentioned, experimenters already know how to radiate
RF from woefully miniscule aerials. In addition, I have heard CFAs on the
air. Barely. My skepticism arises not from fear that old ideas will have to
be revised, but from the consistent reports of users that their CFAs are
"almost" as strong as their regular antenna systems. This does not readily
square with glowing claims that CFAs are frequency-independent and inherently
more efficient than resonant antennas.
 The question to be answered is really twofold: Does the CFA truly work
well enough to represent a breakthrough? Will any real engineering data be
gathered INSIDE the antenna (current distribution and phase among the
elements)? Without satisfactory answers to both parts, claims of any new
principle at work will remain completely baseless.
73,
John  KD4IDY


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