[TowerTalk] Re: tt
Eric Gustafson
n7cl@mmsi.com
Thu, 24 Feb 2000 16:41:54 -0700
Ray,
AMEN!!! and AMEN!!! again.
I think CFA must stand for Cold Fusion Antenna.
It is too bad that there are enough people intimidated by the
idea of evaluating Maxwell's equations that this kind of junk can
be successfully propagated.
The proponents of the CFA's reverse application of Maxwell's
equations put forward to explain why the CFA antenna is exempt
from the laws of physics is a bit like saying that since passing
a wire through a magnetic field creates a current (charge in
motion), then passing a moving charge through a magnetic field
must create a wire. If we could do that and have the process
generate a _GOLD_ wire, for example, we'd _really_ be in
business! It would beat the goal of the Alchemists all to heck.
(Actually, it is a darned good thing that this doesn't happen.
We couldn't watch Rocky and Bullwinkle reruns because the CRT in
our TV would quickly fill up with wire and short itself out.)
Maxwell's equations describe the _effects_ of what happens when
the _cause_ of a radiation field is present. The CFA proponents
are saying that they can create the _cause_ at high efficiency in
a small space by simulating the _effects_ using separate creation
of the requisite E and H fields in the proper relationship! The
fallacy in this argument is that it is not physically possible to
create either of the requisite fields (E or H) absent creation of
the other (H or E) in the same process. Since the structures for
this field creation (and the conductors leading to them) are all
closely spaced, these fields are all closely coupled to one
another, and the entire system is thus inextricably tied back to
"normal" physics. So the normal expectations of size versus
bandwidth versus efficiency must hold.
Here is another challenge for those with a mathematical bent to
work on in the time between now and when someone takes Chip's
money. - Starting from first principles, calculate the rate and
direction of Maxwell's spinning in his grave over the misuse of
his beautiful and insightful equations for such a purpose.
73, Eric N7CL
>Date: Sun, 20 Feb 2000 15:42:10 -0500
>From: Ray LaRue <w4byg@qsl.net>
>
>Be very careful with the wholesale acceptance and propagation of
>what is being written in the some foreign and ham literature, by
>some rather unorthodox people, about the CFA antenna and some of
>it's variations.
>
>The claims of it's proponents for: very wide bandwidth,
>substantial "gain", well above that of conventional antennas,
>all with very small size, are not well founded.
>
>Numerous people have tried to duplicate the results with no
>objective evidence of anything close to the claims of the
>originators. The main reason given where the feed systems
>weren't accurately built, etc. This has caused some to correct
>the supposed "errors" with several "revised" feed approaches.
>No confirmable success has been proven yet.
>
>The CFA within the US broadcast industry, has been characterized
>by many, as "voodoo" science. None of the claims by the
>inventors have been duplicable by responsible broadcast antenna
>engineers in this country.
>
>No antenna synthesis program such as NEC* or the like, confirms
>anything close to the claims of the inventors. In fact quite to
>the contrary. Most responsible attempts to simulate the results
>have shown performance 10 db or worse, below typical ground
>plane figures and severely restricted bandwidth. Claims that
>current CAE methods are at fault are not supportable.
>
>For something to be "scientific" it has to be observable and
>reproduceable with good methodology.
>
>The CFA is yet to show it can stand this sort of testing. So
>far it appears to be a myth or at least an erroneous series of
>conclusions by it's proponents.
>
>On July, 1999, Dr. Grant Bingeman, in comments to
>antennas@qth.net, made the statement: "As a member of the
>audience, (attending the 1999 NAB engineering forum, on the
>CFA), my conclusion is that apparently there are no concrete
>supporting numbers for the CFA claims."
>
>Recent attempts by myself, to obtain an HF prototype for some
>serious testing, have been unsucessful, so far. The design
>wasn't finished yet was the reason given.
>
>If you are really interested in the subject, drop Roy Lewellan
>or Tom W8JI, a line and see their comments. They've been into
>antenna design a long time. Their comments are worth serious
>consideration.
>
>Please also note the interesting challenge made on the NEC list
>by Chip N1IR and copied below: (I haven't heard of any takers
>yet).
>
>73,
>Ray LaRue, W4BYG
>Chief Engineer
>Consolidated Media Systems, Inc.
>Tampa, Fl
>
>Chip N1IR wrote:
>
>"For many months now we have heard on Antennex that CFA's are
>remarkably efficient antennas. This is despite presentations
>from Jefferies(also given here on Antennex), Belrose, and others
>that the 'new physics' explanation for the CFA's alleged
>performance is incorrect; that model and measurements of the CFA
>show very poor efficiency; and that a high efficiency (very
>electrically small) antenna cannot be broad band.
>
>I thus pose the following challenge: I will pay $10,000 to the
>first person or group who can demonstrate--using one or more of
>standard metrological methods--that the efficiency of a CFA less
>than 2% of a wavelength in size is in excess of 90%. Such an
>alleged radiator must also possess the broad band
>characteristics also ascribed to the CFA.
>
>This is a serious challenge, with absolutely no malice, spite,
>or 'agenda', other than to reveal: 1) the claims for CFA
>performance are not accurate and thus; 2) the requirement for
>'new physics' to explain such alleged performance is not needed.
>
>Only an accurate, scientific, and repeatable demonstration of
>the alleged high efficiency of the CFA will allow one to
>consider exotic new explanations. This challenge is a clear
>incentive to show that for those who believe it can be shown."
>
>73 Chip N1IR
>
>K7GCO@aol.com wrote:
>>
>> In a message dated 20.02.00 02:29:56 Pacific Standard Time,
>> tleaf@hotmail.com writes:
>>
>> << Hi again Ken,
>>
>> I already forget what the CFA antenna is. What is AntenneX
>> and how do I see it?
>> >>
>>
>> It's a very small antenna designed for the BC Band--using
>> different theory which is very sound.. Stations in Europe are
>> taking down their 1/4 wave verticals and installing the
>> CFA.. There are really 2 different types. One can go in ones
>> attic. They are in the "AntenneX" Web Site. It's a Web Site
>> Antenna Mag. Bring it up and subscribe. There are 5 articles
>> on the CFA. There is great stuff in there. They announced
>> the CFA a year ago. It hasn't been in QST They may not have
>> anyone that can cover it. k7gco
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