Re: NEC-LIST: CFA talk

-------------Forwarded Message-----------------

From: Brian G Stewart, INTERNET:b.stewart_at_gcal.ac.uk
To: Grant Bingeman, DrBingo
        
CC: [unknown], INTERNET:jack_at_antennex.com
        Ted Hart, INTERNET:W5QJR_at_hom.com
        
Date: 2/15/99 3:10 AM

RE: Re: CFA talk

Dear Grant

Unfortunately I've been unable to open your file. Such is Mr Gates
problem! Would you still like a copy of the CFA paper over the
e-mail?

Grant thank you for the issue regarding a difficult question for the
NAB conference. However I'm a little confused by it.

You see we have always stated that the E -plates (which people refer
to as the shortened/fat dipole) produce the main component of E field,
not the disks. In addition the disks produce the main H field and not
the E field. These are then phased to be in in time phase for outward
Poynting vectors. Your question had this point the other way round.

The question you may now wish to ask relates to any H field produced
from time varying E from the E-plates and also any E from time varying
H from the D plates. Where are they? The answer is that most of the
energy associated with these "back" fields are in the radiated
waves. How do I know this? Well the E and H which produce the radiated
power are designed in the CFA to satisfy the equations D' = curl H and
B' = -curl E which are actually the "back" field equations. We now
have wave equations set up from Maxwell's equations and thus radiated
power. Again I am not suggesting anything which is inconsistent with
standard antenna and electromagnetic theory.

All the issues you have quite rightly raised can also be asked of
standard antenna and electromagnetic theory.

Grant I don't mind you posting my previous response on the NEC
list. However, please bear in mind the details to you were informal -
not written as the definitive all encompassing "truth". The only
problem I would envisage is that I won't have time to answer all the
questions raised!

Best wishes

Brian

Grant Bingeman wrote:

> Bryan, here is another tough question which is likely to come up at
> the NAB Show:
>
> The CFA can be put to rest by a simple exercise. Try this and see:
>
> The inventors claim that it "works" because the E field from the
> disc plates when crossed into the H field from the fat
> dipole/monopole, (which has a 90 phase shift forced by the phasing
> network) shows the required "in-phase relationship and quadrature
> space relationship" for an outward going poynting vector! (Sounds
> and looks good! Real in-phase power!)
>
> But they conveniently "forgot" to include the remaining E from the
> quadrature shifted dipole and the H from the discs! Those cute
> little devils just so happen to produce and INWARD GOING poynting
> vector, which adds up to NO real power over that from a small
> dipole! (SIGH!)
>
>
> How would you respond?
>
> Sincerely,
>
> Grant Bingeman
Received on Mon Feb 15 1999 - 19:31:24 EST