Gene Fuller wrote:
If you know anything about physics, you must know that energy is at the
core of almost all physical analysis.

I couldn't agree more, but that's exactly the topic from which you tried
to divert attention in your posting. Here's what you said:

"I guess I still need to seek out some "real-world physicists" to
figure out that energy is indeed something to "worry about". I
never would have imagined such a thing!"

If you don't worry about energy, you have nothing to add to the discussion.
If you do worry about energy, please read my "WorldRadio" article which
tells you more than you (and others) ever wanted to know about energy in an
RF transmission line.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil,

Sorry, I should have written,

"I guess I still need to seek out some "real-world physicists" to
figure out that energy is indeed something to "worry about". I
never would have imagined such a thing!" 8-) 8-) 8-)
8-) 8-) 8-) 8-) 8-) 8-) 8-) 8-) 8-)
8-) 8-) 8-) 8-) 8-) 8-)


I thought my intention was obvious, but it seems I failed to communicate.

73,
Gene
W4SZ



Cecil Moore wrote:
Gene Fuller wrote:

If you know anything about physics, you must know that energy is at
the core of almost all physical analysis.


I couldn't agree more, but that's exactly the topic from which you tried
to divert attention in your posting. Here's what you said:

"I guess I still need to seek out some "real-world physicists" to
figure out that energy is indeed something to "worry about". I
never would have imagined such a thing!"

If you don't worry about energy, you have nothing to add to the discussion.
If you do worry about energy, please read my "WorldRadio" article which
tells you more than you (and others) ever wanted to know about energy in an
RF transmission line.

Roy Lewallen, W7EL wrote:
"A short while ago, I explained why your Faraday cage doesn`t separate
the E and H fields as you claim."
n
I am misunderstood. I never used the tem Faraday cage. I understand the
Faraday cage to be a completely shielded enclosure which could be a
metal automobiole body, a steel rebar reinforced concrete structure or a
screened room. These all tend to completely block both the E-field and
the H-field components of an electromagnetic wave.

I gave an example of the metal rakes (Faraday screens) used at the
medium wave broadcast plants where I worked. The function of the Faraday
screen was primarily to eliminate capacitive cooupling, and thus the
E-field between the transmission line and the antenna. This reduces
harmonic radiation. It adds expense and complexity but is worth the
price for lightning suppression if for nothing else.

Most Faraday screens are used at powerline
frequencies to eliminate capaacitive coupling between primary and
secondary of a power transformer.

I checked the internet for a recent posting and found an article by
who wrote: "Beware, this cannot be an
auto-transformer. It must be a transformer with two completely isolated
windings, and with a Faraday Screen wound between the two."

Why would one pay a lot of extra money for a transformer which
eliminated capacitive coupling if it didn`t work, especially in Havana,
Cuba?

Best regards, Richard Harrison, KB5WZI

Gene, W4SZ wrote:
"How do you know that they also negate the fundamental properties of
time-varing electric and magnetic fields as expressed by Maxwell`s
equations?"

I did not make that claim.

Pits from the lightning strikes are evidence that the voltage gradient
is high between the coil and the Faraday screen. The second coil is
clean, not pitted.

I explained the operation of a Faraday screen earlier but was
misunderstood so I`ll quote a professional writer and consulting
engineer, B. Whitfield Griffith, Jr. who writes on page 246 of
"Radio-Electronic Transmission Fundamentals":

"It is often desirable and practical to allow one type of coupling
between circuits and eliminate the other. Figure 28-1, for instance,
shows two coils which are coupled but have a special type of shielding
between them that causes the coupling to be purely inductive and not
capacitive, This shield consists of an array of parallel wires which are
grounded at one end only. The lines of electric force from the coils
terminate on these grounded wires, so that there are no electric lines
of force passing from one coil to the other and hence no capacitive
coupling. On the other hand, since the wires do not form closed loops,
there is no circulating current in the shield and therefore nothing to
stop the penetration of the shield by the magnetic field. This type of
shield has long been known as a Faraday screen. It is important that the
capacitive coupling be eliminated in many cases, since it has the
characteristics of a high-pass filter, tending to accentuate the
harmonic content of the transmitted signal."

I never tried it, but I`d bet that someone has measured the radiated
harmonics both with and without the Faraday screens inplace. That would
prove effectiveness.

Short-circuiting the open ends of the Faraday screen wires would kill
transfer of the signal between primary and secondary of the transformer,
and the transmitter would likely complain.

Best regards, Richard Harrison, KB5WZI

*Sigh*

Richard Harrison wrote:
Roy Lewallen, W7EL wrote: "A short while ago, I explained why your
Faraday cage doesn`t separate the E and H fields as you claim." n I
am misunderstood. I never used the tem Faraday cage. I understand the
Faraday cage to be a completely shielded enclosure which could be a
metal automobiole body, a steel rebar reinforced concrete structure
or a screened room. These all tend to completely block both the
E-field and the H-field components of an electromagnetic wave.

Sorry, I meant "Faraday screen", which is the term you used, and I used
in my posting explaining its operation.

If you block either the E or H field, you also block the other. You
can't independently block one or the other.

. . .

Why would one pay a lot of extra money for a transformer which
eliminated capacitive coupling if it didn`t work, especially in
Havana, Cuba?

Because in order to "work" it doesn't need to "eliminate capacitive
coupling". All it needs to do is locally reduce the E/H field ratio,
which is what it does.

Roy Lewallen, W7EL

Gene Fuller wrote:
I thought my intention was obvious, but it seems I failed to communicate.

Others on this newsgroup have admonished me for worrying about
energy and refused to discuss the subject. I thought you were
doing the same. Sorry. But do you actually have any references
that contradict "Optics", by Hecht?

In Dr. Best's article, he superposes V1 with V2 such that constructive
interference energy is needed to complete the superposition. On this
newsgroup, I asked Dr. Best where that necessary constructive interference
energy comes from and he didn't know. That's when I went searching for
references and found them in the field of optics.

Constructive interference energy can be supplied by local sources
as occurs in W7EL's "Food for Thought #1" with its DC example. Or
constructive interference energy can be supplied at a point away
from the source(s) by destructive interference, e.g. wave cancellation
at the non-reflection surface of a layer of thin-film on glass or
at a match point in a transmission line.
--
73, Cecil http://www.qsl.net/w5dxp

After reading this thread it seems there is significant confusion between E and
H fields created locally from electric current and the E and H aspects of a
passing RF photon stream. It is easy to see how this can occur. That said the
tools for working with them are entirely different.

E and H fields from capacitors, inductors, and transformers are predominantly
local effects. Photons are not involved, they are created by electric current
and are explained by Maxwell equations. They can be created separately, that is
a capacitor is pretty much a pure E field and an inductor an H field, albeit
none of these are perfect. Photons are not involved in the operation of a

On the other hand EM waves and photons which are RF waves and visible light and
beyond are entirely different. Although they are referred to as
electro-magnetic, they are in fact massless particles with a well defined energy
that is a function of frequency. These particles, traveling at the speed of
light, create what is referred to as RF including RF fields. The E and M
components cannot be separated. Antennas are devices which convert RF currents
into photons for transmission and to convert photons into RF currents on
reception, all this at the frequencies we are mostly interested in.

These are two very different physical constructs. Now at RF frequencies -
Faraday shields are local electrical devices, they have nothing to do with
photons and antennas. (Although they may be effective at blocking their
passage.) Electric currents in equipment create both E and H fields. These
fields are not associated with photons and can be separated. Faraday shields are
a way to block the E portions of those local fields while allowing the passage
of the H.

Dan

Roy Lewallen wrote:
*Sigh*

Richard Harrison wrote:

Roy Lewallen, W7EL wrote: "A short while ago, I explained why your
Faraday cage doesn`t separate the E and H fields as you claim." n I
am misunderstood. I never used the tem Faraday cage. I understand the
Faraday cage to be a completely shielded enclosure which could be a
metal automobiole body, a steel rebar reinforced concrete structure
or a screened room. These all tend to completely block both the
E-field and the H-field components of an electromagnetic wave.


Sorry, I meant "Faraday screen", which is the term you used, and I used
in my posting explaining its operation.

If you block either the E or H field, you also block the other. You
can't independently block one or the other.

. . .


Why would one pay a lot of extra money for a transformer which
eliminated capacitive coupling if it didn`t work, especially in
Havana, Cuba?


Because in order to "work" it doesn't need to "eliminate capacitive
coupling". All it needs to do is locally reduce the E/H field ratio,
which is what it does.

Roy Lewallen, W7EL

Richard Clark, KB7QHC wrote:
"From your copy of Bailey, review the text, and reconcile his remarks."

Richard Clarks advice is good. Arnold B. Bailey in "TV and Other
Receiving Antennas" does a more extensive job of explaining how antennas
work than most other authors. Wish everybody interested in antennas
could read Bailey.His catalog of antenna types is convenient too.

Best regards, Richard Harrison, KB5WZI

Dan Sawyeror wrote:
"They can be created separately, that is a capacitor is pretty much a
pure E field and an inductor an H field."

Agreed.

Whenever a current grows or shrinks (with acceleration) it produces both
an E-field and an H-field. I didn`t clam a permanent divorce, only an
instantaneous separation.

Best regards, Richard Harrison, KB5WZI

"dansawyeror" wrote -
After reading this thread it seems there is significant confusion
between E and
H fields created locally from electric current and the E and H
aspects of a
passing RF photon stream.
========================================

When the geometric dimensions of the structures are short compared
with a wavelength, the amps and volts are associated with the NEAR
FIELD and Ohm's Law applies.

The radiation field is so weak in comparison it can be forgotten
about. KISS.

Why does everybody HAVE to unnecessarily complicate matters in order
to understand what really goes on?

What have photons to do with winning a contest? ;o)
----
Reg.