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Old December 4th 09, 12:04 PM posted to rec.radio.amateur.antenna
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Default Faraday shields and radiation and misinterpretations

On Thu, 03 Dec 2009 14:13:57 -0800, Richard Clark
wrote:

On Thu, 03 Dec 2009 16:51:05 -0500, Registered User
wrote:

- good stuff from RC snipped -

Either way I've learned as current varies the fields it produces will
vary. If the fields vary they're not static. Too simplistic? What am I
missing?


Static comes in two flavors. One means "not moving." The other means
high potential (which can be "not moving" AND, ironically, "moving").
Such is the legacy of electrostatic potential covering DC to Gamma.

I was wondering about the latter as a possibility but couldn't find
the proper words. My interpretation is although the individual fields
may vary the total potential of the fields is constant. Is this
correct?

The difference between rods, number of rods, thickness of rods, and
mesh all speak to bandwidth. 2, 3, or 4 rods will not be remarkable.
16 rods will closely approximate a cone of sheet metal (as would a
grid of similar spacing). The same can be said of the
rod/rods/mesh/sheet in the upper section approximating a solid disk.

IIUC the current flows around the cone of a discone regardless of
solid, sheet or mesh construction. This appears to be contrary to the
quote above where current flows around each individual hole in the
mesh.


Well, language can be a barrier here when you say "around the cone."

I should have said the current flows around the cone parallel to its
base.

- more snippage -

I appreciate the clarifications and the links. It all helps to better
my knowledge and understanding of these topics. Thank you
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Old December 4th 09, 06:19 PM posted to rec.radio.amateur.antenna
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Default Faraday shields and radiation and misinterpretations

On Fri, 04 Dec 2009 07:04:28 -0500, Registered User
wrote:

Static comes in two flavors. One means "not moving." The other means
high potential (which can be "not moving" AND, ironically, "moving").
Such is the legacy of electrostatic potential covering DC to Gamma.

I was wondering about the latter as a possibility but couldn't find
the proper words. My interpretation is although the individual fields
may vary the total potential of the fields is constant. Is this
correct?


Electrostatic is properly applied to charge that is NOT moving, or
moving very slowly.

The same thing can be said of Magnetostatics as being derived from a
current that is constant, or altering very slowly.

The sense of either of these strict terms residing in the RF denotes
the poverty of idea that takes up residence here as invention. There
is plenty of examples to be found on the Web too. It is unfortunate,
like the camel's nose under the Arab's tent, that taking "very slowly"
and winding out the tach to 100GHz is the pollution of meaning.

What we are concerned here with is electromagnetics infrequently known
as electrodynamics and rarely as magnetodynamics. The sense behind
electromagnetics is inclusive of dynamics of which statics is a
special case.

Dynamics, of course, means time-varying. In EMF, or electromagnetics,
what varies is magnitude and/or polarity of the electric and magnetic
field. What you find "constant" about the fields (properly observed
as plural) is in their orthogonality (one field is building the other
as it decays in amplitude).

Well, language can be a barrier here when you say "around the cone."

I should have said the current flows around the cone parallel to its
base.


That doesn't happen.

73's
Richard Clark, KB7QHC
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Old December 4th 09, 06:42 PM posted to rec.radio.amateur.antenna
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Posts: 707
Default Faraday shields and radiation and misinterpretations


"Richard Clark" wrote
...
On Fri, 04 Dec 2009 07:04:28 -0500, Registered User
wrote:

Static comes in two flavors. One means "not moving." The other means
high potential (which can be "not moving" AND, ironically, "moving").
Such is the legacy of electrostatic potential covering DC to Gamma.

I was wondering about the latter as a possibility but couldn't find
the proper words. My interpretation is although the individual fields
may vary the total potential of the fields is constant. Is this
correct?


Electrostatic is properly applied to charge that is NOT moving, or
moving very slowly.

The same thing can be said of Magnetostatics as being derived from a
current that is constant, or altering very slowly.

The sense of either of these strict terms residing in the RF denotes
the poverty of idea that takes up residence here as invention. There
is plenty of examples to be found on the Web too. It is unfortunate,
like the camel's nose under the Arab's tent, that taking "very slowly"
and winding out the tach to 100GHz is the pollution of meaning.

What we are concerned here with is electromagnetics infrequently known
as electrodynamics and rarely as magnetodynamics. The sense behind
electromagnetics is inclusive of dynamics of which statics is a
special case.


Between statics and dynamics is kinetics. EM is the kinetics.
S*

Dynamics, of course, means time-varying. In EMF, or electromagnetics,
what varies is magnitude and/or polarity of the electric and magnetic
field. What you find "constant" about the fields (properly observed
as plural) is in their orthogonality (one field is building the other
as it decays in amplitude).

Well, language can be a barrier here when you say "around the cone."

I should have said the current flows around the cone parallel to its
base.


That doesn't happen.

73's
Richard Clark, KB7QHC



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Old December 4th 09, 07:35 PM posted to rec.radio.amateur.antenna
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Posts: 613
Default Faraday shields and radiation and misinterpretations

"Szczepan Bialek" wrote in
:

Between statics and dynamics is kinetics. EM is the kinetics.


This could either get very confusing, or very revealing, not sure which yet.
I found that no terms I knew fitted that well so I ended up using 'flux' and
'stasis' NOT to be confused with motion and stillness. By which I mean motion
and stillness are the phenomenon, but flux and stasis are what lies beyond,
in a pattern of information for want of better expression. To illustrate, a
tap turned to release a flow of water often shows a stationary pattern while
water is obviously flowing. That pattern is a stasis, but the water is not
still. I don't know how useful this is when resolving a distinction between
kinetics and dynamics, but it does look like we have to be careful about how
we use these terms or we might not know which we're talking about, the
standing pattern, or a manifest stillness. If we can't be clear on it we
might as well be trying to pin down the 'evanescence of soul'. (Richard
Clark, that was a good one, it's right up there with the better phrases from
Douglas Adams.)
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Old December 5th 09, 10:40 AM posted to rec.radio.amateur.antenna
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Default Faraday shields and radiation and misinterpretations


"Lostgallifreyan" wrote
. ..
"Szczepan Bialek" wrote in
:

Between statics and dynamics is kinetics. EM is the kinetics.


Should be kinematics (not kinetcs): "Branch of physics concerned with the
geometrically possible motion of a body or system of bodies, without
consideration of the forces involved. It describes the spatial position of
bodies or systems, their velocities, and their acceleration".

The kinematics describes motions without consideration what and why.

This could either get very confusing, or very revealing, not sure which
yet.


EM is the first step. No the next for the incompressible fluid. The electron
were discovered and the dynamics are done for them.

I found that no terms I knew fitted that well so I ended up using 'flux'
and
'stasis' NOT to be confused with motion and stillness. By which I mean
motion
and stillness are the phenomenon, but flux and stasis are what lies
beyond,
in a pattern of information for want of better expression. To illustrate,
a
tap turned to release a flow of water often shows a stationary pattern
while
water is obviously flowing. That pattern is a stasis, but the water is not
still. I don't know how useful this is when resolving a distinction
between
kinetics and dynamics, but it does look like we have to be careful about
how
we use these terms or we might not know which we're talking about, the
standing pattern, or a manifest stillness. If we can't be clear on it we
might as well be trying to pin down the 'evanescence of soul'. (Richard
Clark, that was a good one, it's right up there with the better phrases
from
Douglas Adams.)


For flows are also the flow kinematics and the flow dynamics.
"An accurate theory of electromagnetism, known as classical
electromagnetism, was developed by various physicists over the course of the
19th century, culminating in the work of James Clerk Maxwell, who unified
the preceding developments into a single theory and discovered the
electromagnetic nature of light. In classical electromagnetism, the
electromagnetic field obeys a set of equations known as Maxwell's equations,
and the electromagnetic force is given by the Lorentz force law. "

It seams that EM is the field kinematics.

S*




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