On Fri, 14 Dec 2007 05:18:03 -0800, "Roger Sparks"
wrote:

That IS what I said. Think of the velocity as a moving wall, with the
capacitor charged behind the wall, uncharged in front of the moving wall.
....
Be real. This experiment can be performed, and the DC switched as
frequently as desired. How square the wave front will be depends upon real
world factors.

Go to a transmission line characteristics table and use the formula to
compare Zo, capacity per length, and line velocity. It will amaze you.

Hi Roger,

Take a deep breath, exhale, give what's above some more thought in
light of many objections.

Now, tells us just what significance any of this has in relation to
already well established line mechanics? It certainly isn't different
within the confines of its limitations if that is what you are trying
to impress upon the group. I suppose for a mental short-cut it has
some appeal, we get too many theories here based on approximations to
stricter math. One such example is when an equation of approximation
has forgotten the underlying |absolute value| and suddenly an inventor
arrives with a "new" theory that discovers uses for negative
solutions.

Further, there is nothing DC about it at all. DC is either static
(and in spite of Arthur's corruption of the term, that means no
movement whatever) or it is a constant unvarying current. A
succession of distributed capacitors rules unvarying current out (and
if it isn't already obvious, those unmentioned distributed inductors
in one of your links do too) - hence the step, hence the infinity of
waves, and from this, real world dispersion which kills the step
enough to make that varying current apparent enough so as to remove
all doubt.

73's
Richard Clark, KB7QHC

Keith Dysart wrote:
On Dec 14, 9:40 am, Cecil Moore wrote:
AI4QJ wrote:
If it were possible for the source to provide DC
current at c, then the DC current moves at c.
The step function from zero to DC contains a lot
of frequencies. I suspect photons are involved
at the leading edge of the DC pulse.

"Suspect" -- Perhaps like Inspector Clouseau?

Humour aside, for transmission lines you should
stick to charge, and distributed capacitance and
inductance. This model is aptly capable and has
no difficulties as the frequency drops so low that
it becomes indistinguishable from DC.

Why bother with photons? Only at the leading
edge, you say. What explains the rest?

Where is the energy stored? In the capacitance
and inductance. Why not use the tools that work?

Why try to force fit photons?

....Keith

If we look at a tree from the north side, and then look at the same tree
from the south side, we have looked at only one tree but we have seen it
from two perspectives.

Zo = sq. rt. L/C = 1/cC

Inductance can be described as L = 1/((c^2)*C) (inductance per length)

So is the energy stored in the inductance or in the capacitance.

Two ways of looking at the same tree.

73, Roger, W7WKB

Richard Clark wrote:
On Fri, 14 Dec 2007 05:18:03 -0800, "Roger Sparks"
wrote:

That IS what I said. Think of the velocity as a moving wall, with the
capacitor charged behind the wall, uncharged in front of the moving wall.
....
Be real. This experiment can be performed, and the DC switched as
frequently as desired. How square the wave front will be depends upon real
world factors.

Go to a transmission line characteristics table and use the formula to
compare Zo, capacity per length, and line velocity. It will amaze you.

Hi Roger,

Take a deep breath, exhale, give what's above some more thought in
light of many objections.

Now, tells us just what significance any of this has in relation to
already well established line mechanics? It certainly isn't different
within the confines of its limitations if that is what you are trying
to impress upon the group. I suppose for a mental short-cut it has
some appeal, we get too many theories here based on approximations to
stricter math. One such example is when an equation of approximation
has forgotten the underlying |absolute value| and suddenly an inventor
arrives with a "new" theory that discovers uses for negative
solutions.

Further, there is nothing DC about it at all. DC is either static
(and in spite of Arthur's corruption of the term, that means no
movement whatever) or it is a constant unvarying current. A
succession of distributed capacitors rules unvarying current out (and
if it isn't already obvious, those unmentioned distributed inductors
in one of your links do too) - hence the step, hence the infinity of
waves, and from this, real world dispersion which kills the step
enough to make that varying current apparent enough so as to remove
all doubt.

73's
Richard Clark, KB7QHC

Hi Richard,

The math seems to work, but if you have no use for it, disregard it. On
the other hand, if another perspective of electro magnetics that
conforms to traditional mathematics can provide additional insight, use it.

I am surprised at your criticism in using DC. To me, a square wave is
DC for a short time period. Is the observation that a square wave can
be described as a series of sine waves troubling to you? Perhaps the
observation that a square wave might include waves of a frequency so
high that they would not be confined in a normal transmission line is
surprising or troubling to you?

My goal is to better understand electromagnetic phenomena. You have
given some very astute insight many times in the past and thanks for
that. Negative comment is equally valuable, but sometimes a little
harder to swallow.

73, Roger, W7WKB

On Dec 14, 9:40 am, Cecil Moore wrote:
AI4QJwrote:
If it were possible for the source to provide DC
current at c, then the DC current moves at c.

The step function from zero to DC contains a lot
of frequencies. I suspect photons are involved
at the leading edge of the DC pulse.
--
73, Cecil http://www.w5dxp.com

Right, the step function has a number of sinusoids associated with it
which are affected by Zo and that was already addressed. Richard's
challenge was to address the velocity of DC at steady state, after the
transients from the step died down.

On Fri, 14 Dec 2007 09:45:04 -0800, Roger wrote:

Hi Richard,

The math seems to work, but if you have no use for it, disregard it. On
the other hand, if another perspective of electro magnetics that
conforms to traditional mathematics can provide additional insight, use it.

Hi Roger,

This does not answer why TWO mathematics (both traditional) are
needed, especially since one is clearly an approximation of the other,
and yet offers no obvious advantage. I've already spoken to the
hazards of approximations being elevated to proof by well-meaning, but
slightly talented amateurs.

I am surprised at your criticism in using DC. To me, a square wave is
DC for a short time period.

This single statement, alone, is enough to be self-negating. You
could as easily call a car with a standard stick shift an automatic
between the times you use the clutch - but that won't sell cars, will
it?

Is the observation that a square wave can
be described as a series of sine waves troubling to you? Perhaps the
observation that a square wave might include waves of a frequency so
high that they would not be confined in a normal transmission line is
surprising or troubling to you?

DC as sine waves is not a contradiction on the face of it? DC that
consists of waves of a frequency so high that it would not be confined
in a normal transmission line is very surprising, isn't it?

Would it surprise you to find your batteries in their packaging direct
from the store are radiating on the shelf? They are DC, are they not?
If the arguments of your sources works for an infinite line, they must
be equally true for an infinitesimal open line. When your headlights
are on, do they set off radar detectors in cars nearby because of the
high frequencies now associated with DC?

My goal is to better understand electromagnetic phenomena. You have
given some very astute insight many times in the past and thanks for
that. Negative comment is equally valuable, but sometimes a little
harder to swallow.

The pollution of terms such as DC to serve a metaphor that replaces
conventional line mechanics is too shallow glass to attempt to quench
any thirst.

The puzzle here is the insistence on hugging DC, when every element of
all of your links could as easily substitute Stepped Wave and remove
objections. The snake in the wood pile is once having fudged what DC
means, it is only a sideways argument away from rendering the term DC
useless. Is the term Stepped Wave (the convention) anathema for a
leveraging the novel origination (the invention) of DC Wave?

73's
Richard Clark, KB7QHC

On Dec 14, 11:10 am, Cecil Moore wrote:
Keith Dysart wrote:
Why bother with photons?

Because it is impossible for electrons to move
fast enough to explain the measured results.
There is indeed a "DC" *wavefront* moving at
the speed of light adjusted for VF. Electrons
cannot move that fast. What is happening is
that fast photons are skipping from slow electron
to slow electron.

Do photons also explain how sound can move
at a 1000 ft/s, while the air molecules barely
move at all?

No? Not clear then why they are needed for
electrons.

....Keith

Roger wrote:
I am surprised at your criticism in using DC. To me, a square wave is
DC for a short time period. Is the observation that a square wave can
be described as a series of sine waves troubling to you? Perhaps the
observation that a square wave might include waves of a frequency so
high that they would not be confined in a normal transmission line is
surprising or troubling to you?

Anyone who has ever tried to send a DC pulse down a long
transmission line has seen AC ringing at the other end.
--
73, Cecil http://www.w5dxp.com

wrote:
Right, the step function has a number of sinusoids associated with it
which are affected by Zo and that was already addressed. Richard's
challenge was to address the velocity of DC at steady state, after the
transients from the step died down.

Another steady-state Catch-22, one of many.
--
73, Cecil http://www.w5dxp.com

Richard Clark wrote:
The puzzle here is the insistence on hugging DC, when every element of
all of your links could as easily substitute Stepped Wave and remove
objections.

How about "continuous wave" for Morse code?
--
73, Cecil http://www.w5dxp.com

Keith Dysart wrote:
Do photons also explain how sound can move
at a 1000 ft/s, while the air molecules barely
move at all?

No, mechanical longitudinal waves are well understood.
It is impossible for them to achieve the speed of light.

No? Not clear then why they are needed for
electrons.

Do you think electrons support mechanical waves?
The fields of TEM waves consist of photons traveling
at the speed of light.
--
73, Cecil http://www.w5dxp.com