wrote :
That is incorrect for the conditions we are outlining, and it is
misleading Cecil. It has him lost in a world of reflections.

What is causing the misleading part is: THE LUMPED-CIRCUIT
MODEL FAILS IN THE PRESENCE OF STANDING WAVES!

There is no virtually no difference in phase delay in current at each
end of a relatively compact inductor.

Is a 75m bugcatcher coil a "relatively compact indictor"? If you say
yes, you are stuck with its measured delay. If you say no, then we
are not discussing the typical amateur radio mobile loading coil.

Of course, one turn on a toroid is going to exhibit the characteristics
you are presenting. But that is not a typical bugcatcher coil either.

The Tesla coil, by definition of how it works, violates all boundaries
of the examples myself and others are giving Cecil. It does not apply
to the discussion at all.

False: A 75m bugcatcher coil used as a 1/4WL resonator on
9-10 MHz meets the minimum requirements for a Tesla coil.
It uses 1/6 wavelength of wire on 75m. I'll bet it would
certainly arc at a kilowatt.

The typical minimum Tesla system is a coil with a top hat sphere.
It looks a lot like your 160m mobile antenna. :-)

It is not operated at a fraction of
self-resonance as people SHOULD know a good mobile loading coil is.

A 75m bugcatcher coil is operating close enough to its self-resonant
frequency that the self-resonant effects are certainly present.

A 75m bugcatcher coil can be considered to be a lumped circuit
impedance at 60 Hz but certainly not at 4000000 Hz. In fact,
that is the whole question. At what frequency can the lumped
circuit model be validly used on a 75m bugcatcher coil? I'm
willing to bet that frequency is lower than 1000000 Hz.

It has no bearing at all on the discussion, ...

Wishful thinking on your part.
..
In fact, a Tesla coil has more in common with a cavity resonator
than it does with a conventional inductor."

A 75m bugcatcher coil has more in common with a cavity resonator
than it does with your lumped circuit inductance.

"at its operating frequency, a Tesla coil is NOT a
lumped-element induction coil".

Neither is a 75m bugcatcher coil.

Everyone in the conversation has been very careful to clearly establish
the boundary conditions that the behavior we are talking about is
significantly below self-resonance, an inductor of compact form factor,
and an inductor of good design.

A 75m bugcatcher coil used on 4 MHz is NOT significantly below
the self-resonant frequency of 9-10 MHz.

THE LUMPED-CIRCUIT MODEL FAILS IN A STANDING
WAVE ENVIRONMENT! In the face of that simple technical fact,
all other discussion is moot. Anyone wishing to validly model a
75m bugcatcher coil used on a mobile antenna is forced to choose
a model that does not presuppose faster than light wave travel
through a 75m bugcatcher coil. It's as simple as that.

Tom, with a straight face, I want you to assert that the RF waves
on a 75m bugcatcher mobile antenna are traveling faster than
the speed of light. If it takes 125 nanoseconds for the forward
current wave to make it from the end of the antenna and back
to the feedpoint, then the lumped-circuit model yields invalid
results. TDR anyone?
--
73, Cecil, W5DXP