Richard Harrison wrote:
Cecil, W5DXP wrote:
"The following web page is representative of the side that asserts there
is virtually zero delay through a 75m loading coil. But the backers of
that argument have grown strangely silent of late."

Current does not jump off the rails in a coil.

Not disagreeing in general but just fine tuning a bit.
In an HF mobile loading coil, the EM waves are photonic
in nature so a few photons are capable of migrating to
adjacent turns - certainly not enough to cause the 3
nS delay through a 10 inch long 100 turn coil reported
by w8ji, but the effect is enough to roughly cut in half
the time taken for the current to negotiate the coil wire.

I have modeled a 75m Texas Bugcatcher coil at:

http://www.w5dxp.com/coil505u.EZ

The length of the wire used in that coil is ~48 feet.
A wavelength at 3.8 MHz is ~259 feet. So that 48 feet
equals about (360)(48/259) = ~67 degrees. Yet EZNEC
reports a phase shift of only ~38 degrees. The effect
of the interaction between adjacent coils increases the
velocity factor of the coil to roughly 1.8 times what it
would be if all the current were confined to the coil
wire. That's a VF increase from ~0.009 to ~0.016 but
certainly still magnitudes short of w8ji's reported
value of 0.988

The measured velocity factor as a function of the ratio
of coil-circumference/wavelength is presented by Kraus,
Figure 8-34 in the 3rd edition. Note that the phase
velocity is not a straight line function of circumference.

The velocity factor as a function of the ratio of
coil-diameter/wavelength has been plotted in Fig. 1
of: http://www.ttr.com/TELSIKS2001-MASTER-1.pdf
and is also not a straight-line function.
--
73, Cecil http://www.w5dxp.com

Cecil, W5DXP wrote:
"The measured velocity factor as a function of the ratio of
coil-circumference/wavelength is presented by Kraus, Figure 8-34 in the
3rd edition."

Yes. The older edition, posted briefly on the web, has a Fig. 7-19 which
also has VF`s found by Chu & Jackson, and by Bagby. They also found
propagation faster than c for some coil circumferences / wavelength.
Photons, massless at rest, can do that.

Best regards, Richard Harrison, KB5WZI

On Sun, 13 May 2007 07:23:15 -0500, (Richard
Harrison) wrote:

They also found
propagation faster than c for some coil circumferences / wavelength.
Photons, massless at rest, can do that.

Hi Richard,

This is beginning to descend into nonsense.

Forgive me, it has descended into nonsense long ago, what is happening
now is called porpoising (rising and falling deeper, repeatedly).

For instance the power in propagation cannot go faster than c for
anything - that is clearly absurd. Perhaps if you were to more deeply
cite your reference, then you would find what IS going faster in c has
no material content (this discussion is in the material being used by
you and I bet is the undisclosed topic of "group" velocity which is
thoroughly useless for 75M and subwavelength coils - again, there is a
world of difference between a coil and a helix in conventional
engineering usages).

Photons get a bad reputation here. There is no such thing as a
photon that is massless at rest - it is called an electron at a higher
energy level which definitely has mass (no doubt Cecil could Xerox an
obscure reference to prove it doesn't); OR it is rendered into a
massless Phonon, but Phonons by definition move (no such thing as rest
for them either); OR as a Plasmon, but Plasmons move too, but at a
different wavelength for the same frequency; OR as an Exciton....

The list of moving quasi-particles goes on, all of them moving. This
is something in distinct contrast to Cecil's threads that give only
the "appearance of motion."

73's
Richard Clark, KB7QHC

Cecil Moore wrote:
...
Not disagreeing in general but just fine tuning a bit.
In an HF mobile loading coil, the EM waves are photonic
in nature so a few photons are capable of migrating to
adjacent turns - certainly not enough to cause the 3
nS delay through a 10 inch long 100 turn coil reported
by w8ji, but the effect is enough to roughly cut in half
the time taken for the current to negotiate the coil wire.
...

Cecil:

What would you offer as to the "photonic-jump", the capacitance of the
adjacent turns with air serving as the dielectric?


Since inductance lags and capacitance leads, wouldn't the inductance
value between turns serve to offset this? And, the diameter of the wire
become a major factor in the phenomenon you propose?

What if a spiral wound faraday shield is placed between the turns?
Would we still see this "photonic-jump?"

Regards,
JS

John Smith I wrote:
What would you offer as to the "photonic-jump", the capacitance of the
adjacent turns with air serving as the dielectric?

When electrons are accelerated in a conductor, they
emit photons. Some photons are emitted from one turn
and migrate to the adjacent turn. One might think of
it as a few photons taking a shortcut. Another way
of saying the same thing is that the fields couple
turn-to-turn. The overall effect is to increase
the velocity factor of the coil by something like a
factor of two over the "threaded bolt" calculation.
However, the effect is still magnitudes too low to
explain the 100 turn, 3 nS coil delay described by
w8ji.

Standing wave current cannot be used to make valid
measurements about current amplitude "drops" across
or phase shifts through a loading coil. One must
instead figure out a way to get a traveling wave
flowing through the coil. Then the phase shift
becomes perfectly obvious.

I have taken Wes's helical coil from:

http://www.k6mhe.com/n7ws/Loaded%20antennas.htm

and modeled it with EZNEC. I then loaded the coil
with a 1250 ohm resistor to minimize reflected current
and took a look at the phase shift through the
coil. Turns out to be about 37 degrees at 7.15 MHz.
That makes it a delay of about 14.4 nS.

That coil512.EZ file can be downloaded from:

http://www.w5dxp.com/coil512.EZ
--
73, Cecil http://www.w5dxp.com

On Sun, 13 May 2007 11:02:24 -0500, Cecil Moore
wrote:

Aside from 100% error (actually more) for Wes' coil,

I have taken Wes's helical coil from:
http://www.k6mhe.com/n7ws/Loaded%20antennas.htm
and modeled it with EZNEC. ...
That coil512.EZ file can be downloaded from:

is distinctly false.

Richard Clark wrote:
On Sun, 13 May 2007 11:02:24 -0500, Cecil Moore
wrote:

Aside from 100% error (actually more) for Wes' coil,

I don't understand but will be glad to correct
any error.

I have taken Wes's helical coil from:
http://www.k6mhe.com/n7ws/Loaded%20antennas.htm
and modeled it with EZNEC. ...
That coil512.EZ file can be downloaded from:

is distinctly false.

In what way?
--
73, Cecil http://www.w5dxp.com

On Sun, 13 May 2007 12:49:03 -0500, Cecil Moore
wrote:

In what way?

Abandon your Xerox ethic and actually read your reference. This
advice would work for other citations you copy off too.

Richard Clark wrote:
Abandon your Xerox ethic and actually read your reference. This
advice would work for other citations you copy off too.

Here's what it says:
"Case 3 uses a model similar to the other two cases, except the
three-segment load wire is replaced by a wire coil ("distributed load")
consisting of sixteen turns of 12 AWG wire, spaced 0.5 inch between
adjacent turns, for a total height (length) of eight inches. The coil is
centered on the length of the monopole and the monopole is brought to
resonance by using the resonating function of MultiNEC to adjust the
radius of the coil. Eight, single segment wires arranged in octagonal
form approximate each turn of the circular coil, for a total of 128
single-segment wires."

Exactly what did I miss?
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
...
Standing wave current cannot be used to make valid
measurements about current amplitude "drops" across
or phase shifts through a loading coil. One must
instead figure out a way to get a traveling wave
flowing through the coil. Then the phase shift
becomes perfectly obvious.
...

So, "something" roughly related to [speed-of-light -
velocity-factor-of-conductor = phase-shift] should be at play (since
photons are speed of light and the rf wave is limited by the VF) ???

Regards,
JS