Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:

If the pulse is not at the frequency of operation, the results
are hardly useful at all since the response of the loading coil
is frequency dependent.

So we are back to the original question.

It's clear that you are still back at that question. That doesn't
necessarily apply to everyone else though. What I would suggest is
that you go back, re-read, and try to undertstand the post, in
particular the parts you deleted.

73, ac6xg

Phase Shift through a 75m Texas Bugcatcher Coil
 

Jim Kelley wrote:
It's clear that you are still back at that question. That doesn't
necessarily apply to everyone else though. What I would suggest is that
you go back, re-read, and try to undertstand the post, in particular the
parts you deleted.

What's to understand? If the measurements are not made
at the operating frequency, there is no way to prove
that they are valid.

Both the velocity factor and the characteristic
impedance of a loading coil change dramatically
with frequency.

What is wrong with using a sinusoidal traveling
wave to measure the phase shift through a coil
at its frequency of operation?
--
73, Cecil, w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:
Jim Kelley wrote:

It's clear that you are still back at that question. That doesn't
necessarily apply to everyone else though. What I would suggest is
that you go back, re-read, and try to undertstand the post, in
particular the parts you deleted.


What's to understand? If the measurements are not made
at the operating frequency, there is no way to prove
that they are valid.

It appears that you would benefit from an understanding of the
spectral nature of broadband pulses.

Both the velocity factor and the characteristic
impedance of a loading coil change dramatically
with frequency.

What is wrong with using a sinusoidal traveling
wave to measure the phase shift through a coil
at its frequency of operation?

You need to be able to demonstrate that attaching a load resistor to a
standing wave antenna in order to turn it into a traveling wave
antenna does not dramatically change the characteristics.

73, Jim AC6XG

Phase Shift through a 75m Texas Bugcatcher Coil
 

Jim Kelley wrote:
It appears that you would benefit from an understanding of the spectral
nature of broadband pulses.

I understand Fourier analysis. What is the benefit
of using a lot of frequencies when you could use
the frequency of interest?

You need to be able to demonstrate that attaching a load resistor to a
standing wave antenna in order to turn it into a traveling wave antenna
does not dramatically change the characteristics.

Proving a negative is impossible. If you are asserting
that attaching a load resistor to a loading coil dramatically
changes the characteristics, the onus of proof is upon
you.
--
73, Cecil, w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:

What is the benefit
of using a lot of frequencies when you could use
the frequency of interest?

Your memory is growing short. Do you not remember challenging me to
do that very thing - claiming it was impossible? I said I would use
pulses, then you said it wouldn't work, bla bla bla. Circuitious,
isn't it.

If you are asserting
that attaching a load resistor to a loading coil dramatically
changes the characteristics, the onus of proof is upon
you.

It should be readily apparent to just about anyone that one does in
fact significantly alter the characteristics of a system by changing
it from one which has a reflection at the end to one which doesn't.

73, ac6xg

Phase Shift through a 75m Texas Bugcatcher Coil
 

Jim Kelley wrote:
Cecil Moore wrote:

What is the benefit
of using a lot of frequencies when you could use
the frequency of interest?

Your memory is growing short. Do you not remember challenging me to do
that very thing - claiming it was impossible? I said I would use
pulses, then you said it wouldn't work, bla bla bla. Circuitious, isn't
it.

No, I'm still saying the same thing. What is the benefit
of using a lot of frequencies when you could use the
frequency of interest?

If you are asserting
that attaching a load resistor to a loading coil dramatically
changes the characteristics, the onus of proof is upon
you.

It should be readily apparent to just about anyone that one does in fact
significantly alter the characteristics of a system by changing it from
one which has a reflection at the end to one which doesn't.

So I guess it is up to you to prove that the system is
somehow non-linear in one direction only. Good luck on
that one.

A non-terminated Rhombic has both forward and reflected
currents. A terminated Rhombic has only forward current.
Exactly how is the physics of the Rhombic changed by
adding a termination resistor?
--
73, Cecil, w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

Richard Clark, KB7QHC wrote:
"Now do you have actual citations that support Phase Velocity carrying
information and energy at faster than light speeds?"

Yes, but I don`t necessarily believe them. Wikipedia gives recent
examples of apparent violations of the limit imposed by the speed of
light. However, I infer the editor did not believe them as proving a
violation.

On page 253 of "Transmission Lines, Antennas, and Wave Guides" by King,
Mimno, and Wing:

"This means that the phase velocity vpg is greater in the TM 0,1 mode
than in the TEM type and, therefore, greater than 3x10 to the 8th power
m/sac."

The 3rd edition of "Antennas" by Kraus, et al on page 255 is found Fig.
8-34 showing phase velocity versus helix circumference. Some helices are
shown with phase velocities exceeding the speed of light.

I was one who didn`t believe W8JI`s loading coil instantly induced
energy from one end to the other by magnetic induction.

Best regards, Richard Harrison, KB5WZI

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:
A non-terminated Rhombic has both forward and reflected
currents. A terminated Rhombic has only forward current.
Exactly how is the physics of the Rhombic changed by
adding a termination resistor?

The same physics applies to all antennas, Cecil. Would you assert
that fact gives all antennas the same characteristics?

But here's the point. Your claim is that the coil as you have modeled
it, performs the same in EZNEC as it does when it is employed as part
of a 75 meter Bugcatcher antenna. At the same time you want to claim
that there's no other way to do such testing.

It's not a reasonable viewpoint, Cecil. But you're entitled to it and
I'm happy if you want to go on having it. :-)

73, Jim AC6XG

Phase Shift through a 75m Texas Bugcatcher Coil
 

Jim Kelley wrote:
But here's the point. Your claim is that the coil as you have modeled
it, performs the same in EZNEC as it does when it is employed as part of
a 75 meter Bugcatcher antenna. At the same time you want to claim that
there's no other way to do such testing.

No, you missed the point. If there is any other way
to do such testing, please present it. Valid testing
methods are what we are lacking.
--
73, Cecil http://www.w5dxp.com