On 19 mayo, 15:04, Cecil Moore wrote:
On May 19, 4:05*am, Wimpie wrote:

Regarding your helical; I don't have Eznec. Maybe you can use some
screenshots from it, put some comment to it and put that on website,
so we can view it.

Here it is:http://www.w5dxp.com/teaser2.JPG
--
73, Cecil, w5dxp.com

Hello Cecil,

Your circuit (lumped inductance example) with 100V input into 72uH
with 2570 Ohms load):

From lumped circuit simulation (Beige Bag PSPICE, version 4
professional):

I_source = 32mA, -35 degrees
I_load = 32mA, -35 degrees

This agrees with hand calculation, all phase with respect to input
voltage.

From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms
Simulation carried out with same PSPICE package without using
transmission line sections:

I_source = 38mA, -1.5 degrees
I_load = 38mA, -44 degrees.

Total required time for setting up the simulations and guessing the
parasitic components to simulate the actual inductor behavior: about
15 minutes.

As you can see good agreement without using any of the photons, speed
of light, momentum and other issues, just lumped circuit simulation
where some parasitics are added. Of course a can make a better match,
but this doesn't contribute to the discussion.

I hope that some followers or contributors will do the same simulation
in a lumped circuit simulator, so that we don't arrive in a discussion
that I am cheating.

Wim
PA3DJS
www.tetech.nl

On May 19, 9:03*am, Wimpie wrote:
From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms

You just proved one of my points. Inventing impedors that do not exist
in reality in order to rationalize the real-world delay through a real-
world loading coil is exactly what I have been complaining about. Are
the imaginary lumped-circuit capacitors, to which you are forced to
resort, part of the actual impedance in reality or a figment of your
imagination?

http://hamwaves.com/antennas/inductance/corum.pdf
"The concept of coil 'self-capacitance' is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior." About the capacitors you added
above it says: "Of course, this is merely a statistical determination
appropriate for computations ... and *not at all a physical
quantity*."

The reason that the source voltage and source current are in phase in
the example is because the load resistor equals the Z0 of the coil
which is functioning in transmission line mode with a VF = 0.019, i.e.
like a transmission line, it is indeed 0.1167 wavelengths long
electrically. I have verified such (within a certain degree of
accuracy) through bench experiments.
--
73, Cecil, w5dxp.com

On May 19, 11:25*am, Cecil Moore wrote:
On May 19, 9:03*am, Wimpie wrote:

From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms

You just proved one of my points. Inventing impedors that do not exist
in reality in order to rationalize the real-world delay through a real-
world loading coil is exactly what I have been complaining about. Are
the imaginary lumped-circuit capacitors, to which you are forced to
resort, part of the actual impedance in reality or a figment of your
imagination?

http://hamwaves.com/antennas/inductance/corum.pdf
"The concept of coil 'self-capacitance' is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior." About the capacitors you added
above it says: "Of course, this is merely a statistical determination
appropriate for computations ... and *not at all a physical
quantity*."

The reason that the source voltage and source current are in phase in
the example is because the load resistor equals the Z0 of the coil
which is functioning in transmission line mode with a VF = 0.019, i.e.
like a transmission line, it is indeed 0.1167 wavelengths long
electrically. I have verified such (within a certain degree of
accuracy) through bench experiments.
--
73, Cecil, w5dxp.com

First I'll point out that the model Wim used doesn't match "the
concept of coil self-capacitance," so it's not clear that the rest of
what you wrote is relevant.

Now, what do you do about your coils when you discover that they do
NOT behave like a TEM transmission line? Indeed they do not; it's
pretty easy to verify from measurements on real coils and real
circuits. It seems like now you are stuck, because you (seem to) have
a lot of trouble looking at a circuit and understanding what's really
important and what isn't, with regard to performance in a particular
application. Sometimes it's appropriate to use a model that goes well
beyond a simple transmission line model of a coil; sometimes the
simple transmission line model is far more complex than you need. See
Wim's previous posting about the value of understanding that.

FWIW, I understand perfectly well where the capacitances Wim put into
his model come from. I know exactly how I would estimate them from a
particular physical configuration, and I suppose Wim does something
very similar to what I would. They come very much from the real
physical world, not from our imaginations.

Cheers,
Tom

On 5/19/2011 2:26 PM, K7ITM wrote:
On May 19, 11:25 am, Cecil wrote:
On May 19, 9:03 am, wrote:

From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms

You just proved one of my points. Inventing impedors that do not exist
in reality in order to rationalize the real-world delay through a real-
world loading coil is exactly what I have been complaining about. Are
the imaginary lumped-circuit capacitors, to which you are forced to
resort, part of the actual impedance in reality or a figment of your
imagination?

http://hamwaves.com/antennas/inductance/corum.pdf
"The concept of coil 'self-capacitance' is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior." About the capacitors you added
above it says: "Of course, this is merely a statistical determination
appropriate for computations ... and *not at all a physical
quantity*."

The reason that the source voltage and source current are in phase in
the example is because the load resistor equals the Z0 of the coil
which is functioning in transmission line mode with a VF = 0.019, i.e.
like a transmission line, it is indeed 0.1167 wavelengths long
electrically. I have verified such (within a certain degree of
accuracy) through bench experiments.
--
73, Cecil, w5dxp.com

First I'll point out that the model Wim used doesn't match "the
concept of coil self-capacitance," so it's not clear that the rest of
what you wrote is relevant.

Now, what do you do about your coils when you discover that they do
NOT behave like a TEM transmission line? Indeed they do not; it's
pretty easy to verify from measurements on real coils and real
circuits. It seems like now you are stuck, because you (seem to) have
a lot of trouble looking at a circuit and understanding what's really
important and what isn't, with regard to performance in a particular
application. Sometimes it's appropriate to use a model that goes well
beyond a simple transmission line model of a coil; sometimes the
simple transmission line model is far more complex than you need. See
Wim's previous posting about the value of understanding that.

FWIW, I understand perfectly well where the capacitances Wim put into
his model come from. I know exactly how I would estimate them from a
particular physical configuration, and I suppose Wim does something
very similar to what I would. They come very much from the real
physical world, not from our imaginations.

Cheers,
Tom

And, I find the lack of stray capacitance in Cecil's model much harder
to believe than the presence of them in Wim's model.

John

On 19 mayo, 20:25, Cecil Moore wrote:
On May 19, 9:03*am, Wimpie wrote:

From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms

You just proved one of my points. Inventing impedors that do not exist
in reality in order to rationalize the real-world delay through a real-
world loading coil is exactly what I have been complaining about. Are
the imaginary lumped-circuit capacitors, to which you are forced to
resort, part of the actual impedance in reality or a figment of your
imagination?

http://hamwaves.com/antennas/inductance/corum.pdf
"The concept of coil 'self-capacitance' is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior." About the capacitors you added
above it says: "Of course, this is merely a statistical determination
appropriate for computations ... and *not at all a physical
quantity*."

The reason that the source voltage and source current are in phase in
the example is because the load resistor equals the Z0 of the coil
which is functioning in transmission line mode with a VF = 0.019, i.e.
like a transmission line, it is indeed 0.1167 wavelengths long
electrically. I have verified such (within a certain degree of
accuracy) through bench experiments.
--
73, Cecil, w5dxp.com

Cecil,

Lumped circuit approach gives a good solution for your brainteaser
(maybe against your expectations or hope). It is just distributed
capacitance to ground that can be concentrated into 1 or more
capacitors if you are well below the first resonance frequency.

In a real application when using a lumped 72uH inductor for
calculations, one will find out that the capacitors for a certain
application (for example pi-filter section) have to be somewhat
smaller then based on the lumped circuit calculation.

Regarding transmission line behavior
It is the reason to mention "without using transmission line
sections". Because my PSPICE package also allows use of transmission
lines, if convenient I use them. Do you know how I made my first guess
for the capacitors? Just by using transmission line theory. BTW,
what is the wire length of the inductor in your HF rig (for 4 MHz
band)? It is very likely well below the length for the bugcatcher
example.

Did you know that many delay lines were/are made by using multiple CLC
sections (for example used in oscilloscopes)?

Again, look to the circuits of your rig, do you really think that the
design is carried out by modelling each component as a transmission
line. The answer is no (for sure).

We have various religions around the globe; I think we don't need
another one based on transmission lines! Maybe for you it was
wonderful to explore transmission line theory, but for RF Engineers/
Designers (antenna designers included), it is just one of their means
to get the job done.

Wim
PA3DJS
www.tetech.nl

On 19 mayo, 20:25, Cecil Moore wrote:
On May 19, 9:03*am, Wimpie wrote:

From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms

You just proved one of my points. Inventing impedors that do not exist
in reality in order to rationalize the real-world delay through a real-
world loading coil is exactly what I have been complaining about. Are
the imaginary lumped-circuit capacitors, to which you are forced to
resort, part of the actual impedance in reality or a figment of your
imagination?

http://hamwaves.com/antennas/inductance/corum.pdf
"The concept of coil 'self-capacitance' is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior." About the capacitors you added
above it says: "Of course, this is merely a statistical determination
appropriate for computations ... and *not at all a physical
quantity*."

The reason that the source voltage and source current are in phase in
the example is because the load resistor equals the Z0 of the coil
which is functioning in transmission line mode with a VF = 0.019, i.e.
like a transmission line, it is indeed 0.1167 wavelengths long
electrically. I have verified such (within a certain degree of
accuracy) through bench experiments.
--
73, Cecil, w5dxp.com

Cecil,

Lumped circuit approach gives a good solution for your brainteaser
(maybe against your expectations or hope). It is just distributed
capacitance to ground that can be concentrated into 1 or more
capacitors if you are well below the first resonance frequency.

In a real application when using a lumped 72uH inductor for
calculations, one will find out that the capacitors for a certain
application (for example pi-filter section) have to be somewhat
smaller then based on the lumped circuit calculation.

Regarding transmission line behavior
It is the reason to mention "without using transmission line
sections". Because my PSPICE package also allows use of transmission
lines, if convenient I use them. Do you know how I made my first guess
for the capacitors? Just by using transmission line theory. BTW,
what is the wire length of the inductor in your HF rig (for 4 MHz
band)? It is very likely well below the length for the bugcatcher
example.

Did you know that many delay lines were/are made by using multiple CLC
sections (for example used in oscilloscopes)?

Again, look to the circuits of your rig, do you really think that the
design is carried out by modelling each component as a transmission
line. The answer is no (for sure).

We have various religions around the globe; I think we don't need
another one based on transmission lines! Maybe for you it was
wonderful to explore transmission line theory, but for RF Engineers/
Designers (antenna designers included), it is just one of their means
to get the job done.

Wim
PA3DJS
www.tetech.nl

On 19 mayo, 20:25, Cecil Moore wrote:
On May 19, 9:03*am, Wimpie wrote:

From simulation, but now a pi filter C=6pF, L=72u, C=6pF, load = 2570
Ohms

You just proved one of my points. Inventing impedors that do not exist
in reality in order to rationalize the real-world delay through a real-
world loading coil is exactly what I have been complaining about. Are
the imaginary lumped-circuit capacitors, to which you are forced to
resort, part of the actual impedance in reality or a figment of your
imagination?

http://hamwaves.com/antennas/inductance/corum.pdf
"The concept of coil 'self-capacitance' is an attempt to circumvent
transmission line effects on small coils when the current distribution
begins to depart from its DC behavior." About the capacitors you added
above it says: "Of course, this is merely a statistical determination
appropriate for computations ... and *not at all a physical
quantity*."

The reason that the source voltage and source current are in phase in
the example is because the load resistor equals the Z0 of the coil
which is functioning in transmission line mode with a VF = 0.019, i.e.
like a transmission line, it is indeed 0.1167 wavelengths long
electrically. I have verified such (within a certain degree of
accuracy) through bench experiments.
--
73, Cecil, w5dxp.com

Cecil,

Lumped circuit approach gives a good solution for your brainteaser
(maybe against your expectations or hope). It is just distributed
capacitance to ground that can be concentrated into 1 or more
capacitors if you are well below the first resonance frequency.

In a real application when using a lumped 72uH inductor for
calculations, one will find out that the capacitors for a certain
application (for example pi-filter section) have to be somewhat
smaller then based on the lumped circuit calculation.

Regarding transmission line behavior
It is the reason to mention "without using transmission line
sections". Because my PSPICE package also allows use of transmission
lines, if convenient I use them. Do you know how I made my first guess
for the capacitors? Just by using transmission line theory. BTW,
what is the wire length of the inductor in your HF rig (for 4 MHz
band)? It is very likely well below the length for the bugcatcher
example.

Did you know that many delay lines were/are made by using multiple CLC
sections (for example used in oscilloscopes)?

Again, look to the circuits of your rig, do you really think that the
design is carried out by modelling each component as a transmission
line. The answer is no (for sure).

We have various religions around the globe; I think we don't need
another one based on transmission lines! Maybe for you it was
wonderful to explore transmission line theory, but for RF Engineers/
Designers (antenna designers included), it is just one of their means
to get the job done.

Wim
PA3DJS
www.tetech.nl

On May 19, 3:27*pm, Wimpie wrote:
We have various religions around the globe; I think we don't need
another one based on transmission lines!

Actually, what I am attempting to do is discourage your lumped-circuit
religion, where a 100 uH, 10" long coil, can propagate an RF signal in
3 ns, and move you guys closer to the reality of Maxwell's equations.
--
73, Cecil, w5dxp.com

On 19 mayo, 23:23, Cecil Moore wrote:
On May 19, 3:27*pm, Wimpie wrote:

We have various religions around the globe; I think we don't need
another one based on transmission lines!

Actually, what I am attempting to do is discourage your lumped-circuit
religion, where a 100 uH, 10" long coil, can propagate an RF signal in
3 ns, and move you guys closer to the reality of Maxwell's equations.
--
73, Cecil, w5dxp.com

Hello Cecil,

I am not addicted to "lumped circuits", I just use the appropriate
model. Many amateurs built and / or designed their own HF PA (and
other circuitry relevant to the hobby). Do you really think that they
all considered every component to be a transmission line?

Transmission lines in general.
I agree with Tom, "Transmission line approach" is also just a model
with limited validity. It all depends on the Engineer/Designer whether
to use it or misuse it.


Wim
PA3DJS
www.tetech.nl

On May 19, 5:22*pm, Wimpie wrote:
Many amateurs built and / or designed their own HF PA (and
other circuitry relevant to the hobby). Do you really think that they
all considered every component to be a transmission line?

You apparently have not comprehended what I am trying to say. When one
is designing a piece of equipment, whatever works, works. Please don't
confuse design/analysis techniques and rule-of-thumb shortcuts with
the underlying principles supporting the laws of physics. Enumerating
all the design techniques in the world does not tell us anything about
what is happening in reality to those photonic fields and waves that
necessarily must obey the laws of physics.

Even DC impulses travel at the speed of light. Electron drift velocity
is much, much slower than the speed of light. Everything EM is
photonic in nature. Photons must obey the laws of physics known to
exist for photons. There is simply no getting around that fact. All of
the magical thinking, hand-waving, design/analysis shortcuts, and
rules-of-thumb in the world are not going to change those facts of
physics.

If you do not understand those physical limitations (including. the
difference between the two IEEE definitions of impedance) you will
never understand what is actually happening in reality inside (or
outside of) an RF source. I don't know what else to say.
--
73, Cecil, w5dxp.com