Gene Fuller wrote:
My question is why you feel there is anything of significance or
anything for the "gurus" to ponder.

Hopefully, I answered that question in my other posting. If one
wants to measure phase shift using a traveling wave current, one
measures the phase shift between two points.

If one wants to measure the phase shift using a standing wave
current, one measures the amplitudes at two points and subtracts
the arc-cosines of the normalized amplitude values.

You said essentially the same thing in your earlier posting -
that there is no phase information in the standing wave current
phase and all the phase information is in the amplitude values.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote in message
m...
You said essentially the same thing in your earlier posting -
that there is no phase information in the standing wave current
phase and all the phase information is in the amplitude values.

thats the basic problem in this whole discussion. you are all talking about
the same thing, just using different notation and incomplete statements so
that none of you understands exactly what the others are trying to talk
about... when really you are all saying the same thing. its kind of like
after i graduated from college with an ee degree and my sister graduated
from an air force basic electronics course, she tried to ask me something
about currents in a transistor and i saw it all backwards... well of course
she was talking electron flow and i was talking hole flow. we both got the
same result but the notation was all different.

so, now i will raise my voice...

STOP THIS PETTY BICKERING AND GET OUT THERE AND USE AN ANTENNA INSTEAD OF
ARGUING ABOUT WHY THEY DON"T WORK THEY WAY YOU THINK THEY SHOULD!

Dave wrote:
... when really you are all saying the same thing.

Unfortunately, we are not all saying the same thing.
W7EL and W8JI are saying that using standing wave
current phase to make a phase shift measurement is
a valid approach. They keep reporting their results of
using such an approach as if it were a valid thing to
do. When those useless phase measurements are discarded,
the technical picture becomes a lot clearer.

I, and others, are saying that using a signal with
unchanging phase will not and cannot tell one anything
about any phase shift. There is no phase information
contained in the standing wave phase. All of the phase
information is contained in the standing wave magnitude.

I'm building a web page about this subject. The initial
graphic is at: http://www.qsl.net/w5dxp/travstnd.GIF

Note that for a standing wave current, the only thing
changing with length is magnitude. The flat phase line
of the standing wave current is completely useless for
making phase measurements.
--
73, Cecil http://www.qsl.net/w5dxp

Dave wrote:
thats the basic problem in this whole discussion. you are all talking about
the same thing, just using different notation and incomplete statements so
that none of you understands exactly what the others are trying to talk
about... when really you are all saying the same thing. its kind of like
after i graduated from college with an ee degree and my sister graduated
from an air force basic electronics course, she tried to ask me something
about currents in a transistor and i saw it all backwards... well of course
she was talking electron flow and i was talking hole flow. we both got the
same result but the notation was all different.

That's not true at all Dave. Most of us know that current is current.
It really only flows one direction at any instant of time. We can
indeed consider systems as having current that flows two directions at
one instant of time, but the results of that better agree with the
actual real current that flows only in one direction at any instant of
time or they are wrong.

Also, behavior of basic components cannot change. A two terminal device
like a loading coil cannot have differences in the current flowing
through it at each terminal without a third path. (I assume we all
know current is not an across vector and it does not "drop", the person
who started this thread just used poor wording.)

I think the basic problem is Cecil wants to used some definition of
current that does not allow models to be freely exchanged and does not
produce results that match real world systems. It always has to match.
We can't have different results unless someone has an error.

The only reason I'm skimming the posts here and making the occasional
comment is I hate to see people trying to understand how this stuff
works be confused. The real fuss is a couple people seem to think
standing waves or "missing antenna length" are the root cause of
current being different in the two terminal component called a loading
coil.

It really isn't an argument or debate as much as trying to help lurkers
understand how the system really works, and not let them fall into the
trap that the loading coil behavior is any different than any other
coil, the only possible reason for differences in current at each
terminal is stray capacitance allowing displacement currents to the
outside world, and that any phase differences in current at each coil
terminal are also tied to capacitance from the coil to the world around
the coil.

It's not correct to assume people are talking about the same result
different ways, because both Cecil and Yuri have huge flaws in their
conclusions. They both seem to want the inductor to behave in some very
unique way just because it is an antenna, and the reults they seem to
claim do not match actual measurements. Cecil dismisses real
measurements with frantic arm waving about reflected and forward
current and no one being able to measure current and phase because of
standing waves, and while I think Yuri would accept measurements he
won't accept them when made by others and won't make them himself.

This has gone on for perhaps three years now. It is really up to Cecil
and Yuri to let it go, since they are the ones who seem to disagree
with measurements and accepted theory.

73 Tom

Dave wrote:
thats the basic problem in this whole discussion. you are all talking
about
the same thing, just using different notation and incomplete statements
so
that none of you understands exactly what the others are trying to talk
about... when really you are all saying the same thing. its kind of like
after i graduated from college with an ee degree and my sister graduated
from an air force basic electronics course, she tried to ask me something
about currents in a transistor and i saw it all backwards... well of
course
she was talking electron flow and i was talking hole flow. we both got
the
same result but the notation was all different.

That's not true at all Dave. Most of us know that current is current.
It really only flows one direction at any instant of time. We can
indeed consider systems as having current that flows two directions at
one instant of time, but the results of that better agree with the
actual real current that flows only in one direction at any instant of
time or they are wrong.

Also, behavior of basic components cannot change. A two terminal device
like a loading coil cannot have differences in the current flowing
through it at each terminal without a third path. (I assume we all
know current is not an across vector and it does not "drop", the person
who started this thread just used poor wording.)

ARGH! maybe it really is more basic than different notations and
terminology. when working with antennas and 'component's that are a
significant fraction of a wavelength in size you must take into account the
'third path'... the 'third path' consists of the distributed capacitance and
resistance that CAN be modeled with lumped components if you want to go
through all the approximations and extra calculations that are required. if
you are ignoring that 'path' when talking about relatively large loading
coils then you will be wrong, how wrong depends on how large of course.

i haven't been following all the different threads and junk in here, but if
you are trying to analyze a significant sized loading coil without taking
into account all the paths then you are going to likely be less accurate
than cecil using a more complete distributed model. OBVIOUSLY if you are
using a strict lumped model the current can't be different from one end to
the other. And just as obviously if you make a really large loading coil,
like a full '1/2 wave' slinky dipole, the current at the feedpoint end will
be MUCH different than at the open end. You can both get the same results,
but to do it with lumped elements requires the same calculations that are
done by finite element simulations that try to do enough small lumped
elements as possible to approximate the distributed equations that would
give nice smooth results. Unfortunately cecil does not do a good job in
relating the distributed model, and his constant references to 'optics' and
the use of terms related to that field do nothing but confuse many of the
people in here to think that he is in a different world. admit it cecil,
while you may be correct, using a different set of terminology than most of
the people in here has done nothing but add to the confusion factor in many
of this long drawn out threads.

I still think that if each of you explained the WHOLE problem in your own
terminology, INCLUDING all the assumptions that are required for the models
you are using, that you would find that each of you is correct. but because
you are starting from different sets of assumptions you will never find a
common ground.

enough of this, back to assembling my new linear loaded 40m beam... why
don't you go analyze that loading system for a while.

Dave wrote:
admit it cecil,
while you may be correct, using a different set of terminology than most of
the people in here has done nothing but add to the confusion factor in many
of this long drawn out threads.

I have a limited technical library. I wish my RF references spelled out
everything as well as "Optics", by Hecht, but mine don't. Light and RF
are the same kind of EM waves, just at different frequencies. Hecht's
material is certainly relevant to RF waves. And I make every effort to
translate the technical jargon from one field to the other as best I
know how.

Hecht presents the best treatment of superposition, interference,
and standing waves that I have ever seen. I wish I had an RF
reference book as well written as "Optics".
--
73, Cecil http://www.qsl.net/w5dxp

wrote:

I had this example at the bottom of my posting but you seem
to ignore such. So I am moving it to the top of the posting.
If you ignore it now, at least everyone will know you couldn't
possibly have missed it.

You are in a room with a 50 ohm transmission line routed
through a hole in one side of the room, across the room,
and through a hole in the other side of the room. You don't
know which is the source end of the line. A directional
wattmeter reads 200 watts forward power and 200 watts
reflected power but you don't know which direction is
forward. Here's a diagram:

200W-- 2 amps--
hole-------------------50 ohm coax-------------------hole
--200W --2 amps

Which direction is the standing wave current flowing?

If you knew forward current was moving left to right which
direction would the standing wave current be flowing?

That's not true at all Dave. Most of us know that current is current.

Too bad EZNEC disagrees with you as seen in the graphic at:

http://www.qsl.net/w5dxp/travstnd.GIF

The traveling wave current is virtually the opposite of the
standing wave current as can be seen by their different
equations. There is no phase information in the standing
wave current phase. Yet that is exactly the phase W7EL
used to try to measure the delay/phase shift through a
coil.

DC current is different from AC current. That's why the
DC or AC designations are necessary. RF forward current
is different from RF standing wave current. That's why
the different designations are necessary.

It really only flows one direction at any instant of time.

Or not at all at a standing wave current node.
Too bad we are talking RMS values here which is what EZNEC
reports. I'll ask the question of you: If one amp of RF
current is flowing in one direction and one amp of RF
current is flowing in the opposite direction, which direction
does the phasor sum of those two currents flow?

We can
indeed consider systems as having current that flows two directions at
one instant of time, but the results of that better agree with the
actual real current that flows only in one direction at any instant of
time or they are wrong.

The phase of standing wave current is unchanging. It doesn't "flow"
in the commonly accepted sense of the word. As Hecht says in "Optics":

"This is the equation for a STANDING or STATIONARY WAVE, as opposed
to a traveling wave. Its profile does not move through space; it is
clearly not of the form Func(x +/- vt)."

[Standing wave phase] "doesn't rotate at all, and the resultant
wave it represents doesn't progress through space - its a standing
wave."

If standing wave light doesn't move through space, then standing
wave RF also doesn't move through a wire.

(I assume we all
know current ... does not "drop", ...)

EM current does indeed drop exactly like EM voltage drops both
according to the attenuation factor. Just one more proof that
EM waves are not lumped circuit currents. The only difference
in the equation for transmission line voltage and current is
the voltage gets divided by the characteristic impedance which
is usually a resistive constant.

I think the basic problem is Cecil wants to used some definition of
current that does not allow models to be freely exchanged and does not
produce results that match real world systems. It always has to match.
We can't have different results unless someone has an error.

Exactly correct and the reason for the different results is your
error. In any conflict between the distributed network model and
the lumped circuit model, the distributed network model wins
every time since it is a superset of the lumped circuit model.

This has gone on for perhaps three years now. It is really up to Cecil
and Yuri to let it go, since they are the ones who seem to disagree
with measurements and accepted theory.

On the contrary, it is up to you and others to correct your
misconceptions about standing wave current. Your "accepted
theory" has holes in it that I could drive my GMC pickup
through.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
(snip)
You are in a room with a 50 ohm transmission line routed
through a hole in one side of the room, across the room,
and through a hole in the other side of the room. You don't
know which is the source end of the line. A directional
wattmeter reads 200 watts forward power and 200 watts
reflected power but you don't know which direction is
forward. Here's a diagram:

200W-- 2 amps--
hole-------------------50 ohm coax-------------------hole
--200W --2 amps

Which direction is the standing wave current flowing?

Lets also say that the wavelength of the waves passing through this
transmission line are as long as the room is wide (one wavelength fits
inside the room.

Then we can say that at any moment when the instantaneous magnitude of
he current is not at zero (and it will pass through zero all along the
line simultaneously, right?), the current will going in one direction
in half of that length *with varying magnitude) and the other way in
the other half (also with varying magnitude). I am not saying that
the direction reversal will necessarily be at the center, but that is
one possibility.

For example, if we took a snapshot of the current, all along the line
at the moment it peaked it might look like thislength of arrow
represents current magnitude, and head shows direction)(view in fixed
width font)

.....--- --- -- - - -- --- --- -- - - --......
hole-------------------50 ohm coax-------------------hole

This is a snapshot of the current all along the line at an instant.

A quarter cycle later, the current would be zero, everywhere.

A half cycle later (than the first snapshot) it would look like this:

.....--- --- -- - - -- --- --- -- - - --......
hole-------------------50 ohm coax-------------------hole

This is the pattern the standing wave function describes. The current
at every point has one of two phases, which are 180 degrees from each
other.

Is this how you see it?

John Popelish wrote:
This is the pattern the standing wave function describes. The current
at every point has one of two phases, which are 180 degrees from each
other.

Is this how you see it?

Yes, now which direction is that current flowing? If the
source were known to be to the left, would that change
your answer?
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
John Popelish wrote:

This is the pattern the standing wave function describes. The current
at every point has one of two phases, which are 180 degrees from each
other.

Is this how you see it?

Yes, now which direction is that current flowing?

You deleted the arrows which I drew that showed one possible case. Do
you have some argument with what you deleted?
(I'll replace it, so you don't have to go back to look at it)
(begin paste)

For example, if we took a snapshot of the current, all along the line
at the moment it peaked it might look like thislength of arrow
represents current magnitude, and head shows direction)(view in fixed
width font)

.....--- --- -- - - -- --- --- -- - - --......
hole-------------------50 ohm coax-------------------hole

This is a snapshot of the current all along the line at an instant.

A quarter cycle later, the current would be zero, everywhere.

A half cycle later (than the first snapshot) it would look like this:

.....--- --- -- - - -- --- --- -- - - --......
hole-------------------50 ohm coax-------------------hole
(end paste)

See all those arrows of various length representing current direction
and magnitude? Why do you ask me about something after erasing my answer?

If the source were known to be to the left, would that change
your answer?

For a pure standing wave, there is effectively a source at each end,
so this question is meaningless.