Loading Coils; was : Vincent antenna
 

Keith Dysart wrote:
These 90 degrees that Cecil insists are "always"
present are quite difficult to locate.

For anyone who knows how to use a Smith Chart,
those degrees are quite easy to locate.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Tom Donaly wrote:
Cecil Moore wrote:
Tom Donaly wrote:
Yes, but not using it very well, or you would have been
able to answer the math problem I posed to you.

I'm sorry, Tom, I didn't even read the math problem
you posed to me as I don't have time for it right
now. I'm sure anyone could use the distributed
network model to solve your problem, even you.

Never mind.

If you really think you have invented an example for
which the distributed network model will give erroneous
results, you really should present it.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
I believe you said you saw about a 7% shift between the two inputs to
your scope.

I don't recall saying anything like that. I don't even
know what that means. 7% of what?

Sorry, English is not my native language this month. I must have
misinterpreted the following message sent by you (11/30/2007, 3:35 pm).

I've described it before. I used a dual-trace
100 MHz O-scope and estimated the phase angle
between the two traces at about 7% of a cycle.

Sorry, I obviously made an error. It should have
been about 10% of a cycle.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:

Please fire up EZNEC and tell us how much current phase
shift is reported for 45 degrees of a 1/2WL dipole.

Can anyone point me to any reference to "standing-wave current" in any
reputable text?

"Transmission Lines", by Chipman, Chapter 8

A periodic waveform with no phase information? Huh?

Yes!!! Here's what Chipman says on page 159: "V(d)=A*cos(Bd).
This expression indicates that in the voltage standing wave
pattern produced on a lossless transmission line by a voltage
reflection coefficient, rho, at the terminal load end, the
*phase is constant over any half wavelength* of the pattern
between successive points of zero voltage magnitude, ..."

The same is true for the current standing wave pattern on
a standing-wave antenna and means that constant phase current
cannot be used for delay measurements.

"PHASE IS CONSTANT OVER ANY HALF WAVELENGTH" including the
part where the coil is located.

Please look at the phase of the current in a 1/2WL dipole
and tell us how to use phase measurements of that current
to determine the delay through the 1/2WL dipole wire.

There's no mystery about traveling or standing waves ...

Roy, please explain the phase shift reported by EZNEC for:

http://www.w5dxp.com/coil512.ez

Use the "Load Dat" button to view the phase shift.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

AI4QJ wrote:
Roy, this is the part I don't understand about some people posting on this
thread. A standing wave does *not* have a phase shift.

Robert A. Chipman agrees with you. He says the standing
wave phase is "... constant over any half wavelength ..."

Kraus also agrees. Here is a graphic from Kraus' book,
"Antennas", showing the lack of phase shift over the length
of a 1/2WL dipole. Essentially the same thing would be true
for short loaded dipoles and loaded mobile antennas.

http://www.w5dxp.com/krausdip.jpg

Roy admitted some time ago that EZNEC reports that
same constant phase for current over the entire length
of a 1/2WL dipole yet he still insists that same current
can be used to measure phase-shift/delay through a coil
when it cannot even be used to measure the phase shift
through 1/2WL of wire.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
Can anyone point me to any reference to "standing-wave current" in any
reputable text?

Will Kraus do? Here's a graphic from his book, "Antennas".
Please look at the phase of the current over the entire
1/2WL dipole. EZNEC and Chipman agree with Kraus.

http://www.w5dxp.com/krausdip.jpg
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

AI4QJ wrote:

Roy, this is the part I don't understand about some people posting on this
thread. A standing wave does *not* have a phase shift. The standing wave
stays in a single position and oscillates. The forward and reflected waves
are traveling. An excellent conceptualization of we mean by "standing wave"
with its constructive and destructive interference can be seen he

http://www.chemmybear.com/standing.html

My only problem is, you are the antenna software design guru. I know I must
be missing something big here because I would expect you to be telling
"others" this stuff.

You've described a standing wave, but haven't defined any special kind
of current known as "standing wave current". A standing wave isn't a
current, it's the shape of the magnitude of the voltage or current as a
function of position. I'm sure you can find multiple descriptions of
this on the web, with some being correct and well done, some being
totally wrong, and others at all points between. I tend to look to
published texts for accurate information, and currently have about 14
reputable texts involving transmission lines and electromagnetic waves
on my bookshelf. I surely might have missed it, but I don't recall ever
seeing a reference to "standing wave current" in any of them.

The nature of a standing wave is well known. It describes the envelope
of the distribution of voltage or current on a transmission line
resulting from the sum of forward and reverse traveling waves along a
line not terminated in its characteristic impedance. This envelope,
which has a physical periodicity along the line and which is sinusoidal
in shape only if the SWR is infinite, appears to stand still except for
increasing and decreasing in amplitude at the same rate as the traveling
waves which cause it. So "standing wave current" translates to "envelope
of an interference pattern current". There is no special kind of current
known as "standing wave current" because the combination of words is
meaningless.

Traveling waves interfere to cause the standing wave envelope, as I hope
your web references tell you. When you measure the current at some point
in a transmission line, you're measuring the current at that point,
period. Not "traveling wave current" or some other special kind of
current. The current at any point along a transmission line has a
magnitude and a phase relative to an arbitrary reference. Both can be
easily calculated from basic transmission line principles. You can do it
directly or by adding forward and reflected waves to get the total -- if
you get different results by using the two methods, you've done
something wrong.

For the record, I measured some currents in a wire on both sides of an
inductor at the base of an antenna a couple of years ago and posted the
results here. One of the things I measured, with some care, was the
phase angle between those currents. I didn't "mistakenly" measure
"standing wave current". There is no such thing. I measured sinusoidal
currents, which have phase and magnitude, at two points. The
measurements agreed quite closely with results predicted from
conventional theory. I never was able to tell whether they agreed with
Cecil's theory because he kept changing his predictions.

Note the assertion on the graphic that two waves can be at the same place at
the same time (a subject of a different thread), something I agree with :-)

You'll have to run that one by Cecil. He's said many times that
traveling waves bounce off each other when they meet. That behavior
seems to be necessary to support one of this theories.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

AI4QJ wrote:
Roy, this is the part I don't understand about some people posting on this
thread. A standing wave does *not* have a phase shift.

Gene said the same thing many months ago:

Gene Fuller, W4SZ wrote:
In a standing wave antenna problem, such as the one you describe,
there is no remaining phase information. Any specific phase
characteristics of the traveling waves died out when the startup
transients died out.

Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be
seen again.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

AI4QJ wrote:
"Roy Lewallen" wrote in message
...
Or why "virtually no phase information" exists in it. A periodic waveform
with no phase information? Huh?


Or do you mean that the amplitude of the standing wave does contain phase
information about phase 2 other waves, the forward and reflected waves,
relative to each other? Is that what you are saying (making this a semantic
issue again)? The standing wave itself is at zero phase angle.

Hopefully my other posting has mostly answered this.

The total current is the sum of forward and reflected waves. The
magnitude of this total has a periodic distribution, or envelope, alsong
the length of the line known as a standing wave. You can learn certain
things about the line and load by looking at the magnitude and position
of this envelope. The position of the envelope can very reasonably be
termed its "phase", although like the envelope making up the "wave",
it's a positional phase rather than a time related one. But neither the
amplitude nor the "phase" of the envelope known as the standing wave
will, by itself, tell you anything about the phase of the current at any
point along the line.

Confusion among the wave-like envelope of the standing wave, moving
traveling waves, positional and time related phase, and other
potentially ambiguous terms has been instrumental in sustaining
confusion about issues that aren't really very complicated.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
You've described a standing wave, but haven't defined any special kind
of current known as "standing wave current".

"Standing wave current" is the current that exists in standing-
wave antennas and stubs. It's phase is constant and cannot
be used to measure phase-shift/delay. EZNEC agrees.

Here is Kraus' graph of standing wave current.

http://www.w5dxp.com/krausdip.jpg

This is a graph of the currents you used for your measurements.
Note the virtually unchanging phase.

For the record, I measured some currents in a wire on both sides of an
inductor at the base of an antenna a couple of years ago and posted the
results here. One of the things I measured, with some care, was the
phase angle between those currents. I didn't "mistakenly" measure
"standing wave current".

EZNEC says that the phase angles of the currents you measured
are unchanging. An unchanging phase is useless for measuring
phase shifts.

You'll have to run that one by Cecil. He's said many times that
traveling waves bounce off each other when they meet.

That's just part of your Big Lie. Traveling waves
superpose. They do NOT "bounce off each other".
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
But neither the
amplitude nor the "phase" of the envelope known as the standing wave
will, by itself, tell you anything about the phase of the current at any
point along the line.

Yet, that is exactly the current you used for your
coil phase-shift measurements. Your position is
contradictory and indefensible.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Earlier, I had written:
"Likewise there are no glitches in the standard circuit models for
inductance and capacitance. They work just fine, for all cases where the
dimensions of the circuit are very small with respect to the wavelength,
so that distributed effects and radiation are negligible. Where those
assumptions are no longer accurate, we can extend the simple model to
include some corrections. But the most important point is, we always
know that we're building up from a solid foundation."

Cecil Moore wrote:
Ian White GM3SEK wrote:
Cecil Moore wrote:
Ian White GM3SEK wrote:
Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Really???? Just try your lumped inductance model on
a helical antenna and get back to us.
Yet more stinking dishonest quoting from Cecil. What I ACTUALLY
wrote was:
"Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Yep, that's exactly as I quoted it.

Once could have been a mistake. Twice is deliberate, dishonest
manipulation.

The beauty of Usenet is that it's now on permanent record.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Loading Coils; was : Vincent antenna
 

On Sat, 8 Dec 2007 22:58:42 -0500, "AI4QJ" wrote:

Remember, the system was *measured* to be 1/4W so the reflections must cause
a short every 125 nsec, no matter what is happening in between.

Hi Dan,

Keith was quite specific to separate the transient state from the
steady state such that a short is not available "every 125 nS." Most
125 nS, perhaps, but not initially and so not "every 125 nS." Trivial
distinction on the face of it, perhaps. When paired up with an
absolute statement that has been "proven" to be universally true, then
trivial is enough to sink the Titanic.

The smith chart and
phaser diagrams should work and are equivalent to using math.

There are two solutions: transient and steady states; there are two
maths. Cecil, in the same breath, manages to jump from one to the
other enough that you should be acquainted with both by now - or you
will be when you suddenly find yourself facing a paradox: Like why is
the band that is playing "Nearer, My God, to Thee" is at such an odd
sloping angle on the boat deck?

Fortunately it takes only a little effort to follow one line, and to
drill down to an absurdity. His proving Tom's delay was no better
than his own measurement demonstrated this easily. The drilling down
was in simply noting the particulars and skipping all the fluff of
trivial sidebars. Most folks find the fluff attractive and chase it
to no conclusion instead (that is how this thread accumulated 600
postings).

Keith, on the other hand, has the discipline to simply stick to one
issue, and drill down. Patience brings rewards in the end.

73's
Richard Clark, KB7QHC

Loading Coils; was : Vincent antenna
 

Ian White GM3SEK wrote:
... Where those
assumptions are no longer accurate, we can extend the simple model to
include some corrections. But the most important point is, we always
know that we're building up from a solid foundation."
...

In the profession which puts meat on my table, that/those are called
"magic numbers" and are a sure sign something is amiss, either with the
understanding of the problem(s), the methods or the person attempting
the solutions ...

Regards,
JS

Loading Coils; was : Vincent antenna
 

On Sat, 8 Dec 2007 23:59:56 -0500, "AI4QJ" wrote:

standing wave currents

Hi Dan,

When these three keywords are braced with quotes, Google reveals all
of 19, non-duplicated sources. Not a very compelling testimony to
this phrase's usage when the phrase "current standing wave" results in
at least 10 times that amount. Even more so, neither amount to many
references.

When googling the separate term Current from the phrase "standing
wave;" then the hits count climbs through the ceiling to nearly
200,000 links or 1000 to 10000 times the unique phrases above.

Simple deconstruction would suggest that
standing wave currents
is about as useful as downloading a windows patch from
www.micorsoft.com. Would you? (Try the link and see if you would
trust the source.)

Deconstruction aside, what I see missing in your enquiry into this
"current" is any question about what information it contains. I've
seen the suggestion of phase, and Roy has answered that, but in
isolation (no reference) there is magnitude only. Cecil's
reconstructed, but revisionist measurement that disputes Tom's data
published on the web; it was nearly identical to Tom's when phases
were reconciled in his test arrangement.

Even here in the post you've responded to, Roy demonstrated the
normalization of scope channel's separate delays. Given it was his
trade for umpteen years in their design (as it was my trade to
calibrate them), and Cecil's trade was building flip flops (the only
phase there is 180 degrees and nothing in between); then who has a
better grasp on the fundamentals? An IQ of 260 doesn't mean anyone is
educated or has a skill.

73's
Richard Clark, KB7QHC

Loading Coils; was : Vincent antenna
 

I think it might be useful to say a little more about standing waves.

Imagine a single lossless transmission line with a sine wave source at
one end and a load at the other. Begin with a load equal to the line's
Z0. Make a graph of the magnitude of the current or voltage as a
function of distance from the source. With the Z0 load, the magnitude
will be the same all along the line so your graph will be a straight
line. This is a "flat" line, with no standing wave. A probe sitting at
one spot would show the instantaneous voltage or current amplitude going
up and down in a sinusoidal manner. A probe a bit farther down the line
would look the same, but delayed; there's a phase difference between the
voltages or currents at the two points. The phase difference is equal to
the line's physical length in degrees divided by the velocity factor.

Now change the load so the line is slightly mismatched. A standing wave
will appear -- the graph of amplitude vs distance won't be flat any
longer, but will have a ripple added to its previous constant value.
(The VSWR is, by definition, the ratio of the highest to the lowest
values of the voltage envelope on a line long enough to have a full
maximum and minimum. The current SWR is the same.) The maxima and minima
of the ripple don't move, hence the name "standing wave". If we look at
the instantaneous voltage or current at a single point, it will go up
and down in step with the source as before. If we also look at the
second point, it'll also go up and down as before, and there will be a
phase angle between the two. But there are two interesting differences
from the flat line: One is that the amplitudes at the two points are now
unequal unless they're an integral number of half electrical wavelengths
apart (or a few other special cases). The other is that the phase shift
isn't the same as before. There's still a phase shift between the two
points, but it's no longer equal to the electrical length of the line
between the points. We'll find that either the voltage has shifted more
and the current less, or vice versa depending on the load and which
points we've chosen. But at every point the current and voltage still
have phase angles which change with position along the line. That is to
say, the voltage or current at one point is delayed compared to the
voltage or current at the other.

As the mismatch gets more extreme (i.e., the SWR increases), the
magnitudes at the two points get more different, and the phase deviates
farther from the electrical length of line between them. (This is why
you can't expect phased array "delay lines" to provide a delay equal to
the lines' electrical lengths when they're not terminated with Z0.)

At the most extreme case of mismatch -- an open, short, or purely
reactive load, resulting in an infinite SWR -- the amplitude of the
standing wave along the line goes from zero to twice the value it had
when the line was flat. And a really interesting thing happens to the
phase of the voltages and currents on the line. Remember how as the
mismatch got worse, the voltage and current phase difference between two
points got farther and farther away from the electrical line length
between them? Well, when the SWR is infinite, it's gotten to the point
where the voltage or current phase remains the same for a distance of a
half electrical wavelength, then abruptly changes 180 degrees, repeating
every half electrical wavelength. Some antennas behave in some (and only
some) ways like transmission lines, and you'll find that modeling
programs report just this behavior of the phase of the current along a
straight wire antenna.

The standing wave and all the characteristics of the voltage and current
(e.g., how their magnitude and phase varies with position along the
line) follow directly from an analysis of forward and reflected
traveling waves on the line. The voltage or current at any point is
simply the sum of the two waves at that point, and they have the
properties I've just described.

I hope this helps in clarifying the meanings of traveling and standing
waves, voltage and current along a transmission line. I'm sure there are
lots of good graphical illustrations available -- but some bad ones too.
Hopefully keeping this explanation in mind when you look at the nice
graphics displays will help you sort the bad ones from the good.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

On Dec 8, 10:58 pm, "AI4QJ" wrote:
"Keith Dysart" wrote in message
On Dec 8, 3:15 pm, "AI4QJ" wrote:
In this example, we have transmission lines, not an antenna or antenna
coil.
The total phase shift is 90 degrees or 62.5 nsec.

Only with great stretching.

The 10 degree 100 ohm line contributes 6.94nsec,

Correct.

the 43 degree 600 ohm line contributes 29.86 nsec.

Correct.

But now think in the time domain for a bit.
29.86 nsec after the signal is first applied it reaches the
discontinuity. 29.86 nsec later the first reflection arrives
back at the start. 13.8 nsec later the first reflection from
the end of the 100 ohm section arrives back at the start.
It takes many more reflections of reflections before the
impedance at the input starts to look like a short.

Nowhere in here will you be able to find anything that
happens in 62.5 nsec.

The key point is that since 62.5 nsec represents 1/4WL at the
frequency of interest, if the line was 1/4WL long, you would
find things that happen every 62.5 nsec.

The values returned back to the feed point are superimposed
in the time domain, adding and subtracting, but the whole system should
(*does*) still act like a 1/4W stub at 4MHz.

There is no doubt that all the variants discussed do share one
property with a 1/4WL open stub; the input impedance after a
long settling time is the same. But other properties, particularly
settling time, are quite different.

A 1/4W stub could consist of
1..N series transmission lines of different impedances provided they were
cut to the correct lengths.

Quite true. And if your definition of 14WL stub was anything that
produced a short, I would agree that it is self-consistent
but that it is probably not too useful.

Remember, the system was *measured* to be 1/4W so the reflections
must cause a short every 125 nsec, no matter what is happening in between.

If I understand what your are saying, then NO. Consider the short
itself.
There is no delay what-so-ever.

If you are saying that along the transmission line there is a point
every 125 nsec where the impedance is 0, I would agree for
a constant impedance line, but if you change the impedance then
the points on either side of the discontinuity are not 125 nsec
apart.

The task is to use the math to verify the measurement. The smith chart and
phaser diagrams should work and are equivalent to using math. Time domain is
possible too but no way I would ever go to that trouble on usenet at least!
Or do you think the measurement was wrong?-

I have no disagreement with the resulting numbers.

But 46.4 + 10 does not equal 90. Subtracting (46.4 + 10)
from 90 does not yield a useful number, though if you
decide that the sum MUST be 90 for some reason, then
you do have the number that will do that.

....Keith

Loading Coils; was : Vincent antenna
 

Ian White GM3SEK wrote:
Once could have been a mistake. Twice is deliberate, dishonest
manipulation.

Absolutely nothing dishonest about it.

Once you make a mistake, Ian, it doesn't matter what
you say after the mistake. What I disagreed with was
your mistake and didn't bother quoting the rest. I
believe that is part of the netnews guidelines.

So I challenge you again. Given a two wavelength
slinky dipole, please use your lumped constant
model to predict the current in the antenna.

Of course, you cannot and will not do that.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
His proving Tom's delay was no better
than his own measurement demonstrated this easily.

Here's your logic, Richard. You ask me how much
is two plus two. I don't respond. Your conclusion
is that I don't know how much is two plus two.
The truth is that I simply tired of your nonsense.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Ian White GM3SEK wrote:
Cecil Moore wrote:
Yep, that's exactly as I quoted it.

Once could have been a mistake. Twice is deliberate, dishonest
manipulation.

Ian, your first sentence was false and I responded to it.
No amount of words that you post after the first false
statement will make it true. There *are* glitches in the
standard circuit models for inductance and capacitance
because they do not agree with Maxwell's equations.
There was nothing dishonest about my replies. In fact,
I was just following netnews rules.

You said:
Likewise there are no glitches in the standard circuit
models for inductance and capacitance.

But there are glitches in that model so that is a false
statement to which I replied. Nothing you can say after
that statement will make it true.

I am sorry that you get so upset when challenged but
you are wrong about a lot of things.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
"AI4QJ" wrote:
standing wave currents

When these three keywords are braced with quotes, Google reveals all
of 19, non-duplicated sources.

When the keywords, "current in standing waves", is used
Google comes up with 294,000 hits.

Cecil's
reconstructed, but revisionist measurement that disputes Tom's data
published on the web; it was nearly identical to Tom's when phases
were reconciled in his test arrangement.

This is absolutely not true. One wonders what you have
to gain by falsifying technical data. One wonders why
you have not responded to my request to explain the
"Load Dat" results of http://www.w5dxp.com/coil512.ex
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
I think it might be useful to say a little more about standing waves.

Imagine a single lossless transmission line with a sine wave source at
one end and a load at the other. Begin with a load equal to the line's
Z0. Make a graph of the magnitude of the current or voltage as a
function of distance from the source. With the Z0 load, the magnitude
will be the same all along the line so your graph will be a straight
line. This is a "flat" line, with no standing wave. A probe sitting at
one spot would show the instantaneous voltage or current amplitude going
up and down in a sinusoidal manner. A probe a bit farther down the line
would look the same, but delayed; there's a phase difference between the
voltages or currents at the two points. The phase difference is equal to
the line's physical length in degrees divided by the velocity factor.

I've done exactly that with current using EZNEC. The traveling wave
graph is on the left at http://www.w5dxp.com/travstnd.gif

The standing wave current graph described in Roy's next quoted
paragraph below is on the right. The tabulated data provided by
EZNEC is at the bottom.

If standing-wave current is all that exists, EZNEC faithfully
reports the amplitude and phase of the standing-wave current.

If traveling-wave current is all that exists, EZNEC faithfully
reports the amplitude and phase of the traveling-wave current.

At the most extreme case of mismatch -- an open, short, or purely
reactive load, resulting in an infinite SWR -- the amplitude of the
standing wave along the line goes from zero to twice the value it had
when the line was flat. And a really interesting thing happens to the
phase of the voltages and currents on the line. Remember how as the
mismatch got worse, the voltage and current phase difference between two
points got farther and farther away from the electrical line length
between them? Well, when the SWR is infinite, it's gotten to the point
where the voltage or current phase remains the same for a distance of a
half electrical wavelength, then abruptly changes 180 degrees, repeating
every half electrical wavelength. Some antennas behave in some (and only
some) ways like transmission lines, and you'll find that modeling
programs report just this behavior of the phase of the current along a
straight wire antenna.

The question is, Roy, since as you say, "the current phase remains
the same for a distance of a half electrical wavelength", how can
you possibly use that same current to measure the phase shift
through a coil and convert your reading to a delay through the
coil? If the phase of the current doesn't change over the entire
1/2 wavelength, it certainly doesn't change through the coil. What
you have proven above is that your and W8JI's previously reported
coil measurements are meaningless and that the only valid way to
measure the delay through a coil is to use the traveling wave
current described in your first paragraph above.

What you are saying in the above paragraph is that the current in
a high-SWR environment carries virtually no phase information. So
the question remains:

WHY DO YOU THINK THAT PHASE MEASUREMENTS OF STANDING WAVE CURRENT,
GIVEN ITS VIRTUALLY UNCHANGING PHASE, WILL YIELD ANY USEFUL
INFORMATION ABOUT THE DELAY THROUGH A LOADING COIL?

You did measure the phase shift through the coil but the
measurement was meaningless and the conclusions invalid.
We already knew it would be close to zero and bear no
relationship to the delay through the loading coil -
BECAUSE THERE IS VIRTUALLY NO PHASE INFORMATION IN THE
PHASE OF STANDING WAVES.

The phase information in standing waves is in the amplitude
but you obviously don't realize that fact since you continue
to talk about the current "drop" through the coil being due
to losses, radiation, and leakage to the environment. If there
were zero losses, zero radiation, and zero leakage, the current
"drop" would still be there as a result of nothing more than
the superposition of the forward and reflected waves.

I hope this helps in clarifying the meanings of traveling and standing
waves, voltage and current along a transmission line.

I agree with what you have said in this posting. Unfortunately
for you, what you said in this posting contradicts and invalidates
the conclusions that you and W8JI drew from your phase
measurements of current through a loading coil in a standing-
wave antenna.

Out of one side of you mouth, you tell us that the standing-
wave current phase is unchanging over 1/2 wavelength. Out of
the other side of you mouth, you tell us that same current can
be used to measure the delay through a loading coil. Please
pick one side or the other - they cannot both be right.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:

Ian, I apologize for yanking your chain. It is a bad
habit of mine.

Ian White GM3SEK wrote:
Cecil Moore wrote:
Yep, that's exactly as I quoted it.

Once could have been a mistake. Twice is deliberate, dishonest
manipulation.

Ian, your first sentence was false and I responded to it.
No amount of words that you post after the first false
statement will make it true. There *are* glitches in the
standard circuit models for inductance and capacitance
because they do not agree with Maxwell's equations.
There was nothing dishonest about my replies. In fact,
I was just following netnews rules.

Continuing: If your model worked, W8JI would not have
measured a 3ns delay on 4 MHz through a 2" dia, 100 T,
10" long coil. It is, in fact, your flawed model that
allowed him to come to the false conclusions that he
did. And I notice your model got you in trouble because
you did not offer one word of objection to his obviously
impossible conclusions.

You guys are religiously addicted to models that do
not correspond to reality and it gets you into a lot
of trouble including passing false information along
to your naive readers.

It appears that we are on the verge of proving that a
3 ns delay through the above coil is impossible no
matter what your model says.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Hi Roy,

Could I add this observation? Both traveling waves and standing waves
can be measured. A single volt meter or ammeter will measure the
standing wave which is the sum of the traveling waves.. A DIRECTIONAL
volt meter or ammeter will measure only the traveling wave within the
design direction, but can not distinguish between components from
multiple reflections that might combine.

A directional voltmeter or ammeter will measure the same voltage or
current no matter where it is placed in the transmission line under
steady state conditions, assuming no resistive losses in the
transmission line.

73, Roger, W7WKB

Roy Lewallen wrote:
I think it might be useful to say a little more about standing waves.

Imagine a single lossless transmission line with a sine wave source at
one end and a load at the other. Begin with a load equal to the line's
Z0. Make a graph of the magnitude of the current or voltage as a
function of distance from the source. With the Z0 load, the magnitude
will be the same all along the line so your graph will be a straight
line. This is a "flat" line, with no standing wave. A probe sitting at
one spot would show the instantaneous voltage or current amplitude
going up and down in a sinusoidal manner. A probe a bit farther down
the line would look the same, but delayed; there's a phase difference
between the voltages or currents at the two points. The phase
difference is equal to the line's physical length in degrees divided
by the velocity factor.

Now change the load so the line is slightly mismatched. A standing
wave will appear -- the graph of amplitude vs distance won't be flat
any longer, but will have a ripple added to its previous constant
value. (The VSWR is, by definition, the ratio of the highest to the
lowest values of the voltage envelope on a line long enough to have a
full maximum and minimum. The current SWR is the same.) The maxima and
minima of the ripple don't move, hence the name "standing wave". If we
look at the instantaneous voltage or current at a single point, it
will go up and down in step with the source as before. If we also look
at the second point, it'll also go up and down as before, and there
will be a phase angle between the two. But there are two interesting
differences from the flat line: One is that the amplitudes at the two
points are now unequal unless they're an integral number of half
electrical wavelengths apart (or a few other special cases). The other
is that the phase shift isn't the same as before. There's still a
phase shift between the two points, but it's no longer equal to the
electrical length of the line between the points. We'll find that
either the voltage has shifted more and the current less, or vice
versa depending on the load and which points we've chosen. But at
every point the current and voltage still have phase angles which
change with position along the line. That is to say, the voltage or
current at one point is delayed compared to the voltage or current at
the other.

As the mismatch gets more extreme (i.e., the SWR increases), the
magnitudes at the two points get more different, and the phase
deviates farther from the electrical length of line between them.
(This is why you can't expect phased array "delay lines" to provide a
delay equal to the lines' electrical lengths when they're not
terminated with Z0.)

At the most extreme case of mismatch -- an open, short, or purely
reactive load, resulting in an infinite SWR -- the amplitude of the
standing wave along the line goes from zero to twice the value it had
when the line was flat. And a really interesting thing happens to the
phase of the voltages and currents on the line. Remember how as the
mismatch got worse, the voltage and current phase difference between
two points got farther and farther away from the electrical line
length between them? Well, when the SWR is infinite, it's gotten to
the point where the voltage or current phase remains the same for a
distance of a half electrical wavelength, then abruptly changes 180
degrees, repeating every half electrical wavelength. Some antennas
behave in some (and only some) ways like transmission lines, and
you'll find that modeling programs report just this behavior of the
phase of the current along a straight wire antenna.

The standing wave and all the characteristics of the voltage and
current (e.g., how their magnitude and phase varies with position
along the line) follow directly from an analysis of forward and
reflected traveling waves on the line. The voltage or current at any
point is simply the sum of the two waves at that point, and they have
the properties I've just described.

I hope this helps in clarifying the meanings of traveling and standing
waves, voltage and current along a transmission line. I'm sure there
are lots of good graphical illustrations available -- but some bad
ones too. Hopefully keeping this explanation in mind when you look at
the nice graphics displays will help you sort the bad ones from the good.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
AI4QJ wrote:
Roy, this is the part I don't understand about some people posting on
this thread. A standing wave does *not* have a phase shift.

Gene said the same thing many months ago:

Gene Fuller, W4SZ wrote:
In a standing wave antenna problem, such as the one you describe,
there is no remaining phase information. Any specific phase
characteristics of the traveling waves died out when the startup
transients died out.

Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be
seen again.

Cecil,

As usual, you continue to take things out of context. That quote
specifically referred to the (kz-wt) "phase". Simple examination of the
ideal standing wave equation shows my quoted comment to be correct.

However, I have also pointed out on several occasions that there are
multiple definitions for phase. It is not necessary to have a (kz-wt)
term in order to have valid and useful "phase" in a circuit.

But you already know that.

73,
Gene
W4SZ

Loading Coils; was : Vincent antenna
 

On Sun, 09 Dec 2007 03:32:59 -0800, Roy Lewallen
wrote:

Hopefully keeping this explanation in mind when you look at the nice
graphics displays will help you sort the bad ones from the good.

Hi Roy,

Your description of the Phase and the SWR contribution to how it is
perceived was excellent; and with enough words to get from start to
finish and be thorough.

It deserves acknowledgement.

However, with this buried beneath all the trash of this thread, it
should be included in your own site's miscellaneous files for easier
reference, because the misperceptions for this topic (and Cecil
stepped right up to shove a stick in the spokes) just aren't going to
go away.

73's
Richard Clark, KB7QHC

Loading Coils; was : Vincent antenna
 

On Sun, 09 Dec 2007 14:40:43 GMT, Cecil Moore
wrote:

Cecil's
reconstructed, but revisionist measurement that disputes Tom's data
published on the web; it was nearly identical to Tom's when phases
were reconciled in his test arrangement.

This is absolutely not true.

This is merely the hysterical reaction to personal embarassment.

One wonders what you have
to gain by falsifying technical data.

The data was wholly of your own supply. As I pointed out, the obvious
conclusion you reject in my quote above could only be satisfied by
your impeaching your own data. ;-)

One wonders why
you have not responded to my request to explain the
"Load Dat" results of http://www.w5dxp.com/coil512.ex

"One" is the keyword and luckily it is only "one." If other's pressed
me, I might be motivated, but you don't have that capacity.

Count yourself lucky to have mooched the validation you have from the
few who haven't been around the block with you.

Loading Coils; was : Vincent antenna
 

On Sun, 09 Dec 2007 14:25:35 GMT, Cecil Moore
wrote:

Richard Clark wrote:
His proving Tom's delay was no better
than his own measurement demonstrated this easily.

Here's your logic, Richard. You ask me how much
is two plus two. I don't respond. Your conclusion
is that I don't know how much is two plus two.
The truth is that I simply tired of your nonsense.

All would agree we have conclusions that are both indisputable. ;-)

I hope others will observe these six lines, one exchange, exhibits the
classic low hanging fruit that can be gathered by simply drilling down
through them! It really is just that simple and Cecil always hands it
to me on a silver plate.

Loading Coils; was : Vincent antenna
 

Keith Dysart wrote:
The key point is that since 62.5 nsec represents 1/4WL at the
frequency of interest, if the line was 1/4WL long, you would
find things that happen every 62.5 nsec.

No, that is not a key point. If we figure out some way
to get a 90 degree phase shift to happen in 10 nsec, so
be it. There is nothing that forces a phase shift to
take the same amount of time as it does in a transmission
line.

There is no doubt that all the variants discussed do share one
property with a 1/4WL open stub; the input impedance after a
long settling time is the same. But other properties, particularly
settling time, are quite different.

I don't have a problem with that statement. Everything I
have talked about is in regards to steady-state conditions.

If you are saying that along the transmission line there is a point
every 125 nsec where the impedance is 0, I would agree for
a constant impedance line, but if you change the impedance then
the points on either side of the discontinuity are not 125 nsec
apart.

If I never said that, your statement would still be true.
I agree and never said otherwise.

But 46.4 + 10 does not equal 90.

Yet we know for certain that the reflected wave has undergone
a 90 degree phase shift or else it wouldn't be in phase with
the forward wave at the feedpoint. That additional phase shift
has no time constraint. Deduction will tell one where it is
located. It is not in the 600 ohm section. It is not in the
100 ohm section. It is not at the open end of the stub. Since
the only location left is the impedance discontinuity, it must
occur at that point and indeed the Smith Chart shows us that
is exactly where it occurs in an exactly predictable value.
"Elementary, my dear Watson".
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

On Sun, 09 Dec 2007 15:16:52 GMT, Cecil Moore
wrote:

If standing-wave current is all that exists, EZNEC faithfully
reports the amplitude and phase of the standing-wave current.

It would appear that our author has some doubt about the statement
above to have prefaced it with "if." A grammarian would point out
that there is no corresponding "then." As this doubt is obviously a
contorted product of tension, I won't look for spelling errors that
Cecil would expect me to find.

If traveling-wave current is all that exists, EZNEC faithfully
reports the amplitude and phase of the traveling-wave current.

Again, the same nagging doubt - "if" indeed.

We can summarily answer that doubt by immediately dismissing it. There
is no such thing as standing-wave or traveling-wave current. The
statements above with the doubting "if" stripped out would read:

The current found in the solution of the standing-wave is all that
exists, EZNEC faithfully reports the amplitude and phase of that
current.

The current found in the solution of the traveling-wave is all
that exists, EZNEC faithfully reports the amplitude and
phase of that current.

Again, drilling down yields another silver plate of low hanging fruit.

73's
Richard Clark, KB7QHC

Loading Coils; was : Vincent antenna
 

Roger wrote:
Could I add this observation? Both traveling waves and standing waves
can be measured. A single volt meter or ammeter will measure the
standing wave which is the sum of the traveling waves.. A DIRECTIONAL
volt meter or ammeter will measure only the traveling wave within the
design direction, but can not distinguish between components from
multiple reflections that might combine.

A directional voltmeter or ammeter will measure the same voltage or
current no matter where it is placed in the transmission line under
steady state conditions, assuming no resistive losses in the
transmission line.

Perhaps if Roy would have used a directional coupler to
measure the phase shift through his coil, he would have
realized his conceptual mistake a lot sooner. But his
current transducers have absolutely no directional
capabilities at all.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Gene Fuller wrote:
As usual, you continue to take things out of context. That quote
specifically referred to the (kz-wt) "phase". Simple examination of the
ideal standing wave equation shows my quoted comment to be correct.

I know and you know that when you posted those technical
facts, you thought they supported W7EL's side and contra-
dicted mine. Surprise! W7EL was the one making outrageous
assertions, not me. I know and you know that you wish you
could take those remarks back because they contradict W7EL
but they are now preserved on Google.

The technical facts will eventually win out even if it
hairlips every guru on this newsgroup.

However, I have also pointed out on several occasions that there are
multiple definitions for phase.

We are using the EZNEC convention for "phase". Other
definitions do not matter in this context.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
Hi Roy,
Your description of the Phase and the SWR contribution to how it is
perceived was excellent; and with enough words to get from start to
finish and be thorough.

It deserves acknowledgement.

Roy simply posted my arguments in minute detail. I agree
with it and point out that it also proves that Roy's and
Tom's phase measurements using standing-wave current were
meaningless as they did *NOT* measure the delay through a
coil as asserted by both parties.

Roy's posting is entirely correct. He correctly points
out the difference in traveling-wave current and standing-
wave current which can be deduced from their different
equations. From Roy's own posting, anyone can deduce why
standing-wave current cannot be used to measure the delay
through a coil, yet last time I checked, Roy was still
"standing by" those meaningless measurements and also
supporting W8JI's equally meaningless measurements.

Would anyone who cares send Roy an email asking him to
make up his mind? He simply cannot have it both ways.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
Cecil Moore wrote:
This is absolutely not true.

This is merely the hysterical reaction to personal embarassment.

No, it is the response to an unethical attack. You
cannot lie willy-nilly on this newsgroup, and get
away with it.

The data was wholly of your own supply.

The data was mine - the lies were yours. For anyone
well versed in diversions, your attempts to sweep
technical facts under the rug are more than obvious.
When you are exposed, what will you do then?
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
I hope others will observe these six lines, one exchange, exhibits the
classic low hanging fruit that can be gathered by simply drilling down
through them! It really is just that simple and Cecil always hands it
to me on a silver plate.

I am a simple person, Richard. What you see if what
you get. I don't need to expose you for what you are.
You do a better job of that than I could ever do.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
It would appear that our author has some doubt about the statement
above to have prefaced it with "if." A grammarian would point out
that there is no corresponding "then."

Be sure to pull the cover over that hole you are digging
for yourself since you will shortly be too embarrassed to
show your face in public. :-)

There
is no such thing as standing-wave or traveling-wave current.

Good grief, Richard, are you really willing to sacrifice
your technical integrity in support of your guru idols?
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

On Sun, 09 Dec 2007 14:51:17 -0600, Cecil Moore
wrote:

When you are exposed, what will you do then?

Probably take a leak. Oh! You must have something else in mind when
you use the word exposed. Do you have anything that would remove the
cloud from your obscure language?

Is your outrage merely the embarrassment of a failed suicide attempt
with your data wearing a dynamite vest to embrace Tom's? The last
step in making it a successful attempt is a painful admission that you
are both wrong! That conclusion is not so far away as to be false is
it? -faint heart n'er won fair argument- Pull the pin!

It's not like you have actually pointed to any specific datum that was
in error. It's not like you have provided us with any amplifying
details taken from your measurement that converges with Tom's. I've
seen no dispute about the numbers or the typical normalization of an
O'scope. My posting is exceptionally short and entirely based on your
own facts. Your objections would, of course, be solved with you
indicting your own evidence. Was it as bad as perjury? Did you
misread some settings? Were the current probes in the wrong place?
Was there the proximity of a large conductor that disturbed your
results? Did you plug-n-chug the wrong Xeroxed formula? What went
wrong? More importantly: why is it my fault?

Unfortunately, in the last 127 postings you have forever forsaken the
details of your measurement to oblivion and returned to the opiate of
synthetic solutions.

Noting the complete absence of technical substance to your
accusations, your leg must be getting wet by now. Is it raining down
your way? ;-)

Loading Coils; was : Vincent antenna
 

Ian White GM3SEK wrote:
Earlier, I had written:
"Likewise there are no glitches in the standard circuit models for
inductance and capacitance. They work just fine, for all cases where the
dimensions of the circuit are very small with respect to the wavelength,
so that distributed effects and radiation are negligible. Where those
assumptions are no longer accurate, we can extend the simple model to
include some corrections. But the most important point is, we always
know that we're building up from a solid foundation."

Cecil Moore wrote:
Ian White GM3SEK wrote:
Cecil Moore wrote:
Ian White GM3SEK wrote:
Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Really???? Just try your lumped inductance model on
a helical antenna and get back to us.
Yet more stinking dishonest quoting from Cecil. What I ACTUALLY
wrote was:
"Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Yep, that's exactly as I quoted it.

Once could have been a mistake. Twice is deliberate, dishonest
manipulation.

The beauty of Usenet is that it's now on permanent record.



He's trying the old if-I'm-unreasonable-enough-I-can-get-him-to-quit-
posting routine. In other words, he's hoping you'll give up in anger.
I think it's about time to boycott Cecil - and his Sancho Panzas -
again. He makes no more sense than he ever did, and arguing with him
is a waste of energy anyway.
73,
Tom Donaly, KA6RUH

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
It's not like you have actually pointed to any specific datum that was
in error.

If you believe that, you have your blinders on, which
any rational person already knew. A 3 ns delay through
a 2" dia, 100T, 10" coil at 4 MHz is impossible!!! Is
that specific enough for you?

Unfortunately, in the last 127 postings ...

You are responsible for half of those. I predicted
that you were going to complain about my number of
postings engineered by you and I was right.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

AI4QJ wrote:
Thank you for you detailed responses and I think we completely agree once we
have agreement in our definitions.

But do you agree that standing-wave current phase can
be used to measure the delay through a loading coil?
--
73, Cecil http://www.w5dxp.com