Cecil Moore wrote:
John Popelish wrote:

It seems that this is nearly what you are demonstrating with your
EZNEC examples. Electrical length (propagation distance) is
collapsing into the inductor.


Please explain how that could be possible with constant
magnitude and phase of the currents through the coil.
The magnitude and phase is absolutely constant according
to the presuppositions of the lumped-circuit model. How
could it possibly collapse?

Have I claimed that the lumped model strictly applies? ;-)

Tom Ring wrote:
Picking a nice round number, say 55 degrees, I would then need 35
degrees of whip above that coil to make a quarter wave resonant antenna,
correct?

No, that is a myth spread by some people as a strawman
argument. Please don't support that strawman.

The requirement for resonance at the feedpoint is that
the phasor sum of the forward and reflected voltages
be in phase with the phasor sum of the forward and
reflected currents. Therefore, 90 degrees is *NOT*
required in the round trip. Indeed, the round trip
for the voltage doesn't have to be the same number
of degrees as the round trip for the current. That is
a misconception spawned by the lumped-circuit model
where everything is perfect and waves travel faster
than the speed of light. The real world is not so
perfect.

Given that the resonant feedpoint impedance equals
(Vfor+Vref)/(Ifor+Iref) isn't it obvious that the
individual components are not required to have the
same phase? For instance, Vfor could be at +50 degrees,
Vref could be at -40 degrees, Ifor could be at +20
degrees, Iref could be at -10 degrees, and the feedpoint
impedance would still be resistive.

The coil distorts the heck out of the phase relationships
between the voltages and the currents. Why is it surprising
that the result is unpredictable and needs an antenna
analyzer to find the resonant frequency? Factor in that
the lowest 50 ohm SWR may not be at the purely resistive
point and what do you have?
--
73, Cecil http://www.qsl.net/w5dxp

John Popelish wrote:
It looks like various magnitudes that you would find at 2 points along a
standing wave, with various fractions of the wave in the inductor as
frequency changes. In spite of hitting these various magnitude values,
there are still only two phases, 0 or 180 anywhere outside the coil. In
some cases, the standing wave goes through a node, inside the coil and
reverses phase from one end of the coil to the other.

Exactly! Now please explain how the nS delay through a coil
could possibly be measured using a signal that abruptly shifts
fixed phase by 180 degrees every 180 degrees.
--
73, Cecil http://www.qsl.net/w5dxp

John Popelish wrote:

Cecil Moore wrote:
Please explain how that could be possible with constant
magnitude and phase of the currents through the coil.
The magnitude and phase is absolutely constant according
to the presuppositions of the lumped-circuit model. How
could it possibly collapse?

Have I claimed that the lumped model strictly applies? ;-)

No, but someone else has. ;-)
--
73, Cecil http://www.qsl.net/w5dxp

Wanna bet?

The phase shift along the coil plus the phase shift along antenna
conductors does NOT add up 90 degrees when the antenna is 1/4-wave
resonant. It is not anywhere near to it.

Cecil Moore wrote:
John Popelish wrote:

It looks like various magnitudes that you would find at 2 points along
a standing wave, with various fractions of the wave in the inductor as
frequency changes. In spite of hitting these various magnitude
values, there are still only two phases, 0 or 180 anywhere outside the
coil. In some cases, the standing wave goes through a node, inside
the coil and reverses phase from one end of the coil to the other.


Exactly! Now please explain how the nS delay through a coil
could possibly be measured using a signal that abruptly shifts
fixed phase by 180 degrees every 180 degrees.

The only way I can see to do it is to go outside the coil and look at
how the standing current nodes move. Standing wave phase is with
respect to position, not time.

Cecil Moore wrote:
John Popelish wrote:

Cecil Moore wrote:

Please explain how that could be possible with constant
magnitude and phase of the currents through the coil.
The magnitude and phase is absolutely constant according
to the presuppositions of the lumped-circuit model. How
could it possibly collapse?


Have I claimed that the lumped model strictly applies? ;-)


No, but someone else has. ;-)

You trying to get a fight started? "Did you hear what he said about
your wife?"

Reg Edwards wrote:
Wanna bet?

The phase shift along the coil plus the phase shift along antenna
conductors does NOT add up 90 degrees when the antenna is 1/4-wave
resonant. It is not anywhere near to it.

The first problem is that the phase shift along the antenna is about
zero. Having the phase shift along the antenna and coil add to 90
degrees would require a 90 degree shift of current phase across the
coil, regardless of the size of the coil or the antenna. Only the
inductor in an EH antenna drive system has that magical property. I
assume you have to empty the internal coulomb bucket periodically, but
I'm sure that's proprietary.

Pluck a guitar string and watch it oscillate. Notice that all parts of
the string reach their maximum and minimum excursions at the same time.
There's no delay from one point to another. Same thing happens on a
(standing wave) antenna or a shorted or open transmission line, and for
the same reason.

Roy Lewallen, W7EL

wrote:
Cecil Moore wrote:
wrote:
I'm suprised you wouldn't want to learn more about measurements.
I'm surprised you wouldn't want to share your engineering
knowledge, e.g. is it really possible to use a phaseless
signal to measure phase shift? If so, please enlighten us.
I can't figure out how to do it. Since you apparently have
figured it out, please share your knowledge with us.

I think you are the one with a problem, not me. I don't know what a
"phaseless" signal is. Does it come from a phaseless signal generator
through phaseless transmission lines??

I don't see anything Roy said that disagrees with what I measured, so
that's a non-issue.

Roy and I have previously agreed with your measurements. It's
your conclusions about those measurements that he apparently
doesn't seem to understand and neither do I. I'm certainly not
speaking for Roy, but when he points out to you that my
measurements agree with EZNEC, one wonders what that means
in reality.

I haven't seen Roy question anything and he hasn't told me he doesn't
understand anything.

Can you requote his post where he said that, or should I take your word
for that along with the phaseless signal??

"Phaseless signals". What an imaginative creation. If you measure zero
phase angle between two points, you *have* measured the phase shift
between them, and it's zero. Sounds like what Cecil is looking for is a
way to measure a non-zero phase shift when the phase shift is in fact
zero, to make it fit his theory. Sorry, it's zero. Period. If that
doesn't fit the theory, then the theory is faulty.

I said that Cecil's phase measurements agree with EZNEC (and generally
accepted theory) -- there should be almost no phase shift in the current
along the wire. I also said that I couldn't say whether his amplitude
measurements are correct, since Cecil didn't say (at least in the quoted
posting I saw) what the positions along the wire were, just their
distance from each other. But it's a trivial thing to model with EZNEC,
so anyone can easily see and judge for himself. With an antenna that
simple, any disagreement between EZNEC and measurements is almost
certain to be due to either measurement error or failure to make the
antenna like the model, e.g., prevent common mode feedline currents.

Roy Lewallen, W7EL

wrote:
I think you are the one with a problem, not me. I don't know what a
"phaseless" signal is. Does it come from a phaseless signal generator
through phaseless transmission lines??

I apologize, but I actually have to plead complete ignorance on
this subject. You seem to be the expert on using phaseless signals
to measure phase. But I'm willing to learn and it is certainly
considerably more interesting than a tutorial on measurements.

I haven't seen Roy question anything and he hasn't told me he doesn't
understand anything.

Can you requote his post where he said that, or should I take your word
for that along with the phaseless signal??

Please stop asking me to do your research for you. I'm a very
busy person anchoring the bass section in my Methodist Choir's
Easter music and performing a very demanding solo. Have you any
idea how difficult it is for a Homo Sapien to hit low-low C?

Roy said about my measurements:

"The measurement looks good to me. The phase is exactly what EZNEC predicts
-- constant along the wire. The ratio in magnitudes we'd expect depends on
the positions along the wire, not just the spacing. Roy Lewallen, W7EL"

That's why I withdrew my "flawed" measurements and offered Roy's
"exactly" observation instead.

I'm thinking back and it seems to me that Roy reported his
measurements without drawing strange conclusions about them.

But you can lay all the objections to waste simply by explaining
how to measure phase using a source signal that doesn't change
phase. You have asserted that you have done it. Please tell us
how.
--
73, Cecil http://www.qsl.net/w5dxp