Roy Lewallen wrote:
Since EZNEC has been mentioned so much lately, it's appropriate to point
out that it's able to calculate the current at all points along a
helically modeled loading inductor with what I believe to be very good
accuracy. And it does it without any use or knowledge of presumed
traveling voltage or current waves.

Yet, EZNEC reports the difference in standing wave current and
traveling wave current better than you do.

EZNEC correctly reports the phase of the standing wave current to
be essentially zero all up and down a 1/2WL dipole using small wire.

EZNEC correctly reports the phase of the traveling wave current to
be the number of degrees away from the source in a traveling wave
antenna.

EZNEC clearly recognizes the difference between standing wave current
and traveling wave current. Yet you tried to use standing wave current
with its unchanging phase to measure the phase shift through a coil.
Standing wave current doesn't even change phase through 45 degrees
of wire. Why would you expect it to change phase through 45 degrees
of coil?
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:

EZNEC clearly recognizes the difference between standing wave current
and traveling wave current. Yet you tried to use standing wave current
with its unchanging phase to measure the phase shift through a coil.
Standing wave current doesn't even change phase through 45 degrees
of wire. Why would you expect it to change phase through 45 degrees
of coil?

Not to be a stickler, but didn't you just chastise me for bringing up
coils, and you said you had no interest in discussing them, because
that subject was closed for you?

Make up your mind, please.

John Popelish wrote:
Cecil Moore wrote:

EZNEC clearly recognizes the difference between standing wave current
and traveling wave current. Yet you tried to use standing wave current
with its unchanging phase to measure the phase shift through a coil.
Standing wave current doesn't even change phase through 45 degrees
of wire. Why would you expect it to change phase through 45 degrees
of coil?

Not to be a stickler, but didn't you just chastise me for bringing up
coils, and you said you had no interest in discussing them, because that
subject was closed for you?

Make up your mind, please.

And in any case, the statement about EZNEC is incorrect. As I explained
in a posting a short while ago, EZNEC has no awareness of nor does it
make any use of traveling wave currents or voltages. It calculates only
the total current from fundamental rules which don't involve traveling
waves.

Roy Lewallen, W7EL

Roy Lewallen wrote:
And in any case, the statement about EZNEC is incorrect. As I explained
in a posting a short while ago, EZNEC has no awareness of nor does it
make any use of traveling wave currents or voltages. It calculates only
the total current from fundamental rules which don't involve traveling
waves.

EZNEC reports a different phase for traveling wave currents than
it does for standing wave currents. It does know the difference
although I don't know how it knows. It recognizes the difference
between a terminated line with no reflections and an unterminated
line with reflections.

The current reported by EZNEC for a terminated rhombic, for
instance, is clearly traveling wave current since the phase
changes with distance from the source.

The current reported by EZNEC for a 1/2WL dipole, for instance,
is clearly standing wave current since the phase doesn't
change with distance from the source.

The two kinds of currents are clearly not identical in either
EZNEC or in reality. They are only identical in some human
minds.
--
73, Cecil http://www.qsl.net/w5dxp

Roy Lewallen wrote:
And in any case, the statement about EZNEC is incorrect. As I explained
in a posting a short while ago, EZNEC has no awareness of nor does it
make any use of traveling wave currents or voltages. It calculates only
the total current from fundamental rules which don't involve traveling
waves.

For anyone who thinks EZNEC doesn't report traveling wave currents
differently from standing wave currents, please download the following
files.

http://www.qsl.net/w5dxp/testx.EZ

This is a *traveling wave file*. EZNEC reports the nearly linear phase
of the current from 0 degrees at the source to 90 degrees at the load.
The file comes with a zero load in the center of that 90 degree run.
EZNEC reports the current's phase at 45 degrees at that zero load.

http://www.qsl.net/w5dxp/testy.EZ

Removing the resistive load from testx.EZ turns it into a *standing
wave configuration*. EZNEC reports the phase of the current close
to zero degrees all up and down the wire. The file comes with a
zero load in the center of the same wire as above. EZNEC reports
the current's phase very near zero degrees. The phase is near zero
degrees all up and down wire 2.

Contrary to what you have been told, EZNEC clearly reports the
difference between the traveling wave configuration and the
standing wave configuration. The traveling wave current phase
can be used to measure the phase shift through the wire (or
through a coil). The standing wave current phase cannot.

To summarize: For the traveling wave configuration, the current
magnitude is essentially constant all up and down the line while
the phase shifts smoothly from zero degrees at the source to
90 degrees at the resistive load.

For the standing wave configuration, the current magnitude
follows the familiar cosine envelope from source at zero
degrees to the end of the antenna at 90 degrees. The phase
of the standing wave current is unchanging near zero degrees
all up and down the wire.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:

The testx.EZ file has been renamed to:

http://www.qsl.net/w5dxp/TravWave.EZ

The testy.EZ file has been renamed to:

http://www.qsl.net/w5dxp/StndWave.EZ

The current reported by EZNEC for TravWave.EZ contains the term
cos(kz+wt) It's a traveling wave current, clearly not the same
as a standing wave current.

The current reported by EZNEC for StndWave.EZ contains the terms
cos(kz)*cos(wt) It's a standing wave current, clearly not the
same as a traveling wave current.

Current reported by EZNEC every 10% of wire #2 is presented in
the following table. The currents are obviously very different.
The phase of the traveling wave progresses from 0 to 90 deg
in 90 deg of wire. The phase of the standing wave doesn't
progress beyond 0.11 of of degree.

% along current in current in
wire #2 TravWave.EZ StndWave.EZ

0% 0.9998 at -0.99 deg 0.9996 at 0 deg
10% 0.9983 at -9.39 deg 0.9843 at -0.03 deg
20% 0.9983 at -18.23 deg 0.9454 at -0.05 deg
30% 0.9957 at -27.59 deg 0.8843 at -0.06 deg
40% 0.9949 at -35.96 deg 0.8023 at -0.08 deg
50% 0.9945 at -44.84 deg 0.7014 at -0.09 deg
60% 0.9945 at -54.2 deg 0.584 at -0.09 deg
70% 0.9949 at -62.58 deg 0.4528 at -0.1 deg
80% 0.9956 at -71.43 deg 0.311 at -0.11 deg
90% 0.9965 at -80.27 deg 0.1616 at -0.11 deg
100% 0.9976 at -89.14 deg 0.006073 at -0.11 deg

Some say "current is current". EZNEC disagrees. When
reflected waves are eliminated, EZNEC indeed does accurately
report traveling wave current. EZNEC reports the current
that is there, whether it is traveling wave current or
standing wave current.

I'm trying to learn how to graph the above current magnitude
and phase in Mathcad but not having much luck.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
% along current in current in
wire #2 TravWave.EZ StndWave.EZ

0% 0.9998 at -0.99 deg 0.9996 at 0 deg
10% 0.9983 at -9.39 deg 0.9843 at -0.03 deg
20% 0.9983 at -18.23 deg 0.9454 at -0.05 deg
^^^^^^
Sorry, a typo. Should be 0.9969

30% 0.9957 at -27.59 deg 0.8843 at -0.06 deg
40% 0.9949 at -35.96 deg 0.8023 at -0.08 deg
50% 0.9945 at -44.84 deg 0.7014 at -0.09 deg
60% 0.9945 at -54.2 deg 0.584 at -0.09 deg
70% 0.9949 at -62.58 deg 0.4528 at -0.1 deg
80% 0.9956 at -71.43 deg 0.311 at -0.11 deg
90% 0.9965 at -80.27 deg 0.1616 at -0.11 deg
100% 0.9976 at -89.14 deg 0.006073 at -0.11 deg

--
73, Cecil http://www.qsl.net/w5dxp

On Wed, 05 Apr 2006 12:56:07 GMT, Cecil Moore
wrote:

Sorry, a typo. Should be 0.9969

Let's see, you responded to Roy twice, then responded to yourself, and
then responded to yourself again - DAMN, you are really trying hard to
convince yourself.

In your pursuit of a solitary pleasure, I can't tell which perspective
has the worst prospect: the teacher's, or the student's.

On Tue, 04 Apr 2006 21:18:53 -0400, John Popelish
wrote:

Make up your mind, please.
The triumph of experience over hope.

John Popelish wrote:

Cecil Moore wrote:

EZNEC clearly recognizes the difference between standing wave current
and traveling wave current. Yet you tried to use standing wave current
with its unchanging phase to measure the phase shift through a coil.
Standing wave current doesn't even change phase through 45 degrees
of wire. Why would you expect it to change phase through 45 degrees
of coil?

Not to be a stickler, but didn't you just chastise me for bringing up
coils, and you said you had no interest in discussing them, because that
subject was closed for you?

Make up your mind, please.

My comment above is primarily about standing wave current,
not about coils. Standing wave current phase cannot be used
to measure the phase shift through empty space, wires, or
anything else.
--
73, Cecil http://www.qsl.net/w5dxp