Standing-Wave Current vs Traveling-Wave Current
 

Roger wrote:

Congratulations on a clever use of zero resistance loads.

I am probably missing something, but why not just show the currents
and phase in the 'View Antenna' window ?

Standing-Wave Current vs Traveling-Wave Current
 

4nec2 wrote:
Roger wrote:

Congratulations on a clever use of zero resistance loads.

I am probably missing something, but why not just show the currents
and phase in the 'View Antenna' window ?
Maybe I am missing something. I can not get a numeric record of the
phase and current in the "View Antenna" window. I am using version 4.0.

Standing-Wave Current vs Traveling-Wave Current
 

4nec2 wrote:
Roger wrote:

Congratulations on a clever use of zero resistance loads.

I am probably missing something, but why not just show the currents
and phase in the 'View Antenna' window ?

For current phase, EZNEC does not display the same
absolute phase as the "Load Dat" function reports.
That would appear to be a bug in the EZNEC GUI
software.

I'm glad you asked that question. Perhaps W7EL can tell
us why EZNEC does not display the same current phase as
it reports in the "Load Dat" function. EZNEC seems to
display the current amplitude correctly but it is unclear
exactly what EZNEC is displaying when the current phase
box is selected. That's why I used the "Load Dat" feature.

Here is a graphic using the "View Antenna" window for
the EZNEC files TravWave.EZ and StndWave.EZ.

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

Looking at TravWave.EZ with the current phase turned
off, the current displayed is indeed the amplitude of
the current up and down the wire which is essentially
a constant RMS magnitude.

But with the current phase turned on, the display does
not display the same phase reported by "Load Dat". It
displays a cosine function when the actual phase function
is a straight sloping line varying from 0 degrees at the
feedpoint to -90 degrees at the load resistor. What
EZNEC is actually displaying associated with phase
is unclear, confusing, and misleading.

StndWave.EZ has the same unclear display for phase.
The current amplitude is the correct cosine function
but the current phase is misleading. The "Loads Dat"
function says the phase varies from 0 degrees at the
feedpoint to -0.11 deg at the open end of the wire,
i.e. virtually no change at all in phase up and down
the wire. Yet EZNEC displays a cosine function for the
current phase the meaning of which is unclear.

To answer your question, EZNEC does not display phase
when the current phase box is selected. It is unclear
to me exactly what EZNEC is displaying when the current
phase box is selected.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Roger wrote:
Maybe I am missing something. I can not get a numeric record of the
phase and current in the "View Antenna" window. I am using version 4.0.

You do get a *graphic* record of the current amplitude in
the "View Antenna" window. It is unclear exactly what
is displayed when the current phase box is selected.

You do NOT get a numeric record in the View Antenna
window. For a numeric record, you must use the "Loads"
and "Load Dat" feature.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Cecil Moore wrote:
Here is a graphic using the "View Antenna" window for
the EZNEC files TravWave.EZ and StndWave.EZ.

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

Sorry, the graphic only contains information about
TravWave.EZ

Looking at TravWave.EZ with the current phase turned
off, the current displayed is indeed the amplitude of
the current up and down the wire which is essentially
a constant RMS magnitude.

But with the current phase turned on, the display does
not display the same phase reported by "Load Dat". It
displays a cosine function when the actual phase function
is a straight sloping line varying from 0 degrees at the
feedpoint to -90 degrees at the load resistor. What
EZNEC is actually displaying associated with phase
is unclear, confusing, and misleading.

StndWave.EZ ...

Please ignore what I said about StndWave.EZ

To answer your question, EZNEC does not display phase
when the current phase box is selected.

To be more clear. EZNEC does not display the same phase
as reported by the "Loads" feature.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Roger wrote:
4nec2 wrote:
Roger wrote:

Congratulations on a clever use of zero resistance loads.

I am probably missing something, but why not just show the currents
and phase in the 'View Antenna' window ?
Maybe I am missing something. I can not get a numeric record of the
phase and current in the "View Antenna" window. I am using version 4.0.

In all versions, the View Antenna display shows the currents only
graphically and not numerically. There are three ways to find the
numerical value of current at a particular segment:

1. Click the Currents button at the left of the main window. This gives
the currents at all segments.
2. Insert a zero ohm load at the segment of interest and click Load Dat
to see its current.
3. Insert a zero volt voltage (not current) source at the segment of
interest and click Src Dat to see its current.

Roy Lewallen, W7EL

Standing-Wave Current vs Traveling-Wave Current
 

Roy Lewallen wrote:
1. Click the Currents button at the left of the main window. This gives
the currents at all segments.
2. Insert a zero ohm load at the segment of interest and click Load Dat
to see its current.

Why doesn't EZNEC accurately plot those currents on the
antenna display?
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

On Thu, 20 Dec 2007 15:04:36 -0600, Cecil Moore
wrote:

accurately

And this cry in the wilderness from someone who can prove fundamental
principles with +/-40% error. ;-)

Standing-Wave Current vs Traveling-Wave Current
 

Cecil Moore wrote:
Roger wrote:
Maybe I am missing something. I can not get a numeric record of the
phase and current in the "View Antenna" window. I am using version 4.0.

You do get a *graphic* record of the current amplitude in
the "View Antenna" window. It is unclear exactly what
is displayed when the current phase box is selected.

Although one can get a current amplitude plot vs length
from EZNEC, it seems impossible to get a current phase
plot vs length. That's probably why so many people are
confused. Click on "Currents" and transfer that data
to EXCEL to make things a lot clearer.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Cecil Moore wrote:
Cecil Moore wrote:
Here is a graphic using the "View Antenna" window for
the EZNEC files TravWave.EZ and StndWave.EZ.

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

Sorry, the graphic only contains information about
TravWave.EZ

Looking at TravWave.EZ with the current phase turned
off, the current displayed is indeed the amplitude of
the current up and down the wire which is essentially
a constant RMS magnitude.

But with the current phase turned on, the display does
not display the same phase reported by "Load Dat". It
displays a cosine function when the actual phase function
is a straight sloping line varying from 0 degrees at the
feedpoint to -90 degrees at the load resistor. What
EZNEC is actually displaying associated with phase
is unclear, confusing, and misleading.

StndWave.EZ ...

Please ignore what I said about StndWave.EZ

To answer your question, EZNEC does not display phase
when the current phase box is selected.

To be more clear. EZNEC does not display the same phase
as reported by the "Loads" feature.

Cecil,

I presume that this is a silly question, but "Did you read the manual"?

EZNEC is displays the current phase exactly as described in the manual.

Hint: Current is shown as distance from the axis. Current PHASE is shown
by a rotation around the axis, not by the distance from the axis.

73,
Gene
W4SZ