There seems to be mass confusion even among the gurus on
this newsgroup as to the difference between standing-wave
current, as exists on a 1/2WL dipole, vs traveling-wave
current, as exists on a terminated antenna like a rhombic.

I have prepared two EZNEC files that should run on the
free demo version of EZNEC as well as on the commercial
edition. These two files clearly show the difference in
the two types of currents.

The standing-wave example is designed to illustrate
standing-wave current. All of the forward energy is
reflected at the open end of the wire. The total
current displayed by EZNEC is the sum of the forward
and reflected currents which are close to equal.

The traveling-wave example is designed to illustrate
traveling-wave current. Most of the forward energy
is dissipated in the load resistor rather than being
reflected. The total current displayed by EZNEC is
the sum of the forward and reflected currents with
the reflected current minimized to a negligible value.

Each EZNEC file consists of a 1/4WL wire run horizontal
one foot above ground at 4 MHz. In the standing-wave file,
the wire is open and unterminated. In the traveling-wave
file, the wire is terminated to ground by its characteristic
impedance. To view EZNEC's tabulated current at each of the
18 segments along the 1/4WL, simply click on "Load Dat".

The standing-wave file is:

http://www.w5dxp.com/StndWave.EZ

The traveling-wave file is:

http://www.w5dxp.com/TravWave.EZ

In the following results (directly from EZNEC) please
note the almost constant phase reported for the
standing-wave current vs the continuously changing
phase reported for the traveling-wave current.

Here are the values of current at each segment for the
standing-wave example as reported by EZNEC:

EZNEC+ ver. 4.0

standing wave 12/18/2007 9:11:33 AM
--------------- LOAD DATA ---------------
Frequency = 4 MHz

Load 1 Current = 0.9974 A. at -0.01 deg.
Load 2 Current = 0.9874 A. at -0.02 deg.
Load 3 Current = 0.9703 A. at -0.03 deg.
Load 4 Current = 0.9461 A. at -0.04 deg.
Load 5 Current = 0.915 A. at -0.05 deg.
Load 6 Current = 0.8773 A. at -0.06 deg.
Load 7 Current = 0.8332 A. at -0.07 deg.
Load 8 Current = 0.783 A. at -0.08 deg.
Load 9 Current = 0.7271 A. at -0.08 deg.
Load 10 Current = 0.6659 A. at -0.09 deg.
Load 11 Current = 0.5999 A. at -0.09 deg.
Load 12 Current = 0.5295 A. at -0.10 deg.
Load 13 Current = 0.4553 A. at -0.10 deg.
Load 14 Current = 0.3777 A. at -0.10 deg.
Load 15 Current = 0.2974 A. at -0.10 deg.
Load 16 Current = 0.2148 A. at -0.11 deg.
Load 17 Current = 0.1307 A. at -0.11 deg.
Load 18 Current = 0.0447 A. at -0.11 deg.

Here are the values of current at each segment for the
traveling-wave example as reported by EZNEC:

EZNEC+ ver. 4.0

traveling wave 12/18/2007 9:18:19 AM
--------------- LOAD DATA ---------------
Frequency = 4 MHz

Load 1 Current = 0.9992 A. at -3.12 deg.
Load 2 Current = 0.9983 A. at -8.11 deg.
Load 3 Current = 0.9977 A. at -13.08 deg.
Load 4 Current = 0.9972 A. at -18.05 deg.
Load 5 Current = 0.9970 A. at -23.02 deg.
Load 6 Current = 0.9970 A. at -27.99 deg.
Load 7 Current = 0.9973 A. at -32.96 deg.
Load 8 Current = 0.9978 A. at -37.92 deg.
Load 9 Current = 0.9985 A. at -42.87 deg.
Load 10 Current = 0.9993 A. at -47.82 deg.
Load 11 Current = 1.0000 A. at -52.75 deg.
Load 12 Current = 1.0010 A. at -57.67 deg.
Load 13 Current = 1.0030 A. at -62.58 deg.
Load 14 Current = 1.0040 A. at -67.48 deg.
Load 15 Current = 1.0050 A. at -72.36 deg.
Load 16 Current = 1.0060 A. at -77.23 deg.
Load 17 Current = 1.0070 A. at -82.09 deg.
Load 18 Current = 1.0080 A. at -86.97 deg.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
There seems to be mass confusion even among the gurus on
this newsgroup as to the difference between standing-wave
current, as exists on a 1/2WL dipole, vs traveling-wave
current, as exists on a terminated antenna like a rhombic.

I have prepared two EZNEC files that should run on the
free demo version of EZNEC as well as on the commercial
edition. These two files clearly show the difference in
the two types of currents.

Heavily clip.......

The standing-wave file is:

http://www.w5dxp.com/StndWave.EZ

The traveling-wave file is:

http://www.w5dxp.com/TravWave.EZ

clip.....

Hi Cecil,

I tried the files and they work well. Congratulations on a clever use
of zero resistance loads. I have not seen that technique used before
but it certainly allows for a good EZNEC demonstration.

EZNEC is a great program.

73, Roger, W7WKB

Roger wrote:
I tried the files and they work well. Congratulations on a clever use
of zero resistance loads. I have not seen that technique used before
but it certainly allows for a good EZNEC demonstration.

It's a way to "measure" the current without disturbing
the current. Do you see how the EZNEC current has a
reference phase and thus is a "snapshot" in time? Do
you see how traveling-wave current travels and standing-
wave current just appears to stand there? Since EM waves
cannot just stand there and must necessarily move at the
speed of light, a standing-wave is just an artifact of
superposition (a magical illusion for some). It has no
stand-alone existence aside from its forward and reverse
component EM waves that indeed do travel at the speed of
light (adjusted for velocity factor).

EZNEC is a great program.

Yes indeed, like the Smith Chart, it is a great antenna
tool. I've been a satisfied customer for 20 years,
since I first purchased ELNEC. ELNEC and EZNEC
have been great tutors for me. If someone doesn't
want to buy it, the free demo version of EZNEC
available from http://www.eznec.com is quite a free
lunch and although limited to 20 segments, is very
useful on wire dipoles and monopoles and learning
how they work.
--
73, Cecil http://www.w5dxp.com

On Tue, 18 Dec 2007 09:33:23 -0600, Cecil Moore
wrote:

There seems to be mass confusion even among the gurus on
this newsgroup as to the difference between standing-wave
current, as exists on a 1/2WL dipole, vs traveling-wave
current, as exists on a terminated antenna like a rhombic.

:-)
Confusion appears to be selective here, and not to be found generally
in the remainder of the group.

For instance, in the quote above, we are introduced to two antennas
THAT ARE NEVER AGAIN EMPLOYED, AS EXPLICITLY INFERRED, AS THE BASIS OF
COMPARISON!

In short, the author immediately dismissing these practical antennas,
never again approaches the problem as described above. The solution
to this confusion appears to be of no true concern. So, what's the
problem? No question follows in the remainder of the post, only
statements. No statements illustrate the difference between any
antennas that are the source of the presumed confusion. The original
model wires draped 1/200th wavelength above ground are certainly not
to be confused with conventional rhombic, nor dipoles.

Diligent readers would back away from this dead horse.

Modeling a rhombic is not outside the art of the practitioner, only
one practitioner for whom the data does not support the premise for
these antennas (quickly discarded as I have pointed out).

Four 4 wavelength wires built into a symmetric diamond, one source at
22MHz, one load, and the whole model is described. As a variation,
put it in free space, test; repeat with it 65 feet above ground, test.
As another variation, load with a matched R, test; load with an
open/short, test.

What monumental results follow from all results?

65 feet above ground we observe:
w/Rl = 816 Ohms:
I magnitude declines end-to-end due to radiation;
I magnitude varies insignificantly seg-to-seg (1%);
I phase varies ~160-~100 degrees per 10 segments;
I phase inverts every 10 segments.
w/Rl = 1e9 Ohms:
I magnitude declines end-to-end due to radiation;
I magnitude varies seg-to-seg (~10%-~40%);
I phase varies ~160-~100 degrees per 10 segments;
I phase inverts every 10 segments.

In free space we observe:
w/Rl = 816 Ohms:
I magnitude declines end-to-end due to radiation;
I magnitude varies insignificantly seg-to-seg (1%);
I phase varies ~160 degrees per 10 segments;
I phase inverts every 10 segments.
w/Rl = 1e9 Ohms:
I magnitude declines end-to-end due to radiation;
I magnitude varies seg-to-seg (~5%-~25%);
I phase varies ~160 degrees per 10 segments;
I phase inverts every 10 segments.

All variations support the notion of traveling and standing wave
antennas (unless, of course, some novel re-definition of terms is
injected into the debate). The presumption of traveling waves is well
defined in the current data when placing a "matched load" on the
antenna-as-transmission line is performed. The presumption of
standing waves is well defined in the current data when the "matched
load" is opened on the antenna-as-transmission line.

What does not conform to well tailored expectations? The phase swings
under all conditions are well defined, extensive, and repeat with
regularity. Further, we can also observe how ground's proximity, even
with a substantial height against wavelength begins to intrude into
current dynamics.

We can then proceed into where confusion might reside (it not being
found in these antennas): GROUND. Yes, the death embrace of the
original models with GROUND profoundly skews the data. I would note
that there is the usual crafting of the original post to insure
plausible deniability. In short, the reader is left to be astonished
by the data (corrupt as it is, given the tantalizing premise of
Rhombics and Dipoles being so confusing to the crowd of readers) and
to then be lead further away from that initial dismissal of those
antennas, only to be drawn back to them through Byzantine
extrapolations and copious mathematical "proofs."

As always, fun. I doubt anything new in the technical vein will
follow, so I look forward to the parade that is sure to fill this
thread.

73's
Richard Clark, KB7QHC

On Tue, 18 Dec 2007 12:53:06 -0800, Richard Clark
wrote:

We can then proceed into where confusion might reside (it not being
found in these antennas): GROUND. Yes, the death embrace of the
original models with GROUND profoundly skews the data.

Hi All,

Well, I find there is more technical content to dissect in at least
one dead horse.

Let's look at the "traveling wave" model and see what it has to offer
in the cold harsh light of reality.

Right off the bat with its performance: -23.74dB
What could possibly account for all this loss? The "load?"?

Instead of tossing the load, let's toss ground and put this corpse in
free space. It's performance: -0.30dB

I don't know how any math error like this could be used to validate a
model, but the efficiency as an antenna that hugs ground so vigorously
hardly measures up to either a dipole or a rhombic. On the plus side,
confusion certainly offers many vendors an income, and suckers are
born every minute who would love a low noise antenna.

However, what happened to the currents when we discarded ground? Well,
the pristine constant current of the former model plunges right down
the toilet of expectations (while performance shot through the ceiling
at the same time - one has to wonder what was confusing about this?).
Phase change? That cute 90 degrees formerly nudged and cosseted onto
center stage has now been nailed to the floor with no more total
variation than 2.15 degrees. Hard to imagine how a transmission line
could so thoroughly rape its inventor.

Turning to the "standing wave" model, would it be instructive how a
ground free performance might similarly fare?

Right off the bat with its performance: -1.69dB
it would seem a stretch to find any more efficiency (and shows how
that traveling wave model really sucks). However, without ground for
completeness' sake: -0.28dB

However, what happened to the currents when we discarded ground? Well,
roughly the same 2 degree shift we found when the "traveling wave"
model split the sheets with ground, but beyond that, an almost
identical current taper and phase lock-down found with the "traveling
wave" model free of ground (or in comparison to itself close to
ground).

So, is there any substantial difference between the two models once
ground's death grip is released? I will leave that question for
tea-leaf analysis, because engineers would have buried this dead horse
long ago.

***** Irony meter pegged *****

I would like to point out that the only things changed with these
original models was a switch from 2D to 3D analysis to reveal total
loss; and a switch from the ground offered to free space. I look
forward to Cecil, once again, impeaching his own evidence (and
typically without once mentioning the data).

I am sure I have sunken to new lows and once I am exposed for what I
am (an English major), vindication will taste sweeter than wine. (may
as well steal that thunder too)

73's
Richard Clark, KB7QHC

On Tue, 18 Dec 2007 17:42:00 -0800, Richard Clark
wrote:

Let's look at the "traveling wave" model and see what it has to offer
in the cold harsh light of reality.

Right off the bat with its performance: -23.74dB
What could possibly account for all this loss? The "load?"?

Hi All,

Being one to never leave too many unanswered questions (Cecil merely
questions questions); I poured 100W into the original model (the only
change made was from constant I/E to constant P).

In fact, the proximity of ground allowed 99.38 watts to be absorbed by
the load!

How much reaches the load once this dead horse wrenches free from
ground's death grip and is allowed to ascend the stairway to heaven?
0.4982 watts

You heard it here first. ;-)

And, yes, another change (2 total) was made to the ground offered to
make it, instead, free space.

Who knows, maybe the "traveling wave" model is for a new matching
device for greater load efficiency. Unfortunately it would be best
suited for 80M speakers.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
Let's look at the "traveling wave" model and see what it has to offer
in the cold harsh light of reality.

Right off the bat with its performance: -23.74dB
What could possibly account for all this loss? The "load?"?

You are wasting your time. The entire purpose of the model
is to illustrate the phase shift in the traveling wave
current - absolutely no other purpose.

So how do you explain the phase shift in the current which
is obviously traveling wave current?
--
73, Cecil http://www.w5dxp.com

On Tue, 18 Dec 2007 17:42:00 -0800, Richard Clark
wrote:

On Tue, 18 Dec 2007 12:53:06 -0800, Richard Clark
wrote:

We can then proceed into where confusion might reside (it not being
found in these antennas): GROUND. Yes, the death embrace of the
original models with GROUND profoundly skews the data.

Hi All,

Well, I find there is more technical content to dissect in at least
one dead horse.

Let's look at the "traveling wave" model and see what it has to offer
in the cold harsh light of reality.

Well first, mea culpa's to the readership in using Cecil's models
(never a good idea as they did not attend the question he introduced
whereas mine did). However, moving on to the nut of my copping a
plea. I had not noticed that Cecil drove his wires into MiniNEC
ground - something I have never done in all my modeling. So, my
"changes," as reported, were faithful, but very much unbalanced the
implicit return path through that MiniNEC ground.

Being the good analyst, I then considered my previous work in an even
colder, harsher light of brutal reality. What I did was to replace
that ground path with a wire symmetrical to the 60 footer and then
raised the assembly an inch.

Right off the bat with its performance: -23.74dB
-42.04dB
What could possibly account for all this loss? The "load?"?
And through a follow-up last time, the same conclusion. The
transmission line apparent load for a 100W constant power consumes
99.25 watts

Instead of tossing the load, let's toss ground and put this corpse in
free space. It's performance: -0.30dB
-42.20dB

I don't know how any math error like this could be used to validate a
model, but the efficiency as an antenna that hugs ground so vigorously
hardly measures up to either a dipole or a rhombic. On the plus side,
confusion certainly offers many vendors an income, and suckers are
born every minute who would love a low noise antenna.
Now it enjoys nearly 20dB less noise than before my mistake.

However, what happened to the currents when we discarded ground? Well,
the pristine constant current of the former model plunges right down
the toilet of expectations (while performance shot through the ceiling
at the same time - one has to wonder what was confusing about this?).
Phase change? That cute 90 degrees formerly nudged and cosseted onto
center stage has now been nailed to the floor with no more total
variation than 2.15 degrees. Hard to imagine how a transmission line
could so thoroughly rape its inventor.
The current is still not constant (the original model must rely on a
poor return path to accomplish this). The phase does vary by 90
degrees.

As modified, the current slope reveals this is no longer a traveling
wave antenna (but it never was anyway). This can be remedied by
shifting the last load (the apparent transmission line load) to 750
Ohms.

This, of course, improves nothing in performance.

Turning to the "standing wave" model, would it be instructive how a
ground free performance might similarly fare?

Right off the bat with its performance: -1.69dB
-21.43dB
it would seem a stretch to find any more efficiency (and shows how
that traveling wave model really sucks). However, without ground for
completeness' sake: -0.28dB
-21.12dB

However, what happened to the currents when we discarded ground? Well,
Not enough to discuss.
roughly the same 2 degree shift we found when the "traveling wave"
model split the sheets with ground, but beyond that, an almost
identical current taper and phase lock-down found with the "traveling
wave" model free of ground (or in comparison to itself close to
ground).


So, is there any substantial difference between the two models once
ground's death grip is released? I will leave that question for
tea-leaf analysis, because engineers would have buried this dead horse
long ago.

Well, after sifting my own tea-leaves (one has to wonder how this
escaped the intrepid author's scrutiny) - no not much difference after
all. Transmission lines are pretty robust when designed correctly.

However, neither bear any resemblance to the original post's mention
of rhombic or dipole antennas; and my models of those clearly discard
Cecil's confusion over his named currents by using conventional
designs of conventional antennas. After all, who ever heard of a
traveling wave transmission line? [This is probably the only point
Cecil could ever hope to argue as he would immediately seize on the
opportunity to force that term into the canon.]

***** Irony meter pegged *****

I would like to point out that the only things changed with these
original models was a switch from 2D to 3D analysis to reveal total
loss; and a switch from the ground offered to free space. I look
forward to Cecil, once again, impeaching his own evidence (and
typically without once mentioning the data).

I am sure I have sunken to new lows

Having beaten Cecil in the game of analysis, even to my own, I must be
pond scum by now.

and once I am exposed for what I
am (an English major), vindication will taste sweeter than wine. (may
as well steal that thunder too)

Imagine, I got to the wine decanter first too! :-)

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Tue, 18 Dec 2007 17:42:00 -0800, Richard Clark
wrote:

On Tue, 18 Dec 2007 12:53:06 -0800, Richard Clark
wrote:

We can then proceed into where confusion might reside (it not being
found in these antennas): GROUND. Yes, the death embrace of the
original models with GROUND profoundly skews the data.
Hi All,

Well, I find there is more technical content to dissect in at least
one dead horse.

Let's look at the "traveling wave" model and see what it has to offer
in the cold harsh light of reality.

Well first, mea culpa's to the readership in using Cecil's models
(never a good idea as they did not attend the question he introduced
whereas mine did). However, moving on to the nut of my copping a
plea. I had not noticed that Cecil drove his wires into MiniNEC
ground - something I have never done in all my modeling. So, my
"changes," as reported, were faithful, but very much unbalanced the
implicit return path through that MiniNEC ground.

Being the good analyst, I then considered my previous work in an even
colder, harsher light of brutal reality. What I did was to replace
that ground path with a wire symmetrical to the 60 footer and then
raised the assembly an inch.

Right off the bat with its performance: -23.74dB
-42.04dB
What could possibly account for all this loss? The "load?"?
And through a follow-up last time, the same conclusion. The
transmission line apparent load for a 100W constant power consumes
99.25 watts

Instead of tossing the load, let's toss ground and put this corpse in
free space. It's performance: -0.30dB
-42.20dB
I don't know how any math error like this could be used to validate a
model, but the efficiency as an antenna that hugs ground so vigorously
hardly measures up to either a dipole or a rhombic. On the plus side,
confusion certainly offers many vendors an income, and suckers are
born every minute who would love a low noise antenna.
Now it enjoys nearly 20dB less noise than before my mistake.

However, what happened to the currents when we discarded ground? Well,
the pristine constant current of the former model plunges right down
the toilet of expectations (while performance shot through the ceiling
at the same time - one has to wonder what was confusing about this?).
Phase change? That cute 90 degrees formerly nudged and cosseted onto
center stage has now been nailed to the floor with no more total
variation than 2.15 degrees. Hard to imagine how a transmission line
could so thoroughly rape its inventor.
The current is still not constant (the original model must rely on a
poor return path to accomplish this). The phase does vary by 90
degrees.

As modified, the current slope reveals this is no longer a traveling
wave antenna (but it never was anyway). This can be remedied by
shifting the last load (the apparent transmission line load) to 750
Ohms.

This, of course, improves nothing in performance.

Turning to the "standing wave" model, would it be instructive how a
ground free performance might similarly fare?

Right off the bat with its performance: -1.69dB
-21.43dB
it would seem a stretch to find any more efficiency (and shows how
that traveling wave model really sucks). However, without ground for
completeness' sake: -0.28dB
-21.12dB

However, what happened to the currents when we discarded ground? Well,
Not enough to discuss.
roughly the same 2 degree shift we found when the "traveling wave"
model split the sheets with ground, but beyond that, an almost
identical current taper and phase lock-down found with the "traveling
wave" model free of ground (or in comparison to itself close to
ground).

So, is there any substantial difference between the two models once
ground's death grip is released? I will leave that question for
tea-leaf analysis, because engineers would have buried this dead horse
long ago.

Well, after sifting my own tea-leaves (one has to wonder how this
escaped the intrepid author's scrutiny) - no not much difference after
all. Transmission lines are pretty robust when designed correctly.

However, neither bear any resemblance to the original post's mention
of rhombic or dipole antennas; and my models of those clearly discard
Cecil's confusion over his named currents by using conventional
designs of conventional antennas. After all, who ever heard of a
traveling wave transmission line? [This is probably the only point
Cecil could ever hope to argue as he would immediately seize on the
opportunity to force that term into the canon.]

***** Irony meter pegged *****

I would like to point out that the only things changed with these
original models was a switch from 2D to 3D analysis to reveal total
loss; and a switch from the ground offered to free space. I look
forward to Cecil, once again, impeaching his own evidence (and
typically without once mentioning the data).

I am sure I have sunken to new lows

Having beaten Cecil in the game of analysis, even to my own, I must be
pond scum by now.

and once I am exposed for what I
am (an English major), vindication will taste sweeter than wine. (may
as well steal that thunder too)

Imagine, I got to the wine decanter first too! :-)

73's
Richard Clark, KB7QHC

Cecil's decanter has too much lead in the glass.
73,
Tom Donaly, KA6RUH

Richard Clark wrote:
As modified, the current slope reveals this is no longer a traveling
wave antenna (but it never was anyway). This can be remedied by
shifting the last load (the apparent transmission line load) to 750
Ohms.

Duhhhhhhhh! When you changed the conditions, you changed
the characteristic impedance. The reason for your confusion
is obvious below.

This, of course, improves nothing in performance.

This is not a performance issue. This is a current phase
issue. The purpose for the existence of that EZNEC file
is to illustrate traveling-wave current - nothing else.

After all, who ever heard of a traveling wave transmission line?

Who indeed? Richard, FYI, a transmission line terminated
in its characteristic impedance *IS* a traveling wave
transmission line. Do you understanding the meaning of
a "flat" transmission line? A flat transmission line *is*
a traveling wave transmission line. Here is one modeled
in EZNEC. Download and click on "Load Dat".

http://www.w5dxp.com/stub514R.EZ

Why is the ignorance level about traveling waves so high
on this newsgroup? It's the result of those inadequate
lumped circuit models.
--
73, Cecil http://www.w5dxp.com