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John KD5YI wrote:

"Cecil Moore" wrote in message
...
John KD5YI wrote:
I think any inductor with the same inductance, Q, and self-resonant
frequency will give the same velocity factor and delay as your
Bugcatcher.

That may or may not be true - I don't have an
opinion one way or another - and it is NOT part
of my argument. My argument deals only with
75m Texas Bugcatcher coils and other large air-
core loading coils used on 75m.

If it IS true, then the point I tried to make that you are making a
distributed component from a lumped one is valid. That's what caused me
to object to your earlier post.

And, by the way, I feel the same way you do except about people who are
afraid to consider lumped components. Perhaps they do not have what it
takes to judge when a proper substitution can be made.

John

Anyone can take a small inductor, such as Roy described, and try to
analyze all the currents and such in it using a distributed model at low
or moderate frequencies. If they do, though, they'll just come up with
what they'd have come up with treating their small inductor as a
lumped element. Cecil has distributed elements on the brain. It's what
comes of falling in love with your own theories.
73,
Tom Donaly, KA6RUH

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Jim Kelley wrote:
Presumably there is a lower limit to the number of turns the coil would
have to have, or an upper limit to the pitch angle, in order to behave
as described - a helical sheath. Tesla coils usually have at least a
few hundred turns wound closely together, and often operate at
wavelengths considerably longer that 75 meters. One could easily argue
that 30 turns do not a Tesla coil make, in which case Eq. 32 would not
apply.

Dr. Corum says that it behaves as a helical sheath when
it is electrically longer than 15 degrees (0.04WL). The
frequency doesn't matter - just the electrical length.
Of course, it takes more turns at a lower frequency
since the reactance is proportional to frequency. Eq.
32 is not concerned with the number of turns, just that
the coil is electrically longer than 15 degrees and is
therefore outside the range for which the lumped-circuit
model is valid.

Note that the title of the paper is: "RF Coils,
Helical Resonators and Voltage Magnification
by Coherent Spatial Modes". "Tesla coil" does not
even appear in the title.

A Tesla coil can be 1/4WL self-resonant all by itself.
Thus, 30 turns could easily be a Tesla coil over a
certain range of HF frequencies.

Some Tesla coils have a top hat and are operated below
their 1/4WL self-resonant frequency.

In Dr. Corum's paper, take a look at "Figure 2, A
capacitively tuned distributed resonator" and tell
us how it differs from a 75m mobile antenna with a
top hat.

The 1/4WL self-resonant frequency for a 75m Texas
Bugcatcher coil has been measured at ~6.5 MHz where
it is known to be electrically 90 degrees long. Why
does anyone have a problem with it being electrically
40 degrees long on 4 MHz?

In "Fields and Waves ...", by Ramo and Whinnery, the
analysis of a helical sheath assumes an infinitely
long helical sheath for the purpose of eliminating
reflections. Does that ring a bell? Hint: The current
on a standing-wave antenna cannot be used to measure
phase shift or delay. Yet, that is exactly what w8ji
and w7el tried to do.

I once turned my 75m mobile Texas Bugcatcher system
into a Tesla coil. I had a latch to which I could
connect the top ball of the antenna when I needed
to lean it over for more clearence. I was at a hamfest
at night and had forgotten I had the antenna latched
down. I started transmitting and my friend told me
I was drawing a two-inch arc from the tip of my antenna
to the pickup body. It was indeed "Voltage Magnification
by Coherent Spatial Modes".

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

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John KD5YI wrote:
If it IS true, then the point I tried to make that you are making a
distributed component from a lumped one is valid. That's what caused me
to object to your earlier post.

There are coils for which the lumped-circuit model
is valid.

There are coils for which the lumped-circuit model
is not valid.

I am only interested in discussing coils for which
the lumped-circuit model is invalid, i.e. coils that
are electrically longer than 15 degrees, e.g. a large
air-core 75m Texas Bugcatcher coil which measures
about 40 degrees on 4 MHz.

I honestly don't know if the lumped-circuit model
works for 70 uH toroidal coils. I do know it doesn't
work for a 75m Texas Bugcatcher coil.

The people who insist on analyzing tiny toroidal coils
instead of 75m Texas Bugcatcher coils are afraid of
the technical truth and it's easy to see why.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

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Art Unwin wrote:
Does your photon come in different sizes,
color and potential energy?

It comes in different wavelengths. It certainly
comes in any and all colors and frequencies outside
the range of "color". All of its energy is the
result of its speed of light velocity. It has
zero rest mass. It has the equivalent of mass
when traveling at the speed of light. m=e/c^2
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

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Tom Donaly wrote:
Meaning you don't want anyone to disagree with you.

What I invite is someone disagreeing with me about
a 75m Texas Bugcatcher coil along with some technical
proof that I am wrong. All I have gotten so far is
ad hominem attacks. Where's the beef?

Dr. Corum's empirically-based equations do not work
for toroidal inductors so they are outside the scope
of my discussion. Why not discuss the most common
large air-core coils used for loading 75m mobile
antennas?

No he wouldn't. You don't know what he would have measured.

I have exactly the same coil that Tom used for his
"measurements". I have measured the traveling wave
delay through the coil by loading it with a 5k
resistor to eliminate reflections. I do know what
he would measure if he would only run the experiment
correctly. You could do it too if you so chose. x and
y are the current sample points.

source---x-Tom's coil-y--5k load
+-------------------------+

Maxwell's equations don't say anything about "slow-wave
structures."

If you are saying that Maxwell's equations are invalid
for slow-wave structures, your argument is with Ramo,
Whinnery, and Dr. Corum, not with me.

http://www.w8ji.com/agreeing_measurements.htm

"As described in my posting on rraa of November 11,
the inductor 'replaces' about 33 electrical degrees
of the antenna."

Are you sure that isn't a quote from Reg Edwards, whose ideas
you stole in the first place?

You are free to access the above web page to see who
wrote it. If Dr. Corum stole Reg's ideas, he should
have given him the credit. Dr. Corum does provide
50 references for his paper but Reg is not one of them.
However, here is a partial list:
7. J. D. Kraus, "Antennas"
19. F. E. Terman, "Resonant Lines in Radio Circuits"
23. J. D. Ryder, "Networks, Lines, and Fields"
29. S. Ramo and J. R. Whinnery, "Fields and Waves in Modern Radio"
30. R. W. P. King, "Electromagnetic Engineering"
43. M. Born and E. Wolf, "Principles of Optics"
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

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Tom Donaly wrote:
Anyone can take a small inductor, such as Roy described, and try to
analyze all the currents and such in it using a distributed model at low
or moderate frequencies. If they do, though, they'll just come up with
what they'd have come up with treating their small inductor as a
lumped element.

One wonders why some people insist on a "small
toroidal inductor" which obviously agrees with
the lumped-circuit model instead of analyzing
a 75m Texas Bugcatcher loading coil which just
as obviously violates the presuppositions of
the lumped-circuit model.

Instead of the "small toroidal inductor", let's
discuss w8ji's 100 turn, 2" diameter, 10 inch
long air-core coil through which he measured that
ridiculous 3 nS delay after which w7el posted some
"agreeing measurements" while asserting that the
electrical length of the coil was 33 degrees.

Does anyone else realize that 33 degrees in 3 nS
at 4 MHz is faster than light speed?

Are you guys so afraid of losing face that you
are willing to post technical falsehoods?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

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Cecil Moore wrote:
Tom Donaly wrote:
Meaning you don't want anyone to disagree with you.

What I invite is someone disagreeing with me about
a 75m Texas Bugcatcher coil along with some technical
proof that I am wrong. All I have gotten so far is
ad hominem attacks. Where's the beef?

Dr. Corum's empirically-based equations do not work
for toroidal inductors so they are outside the scope
of my discussion. Why not discuss the most common
large air-core coils used for loading 75m mobile
antennas?

No he wouldn't. You don't know what he would have measured.

I have exactly the same coil that Tom used for his
"measurements". I have measured the traveling wave
delay through the coil by loading it with a 5k
resistor to eliminate reflections. I do know what
he would measure if he would only run the experiment
correctly. You could do it too if you so chose. x and
y are the current sample points.

source---x-Tom's coil-y--5k load
+-------------------------+

Maxwell's equations don't say anything about "slow-wave
structures."

If you are saying that Maxwell's equations are invalid
for slow-wave structures, your argument is with Ramo,
Whinnery, and Dr. Corum, not with me.

http://www.w8ji.com/agreeing_measurements.htm

"As described in my posting on rraa of November 11,
the inductor 'replaces' about 33 electrical degrees
of the antenna."

Are you sure that isn't a quote from Reg Edwards, whose ideas
you stole in the first place?

You are free to access the above web page to see who
wrote it. If Dr. Corum stole Reg's ideas, he should
have given him the credit. Dr. Corum does provide
50 references for his paper but Reg is not one of them.
However, here is a partial list:
7. J. D. Kraus, "Antennas"
19. F. E. Terman, "Resonant Lines in Radio Circuits"
23. J. D. Ryder, "Networks, Lines, and Fields"
29. S. Ramo and J. R. Whinnery, "Fields and Waves in Modern Radio"
30. R. W. P. King, "Electromagnetic Engineering"
43. M. Born and E. Wolf, "Principles of Optics"

I didn't write that the Corums stole Reg's ideas, I wrote that you did.
You know that. Quit trying to hide behind authority. Do you really think
that the people who wrote the references you cite, if they were all
alive today, would agree with you? Ha, ha, ha. Nice try, Cecil.
73,
Tom Donaly, KA6RUH

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Cecil Moore wrote:
Jim Kelley wrote:
Presumably there is a lower limit to the number of turns the coil
would have to have, or an upper limit to the pitch angle, in order to
behave as described - a helical sheath. Tesla coils usually have at
least a few hundred turns wound closely together, and often operate at
wavelengths considerably longer that 75 meters. One could easily
argue that 30 turns do not a Tesla coil make, in which case Eq. 32
would not apply.

Dr. Corum says that it behaves as a helical sheath when
it is electrically longer than 15 degrees (0.04WL). The
frequency doesn't matter - just the electrical length.

:-) And obviously it's electrical length depends on Vp, which depends on
whether it behaves as a helical sheath.

Note that the title of the paper is: "RF Coils,
Helical Resonators and Voltage Magnification
by Coherent Spatial Modes". "Tesla coil" does not
even appear in the title.

Are you trying to imply that the paper isn't about Tesla coils?

In Dr. Corum's paper, take a look at "Figure 2, A
capacitively tuned distributed resonator" and tell
us how it differs from a 75m mobile antenna with a
top hat.

Hopefully you're not serious. Because, borrowing from Richard Clark,
it's a 'cartoon'.

The 1/4WL self-resonant frequency for a 75m Texas
Bugcatcher coil has been measured at ~6.5 MHz where
it is known to be electrically 90 degrees long. Why
does anyone have a problem with it being electrically
40 degrees long on 4 MHz?

Maybe it is. I happen to think that because of its simplicity, it's an
attractive notion. But it's not clear to me that the article applies to
coils with these parameters, and I haven't seen any (reputable)
empirical evidence to support it.

In "Fields and Waves ...", by Ramo and Whinnery, the
analysis of a helical sheath assumes an infinitely
long helical sheath for the purpose of eliminating
reflections. Does that ring a bell? Hint: The current
on a standing-wave antenna cannot be used to measure
phase shift or delay. Yet, that is exactly what w8ji
and w7el tried to do.

What do you suppose Corum^2 meant when they wrote "Experimentally, the
wave velocity and velocity factor may be measured by determining the
axial length of the standing wave pattern on the helical structure"?

I once turned my 75m mobile Texas Bugcatcher system
into a Tesla coil. I had a latch to which I could
connect the top ball of the antenna when I needed
to lean it over for more clearence. I was at a hamfest
at night and had forgotten I had the antenna latched
down. I started transmitting and my friend told me
I was drawing a two-inch arc from the tip of my antenna
to the pickup body. It was indeed "Voltage Magnification
by Coherent Spatial Modes".

No offense, but some of their work seems aimed squarely at the 'Art
Bell' crowd. Describing constructive interference as "voltage
magnification" is an example. It's as if they were publishing in the
19th century.

ac6xg

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Tom Donaly wrote:
I didn't write that the Corums stole Reg's ideas, I wrote that you did.

But I am only quoting Drs. Corum, not Reg. If anyone
stole Reg's ideas, it was Dr. Corum, not I.

Do you really think
that the people who wrote the references you cite, if they were all
alive today, would agree with you?

As a matter of fact, Dr. Balanis did agree with me
when I took his antenna class at ASU in the early
90's. There were some Motorola people in the class
who asked, "Why do Intel people know so much about
antennas?" Dr. Balanis and I worked closely together
on a joint ASU/Intel project.

The complete absence of technical rebuttal in your
posting is noted. I don't know much about you, Tom,
but you seem to be more ad hominem than technical.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

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On May 7, 7:51*am, Cecil Moore wrote:
Tom Donaly wrote:
Meaning you don't want anyone to disagree with you.

What I invite is someone disagreeing with me about
a 75m Texas Bugcatcher coil along with some technical
proof that I am wrong. All I have gotten so far is
ad hominem attacks. Where's the beef?

Dr. Corum's empirically-based equations do not work
for toroidal inductors so they are outside the scope
of my discussion. Why not discuss the most common
large air-core coils used for loading 75m mobile
antennas?

No he wouldn't. You don't know what he would have measured.

I have exactly the same coil that Tom used for his
"measurements". I have measured the traveling wave
delay through the coil by loading it with a 5k
resistor to eliminate reflections. I do know what
he would measure if he would only run the experiment
correctly. You could do it too if you so chose. x and
y are the current sample points.

source---x-Tom's coil-y--5k load
* *+-------------------------+

Maxwell's equations don't say anything about "slow-wave
structures."

If you are saying that Maxwell's equations are invalid
for slow-wave structures, your argument is with Ramo,
Whinnery, and Dr. Corum, not with me.

http://www.w8ji.com/agreeing_measurements.htm

"As described in my posting on rraa of November 11,
the inductor 'replaces' about 33 electrical degrees
of the antenna."

Are you sure that isn't a quote from Reg Edwards, whose ideas
you stole in the first place?

You are free to access the above web page to see who
wrote it. If Dr. Corum stole Reg's ideas, he should
have given him the credit. Dr. Corum does provide
50 references for his paper but Reg is not one of them.
However, here is a partial list:
7. J. D. Kraus, "Antennas"
19. F. E. Terman, "Resonant Lines in Radio Circuits"
23. J. D. Ryder, "Networks, Lines, and Fields"
29. S. Ramo and J. R. Whinnery, "Fields and Waves in Modern Radio"
30. R. W. P. King, "Electromagnetic Engineering"
43. M. Born and E. Wolf, "Principles of Optics"
--
73, Cecil, IEEE, OOTC, *http://www.w5dxp.com

I agree whole heartedly. Maxwell never included slow waves which is a
result of lumped loads. Maxwell equations studies have been rigorous
with respect to accounting for all forces involved in radiation for
maximum efficiency. It stands to reason then that for efficiency a
load is not valid. Thus Reg was correct in seeing a transmission line
as an antenna with just distributed loads when the length is in terms
of a WL i.e. in equilibrium. Thus Kraus's antennas are not in
equilibrium and thus deviated away from Maxwell's laws. Same goes for
Corum ! And Ramo still talks of waves so he is in the same bracket.
All electrical engineering turns topsey turvey
when engineers are forced to consider particles instead of waves and I
will be the leader of that change that will stop CERN in its tracks
Art