Current through coils
 

wrote:
W8JI wrote:
"By the way, I swept S12 phase with my network analyzer on a
100uH inductor a few hours ago while working on a phasing
system. The phase shift through that series inductor was about
-60 or -70 degrees on 1 MHz, ... "

Once again Cecil's famous selective editing allows him to remove things
from context and change the results to suit his unusual ideas.

Noted is your complete lack of technical response which is obvious
by its absence. Were you fibbing when you said you measured "-60 or
-70 degrees on 1 MHz"?

I didn't change a thing, Tom. That is an exact quote from you. The
paragraph above and below were about other topics.

This is why I think getting into a long technical discussion with Cecil
is a waste of time.

You have never engaged me in even a short technical discussion.
99% of the technical content of my postings are ignored by you.
One wonders why.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

My oh my! I looked down and saw that there were many hundreds of messages
that I had not read - might have been twice that number, but I do have an
automatic purge turned on.

For two weeks there has been a theological discussion going on.

All of this was thrashed out years ago - perhaps it was at Worms many
centuries ago.

A lesson from an old man: I ran a rural zoning board for 18 years,
McLaughlin's rule for running the meeting was that everyone could have a say
and one rebuttal after everyone had had their say. (The perversity that was
sometimes exhibited at the zoning board meeting quite exceeded anything you
gentle people could put forth.)

Perhaps a modern equivalent that is applicable is: do not feed the
trolls

This is a great group. 73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:

Current through coils
 

Gene Fuller wrote:
I have sent the files to you, as requested.
It is always possible that I made a mistake in the modeling. If so, I am
confident the entire world will know in short order. 8-)

Ten turns per foot is not what I had in mind for modeling my 4TPI
75m bugcatcher coil and the EZNEC guideline violations are a little
discouraging. I have an EZNEC file for a omnidirectional 20 dBi
antenna if you would like to have it. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Cecil,

I take your cryptic message to mean there was something wrong with the
files I sent you. If that is your message then I don't understand.

I just went back and checked the EZ files. The coil consists of 25 turns
over a six-inch length. How does that calculate out to ten turns per foot?

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

I have sent the files to you, as requested.
It is always possible that I made a mistake in the modeling. If so, I
am confident the entire world will know in short order. 8-)


Ten turns per foot is not what I had in mind for modeling my 4TPI
75m bugcatcher coil and the EZNEC guideline violations are a little
discouraging. I have an EZNEC file for a omnidirectional 20 dBi
antenna if you would like to have it. :-)

Current through coils
 

Hohn Popelish wrote:
"I guess this depends on the official definition of "slow wave."

My dictionary of electronics defines "slow-wave circuit" as: "-A
microwave circuit in which the phase velocity of the waves is
considerably below the speed of light. Such waves are used in
traveling-wave tubes."

William I. Orr wrote on page 6.11 of the 22nd edition of the "Radio
Handbook":
"Spaced closely around the (TWT) beam is a circuit, in this case a helix
of tightly wound wire, capable of propagating a slow wave. The r-f
energy travels along the wire at the velocity of light but, because of
the helical path, the energy propagates along the length of the tube at
a considerably lower velocity than is determined primarily by the pitch
of the helix." (I think Mr. Orr probably wrote: that is determined
primarily by the pitch of the helix.)

I`ve seen several mentions of "slow wave" in the literature and it
always meant slower than the speed of light. There is no need to limit
the definition to microwaves as the coil slows the velocity across
because the wave is guided by the wire wrapped around its form. The wire
is longer than the coil form.

Best regards, Richard Harrison, KB5WZI

Current through coils
 

Gene Fuller wrote:
Cecil,
I just went back and checked the EZ files. The coil consists of 25 turns
over a six-inch length. How does that calculate out to ten turns per foot?

First, thanks for sending me those files. I have never been
able to generate a 4 TPI coil in EZNEC because of proximity
guidelines. How did you accomplish that?

Second, I thought EZNEC stored the design specifications
for the latest created coil and I was mistaken about that.
EZNEC must default to ten turns per foot.

However, the antenna is almost 12 feet tall, not the agreed
upon 8 feet. It would take a bigger coil to resonate an
8 foot antenna at 4 MHz. Bigger coil = more delay.

And I'm not encouraged by those numerous EZNEC guideline
violations. Download http://www.qsl.net/w5dxp/SUPRGAIN.EZ
for an omni-directional 20 dBi gain antenna that violates
the EZNEC guidelines. Incidentally, there seems to be a bug
in EZNEC. When I try to save the segmentation errors to a
file, EZNEC barfs and closes. I can't get a look at all
the errors so I don't know what they are.

I will continue to tweak the files, like adding enough coil
to bring an 8 foot antenna to resonance.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Harrison wrote:
Hohn Popelish wrote:
"I guess this depends on the official definition of "slow wave."

My dictionary of electronics defines "slow-wave circuit" as: "-A
microwave circuit in which the phase velocity of the waves is
considerably below the speed of light. Such waves are used in
traveling-wave tubes."

William I. Orr wrote on page 6.11 of the 22nd edition of the "Radio
Handbook":
"Spaced closely around the (TWT) beam is a circuit, in this case a helix
of tightly wound wire, capable of propagating a slow wave. The r-f
energy travels along the wire at the velocity of light but, because of
the helical path, the energy propagates along the length of the tube at
a considerably lower velocity than is determined primarily by the pitch
of the helix." (I think Mr. Orr probably wrote: that is determined
primarily by the pitch of the helix.)

I`ve seen several mentions of "slow wave" in the literature and it
always meant slower than the speed of light. There is no need to limit
the definition to microwaves as the coil slows the velocity across
because the wave is guided by the wire wrapped around its form. The wire
is longer than the coil form.

It seems that these references are not particularly concerned with the
dimensions of the coil with respect to wavelength, or with the mode of
propagation within the coil. I suspect that the term has different
meanings to different specialties.

Current through coils
 

Gene Fuller wrote:
I take your cryptic message to mean there was something wrong with the
files I sent you. If that is your message then I don't understand.

Your files contain multiple geometry proximity errors. Here is
what EZNEC says about your file:

http://www.qsl.net/w5dxp/ezerror.GIF

I started to print out the error file until I discovered it
is 142 pages long.

It seems to be impossible to model 4 MHz, 4 TPI coils in
EZNEC without multitudes of proximity errors. Proximity
errors result in gross errors in EZNEC results.

I'm sorry, Gene, but the results of your simulation cannot
be trusted.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Cecil,

As you know, generating the helix coils and using them are two separate
things. I have only EZNEC version 3, which does not support automatic
helix generation. However, there does not appear to be any reason why
helices cannot be used in EZNEC version 3. That is what I did. I copied
your wires, edited them, and re-input into EZNEC.

As for the height, you asked for an 8 foot whip. I adjusted my model
until I got to a 10 foot whip. As I stated, I quit at that point. If you
choose to further refine the model, be my guest. I doubt that you will
find the magic wormhole into the parallel universe where everything is
radically different.

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

Cecil,
I just went back and checked the EZ files. The coil consists of 25
turns over a six-inch length. How does that calculate out to ten turns
per foot?


First, thanks for sending me those files. I have never been
able to generate a 4 TPI coil in EZNEC because of proximity
guidelines. How did you accomplish that?

Second, I thought EZNEC stored the design specifications
for the latest created coil and I was mistaken about that.
EZNEC must default to ten turns per foot.

However, the antenna is almost 12 feet tall, not the agreed
upon 8 feet. It would take a bigger coil to resonate an
8 foot antenna at 4 MHz. Bigger coil = more delay.

And I'm not encouraged by those numerous EZNEC guideline
violations. Download http://www.qsl.net/w5dxp/SUPRGAIN.EZ
for an omni-directional 20 dBi gain antenna that violates
the EZNEC guidelines. Incidentally, there seems to be a bug
in EZNEC. When I try to save the segmentation errors to a
file, EZNEC barfs and closes. I can't get a look at all
the errors so I don't know what they are.

I will continue to tweak the files, like adding enough coil
to bring an 8 foot antenna to resonance.

Current through coils
 

Cecil,

I did what you "challenged", with the exception of the exact whip
length. (And the version I sent had a total height of 11 feet 9 inches,
which is not absurdly unreasonable.)

I have to say I am surprised that it took you more than 24 hours to
misinterpret what I sent (10 turns per foot) and then to blame the tools.

I don't see any of the errors on my computer.

There is little point of carrying this any further. You already stated
that the results did not make technical sense to you and that perhaps
EZNEC cannot be used for this task. I cannot repair your "technical
sense", and I have no control over the capabilities of EZNEC.


73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

I take your cryptic message to mean there was something wrong with the
files I sent you. If that is your message then I don't understand.


Your files contain multiple geometry proximity errors. Here is
what EZNEC says about your file:

http://www.qsl.net/w5dxp/ezerror.GIF

I started to print out the error file until I discovered it
is 142 pages long.

It seems to be impossible to model 4 MHz, 4 TPI coils in
EZNEC without multitudes of proximity errors. Proximity
errors result in gross errors in EZNEC results.

I'm sorry, Gene, but the results of your simulation cannot
be trusted.