Current through coils
 

Dave wrote:
I thought there is/was a restriction that "Everything" must include "a
significant portion of a wavelength". :-)

A lumped-circuit inductance is *NEVER* a significant
portion of a wavelength, by definition and presupposition.
That's the argument being put forth by the lumped-circuit
gurus. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Tom Donaly wrote:
You're right, not strange at all.

In his posting, Richard C. proved he doesn't know how to turn on
the 'Current Phase' option in EZNEC, proved he cannot use a formula
to extract a valid calculation, proved he doesn't know how to
add phase angles, and you are agreeing with him? And you accuse
me of not understanding what I read?
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Clark wrote:
Cecil Moore wrote:
I said something about +/- 50% accuracy.
The linear delay calculation is off by 59%, not too far from
my 50% rough estimate.

error is growing faster than the national debt. ;-)

Now, that is certainly a lie. :-) Remember, W8JI said that
any answer is better than no answer. That presumably includes
his wrong answers. :-)

Stretching your
tolerance for error to fit your argument can lead to any conclusion.

It's not a tolerance for error. It's a recognition that the
answer is, so far, unknown. I've said it befo The delay
through the coil is what it is and we don't know exactly what
it is. That it is difficult to estimate or measure has absolutely
no effect on its value in reality.

What we know for sure is that the presuppositions of the
lumped-circuit model indeed do violate the laws of physics.
Faster than light propagation through a coil comes to mind.

I am admittedly surprised to see the velocity factor fall
so rapidly with frequency. My surprise has absolutely no
effect on reality. I just use the scientific method to
adjust my concepts and move on. However, to paraphrase an old
TV commercial, "It's not nice to fool Father Guru". The earth
may reduce to a quantum singularity when the r.r.a.a gurus
recognize their errors. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

John Popelish wrote:
Not if the lumped inductor model includes lumps of capacitance that
represent the strays to ground. Lumped LC networks exhibit phase shift,
also.

But please remember the original assertions by the gurus. There
is ZERO phase shift through an inductor. There is ZERO amplitude
change through an inductor. This can easily be proven by observing
the lumped inductances in EZNEC. W7EL shot down those arguments
by installing the helix feature in EZNEC. :-)

Never blame malice when ignorance will suffice.

If this person has to confess between ignorance and malicious
behavior, I am sure he would go to jail rather than admit
any ignorance.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

I thought there is/was a restriction that "Everything" must include
"a
significant portion of a wavelength".

===================================

There are no problems. A very short coil behaves as a very short
transmission line.
----
Reg.

Current through coils
 

Reg is correct. Even a very short structure, much shorter than a
wavelength, acts like a transmission line. A short structure just acts
like a short transmission line. It's just that if it's short, there are
simpler ways to analyze it which will get us essentially the same
answer. But we can use full blown transmission line analysis on any
structure if we choose, and should get the correct answer.

Roy Lewallen, W7EL

Dave wrote:
EVERYTHING????

I thought there is/was a restriction that "Everything" must include "a
significant portion of a wavelength".

:-)

Reg Edwards wrote:

EVERYTHING has Inductance, Capacitance and Resistance, and therefore
behaves as a transmission line.
----
Reg, G4FGQ

Current through coils
 

Cecil Moore wrote:
5.5 MHz: 14.1 deg, 5.89 MHz: 15.7 deg, 6 MHz: 16.2 deg,
7 MHz: 21.4 deg, 8 MHz: 29.5 deg, 9 MHz: 45.9 deg,
10 MHz: 89 deg, 11 MHz: 141.4 deg, 12 MHz: 163.0 deg,
13 MHz: 172.3 deg, 13.7 MHz: 183.82 deg.

I just bought Mathcad and am trying to learn to use it.
The graph of the above data is really interesting. Somewhat
like a sine function, this curve has an inflection point
around 10 MHz where the phase shift is changing most rapidly.
On either side of 10 MHz, it doesn't change as rapidly.
10 MHz appears to be the 1/8 wavelength point where
|Z0| = |XL|.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Reg Edwards wrote:
I thought there is/was a restriction that "Everything" must include

"a

significant portion of a wavelength".


===================================

There are no problems. A very short coil behaves as a very short
transmission line.
----
Reg.



I'm glad to know that I can substitute a coil of wire every time I
need a transmission line. So tell me, Reg, what
are the specs on the coil I'd need to make a transmission line
transformer to match 75 ohms to 325.33 ohms?
73,
Tom Donaly, KA6RUH

Current through coils
 

Cecil Moore wrote:

Tom Donaly wrote:

You're right, not strange at all.


In his posting, Richard C. proved he doesn't know how to turn on
the 'Current Phase' option in EZNEC, proved he cannot use a formula
to extract a valid calculation, proved he doesn't know how to
add phase angles, and you are agreeing with him? And you accuse
me of not understanding what I read?

What about figure 2, Cecil?
73,
Tom Donaly, KA6RUH

Current through coils
 

Roy Lewallen wrote:

Reg is correct. Even a very short structure, much shorter than a
wavelength, acts like a transmission line. A short structure just acts
like a short transmission line. It's just that if it's short, there are
simpler ways to analyze it which will get us essentially the same
answer. But we can use full blown transmission line analysis on any
structure if we choose, and should get the correct answer.

Seems that you agree that the distributed network model works for
all common problems. That makes sense since the distributed network
model is a superset of the lumped-circuit model.

Using Dr. Corum's rule that models should be switched at 15 degrees,
15 degrees of a 450 ohm transmission line will transform 50+j0 ohms
to 54+j120 ohms. The difference in 50 ohm SWR is 7:1 Vs 1:1. That
seems like a pretty large error to me just to be able to stick
with the lumped-circuit model.
--
73, Cecil http://www.qsl.net/w5dxp