Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
AI4QJ wrote:
That is his "obvious" explanation. He should remove that from his
webpage as it is rather embarassing.

W8JI made a gross error in his measurement and
then tried to rationalize the impossible result.

Well h*ll, I like him better already--then he is human, huh? ;-)

Save us from keepin' on tryn' to walk on water. chuckle

Regards,
JS

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
AI4QJ wrote:
That is his "obvious" explanation. He should remove that from his
webpage as it is rather embarassing.

W8JI made a gross error in his measurement and
then tried to rationalize the impossible result.

Cecil:

How would you have like to be working at NASA, with this group; And, you
were the one responsible for not coverting kilometers to miles and
SMACKING that spacecraft we lost into Mars? ;-)

Crud, I've volunteered on serving on those soup-lines, would hate to
have seen ya' there. chuckle

Regards,
JS

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
Tom Donaly wrote:
What is the characteristic impedance of Tom's coil?

A few thousand ohms. Use equation 50 at:

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf

What's your formula for the velocity factor of Tom's coil? Is it from
the same Tesla coil crackpot you quoted in previous posts?

Do you reject all IEEE white papers? The formula
is equation 32.

That's what I thought. Nice try, Cecil.
73,
Tom Donaly, KA6RUH

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
You and Art seem intent on collecting on a bet, or a debt, or
otherwise mooching validation, because if you two had such
dead-to-rights positions, they wouldn't require exhumation from the
grave to prop the corpses on soap box pedestals as resurrected proof.

On the contrary, Richard, old wives' tales sometimes
die hard. It's like water wearing away a stone.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
Tom Donaly wrote:
What is the characteristic impedance of Tom's coil?

A few thousand ohms. Use equation 50 at:

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf

What's your formula for the velocity factor of Tom's coil? Is it from
the same Tesla coil crackpot you quoted in previous posts?

Do you reject all IEEE white papers? The formula
is equation 32.

Cecil,

Have you actually read and understood that article? Corum mentions
several times that everything he reduces to the simple formulas applies
only to quarter-wave resonance conditions.

Look at the author's highlight between equations 31 and 32. Look at the
discussion near equation 47. Look at the discussion following equation
60. Read the entire discussion in section 5.

Note that he does not say the characteristic impedance is a constant
that can be deduced from resonance conditions and then applied to
operating conditions. In fact, he says exactly the opposite.

"It is worth noting that, for a helical anisotropic wave guide, the
effective characteristic impedance is not merely a function of the
geometrical configuration of the conductors (as it would be for lossless
TEM coaxial cables and twin-lead transmission lines), but it is also a
function of the excitation frequency."

I have no comment on the validity of the Corum analysis. He makes a lot
of approximations and simplifications which may or may not be completely
correct. However, it is clear that you are mis-quoting him.


73,
Gene
W4SZ

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
I see Cecil's temporarily run out of steam on his alternative theories
of transmission line operation and so has fallen back to his equally
imaginative pseudo-science of loading coils. I made and posted careful
measurements on this group long ago of a physically small coil to refute
some of the stranger claims being made.

Well, the subject was 75m bugcatcher loading coils", so your
choice of a "physically small coil" was already somewhat of
a straw man.

And Roy, you made the same mental blunder in your measurements
that Tom made. I have explained it to you before and you have
so far refused to listen or even read my postings so here it
is once again. Everyone is invited to think about what I am
saying and agree or attempt to refute it. Point by point:

A 1/4WL monopole over ground is known to be 90 degrees long.
The phase of the current changes by only a few degrees from
feedpoint to tip. How much phase shift (delay) in the current
would we measure in 30 degrees of a monopole? Answer: Only
one or two degrees. Why is there only a small number of degrees
of phase shift (delay) in the current in 30 degrees of monopole?
Because it is *standing-wave current* that is being used for
the measurement and the phase barely changes over the entire
monopole length.

EZNEC agrees. A 1/4WL monopole has 5.67 degrees of phase shift
in the current from segment 1 to segment 33 even though the
antenna is 90 degrees long and therefore has an inherent delay
of 90 degrees from feedpoint to tip. Standing-wave current
cannot be used to measure the delay through a wire.

So can that same *standing-wave current* be used to measure
the phase shift (delay) through a coil? Answer: No, standing
wave current cannot be used to measure the phase shift (delay)
through a wire or through a coil because the phase hardly
changes no matter how long is the delay through the coil or
through the wire (assuming coil and wire are 1/2WL).

Roy and Tom both used standing-wave current to try to measure
the delay through a coil. Such an attempt is doomed to failure
for obvious reasons and is a violation of the scientific method.

STANDING WAVE CURRENT CANNOT BE USED TO MEASURE PHASE SHIFTS
IN A WIRE OR IN A COIL BECAUSE STANDING WAVE CURRENT HAS
ESSENTIALLY NO PHASE SHIFT! THERE IS NO PHASE INFORMATION
IN STANDING WAVES!

There is absolutely no correlation between the phase of
standing-wave current and the delay through a coil or
through a wire.

What is the phase shift through a coil at self-resonance?
Answer: It is known to be 90 degrees at the first self-
resonant frequency, i.e. 180 degrees end-to-end.

What is the measured phase shift through that self-resonant
coil at the self-resonant frequency using standing-wave
current? Answer: That measured phase shift will be very
close to zero, nowhere near the known 90 degrees.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

John Smith wrote:
Cecil Moore wrote:
AI4QJ wrote:
That is his "obvious" explanation. He should remove that from his
webpage as it is rather embarassing.

W8JI made a gross error in his measurement and
then tried to rationalize the impossible result.

Well h*ll, I like him better already--then he is human, huh? ;-)
Save us from keepin' on tryn' to walk on water. chuckle

99+% of W8JI's stuff is accurate and that's great. I'm
talking about the small portion he presents as fact that
is technically impossible. The theory of current jumping
from one end of a 75m bugcatcher loading coil to the other
is a rationalization based on a conceptual error during a
measurement. W8JI obviously doesn't understand the nature
of standing-wave current on a standing-wave antenna.

The trouble is that a guru cannot afford to admit a mistake
even though he is human.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:

...
The trouble is that a guru cannot afford to admit a mistake
even though he is human.

Although, perhaps, cryptic, that is exactly what I was inferring ...

I found it the same in institutions of higher learning--surest way to a
low grade was/is to recognize an instructors mistake(s) ...

A certain, and gifted, past instructor I had once said, "We are here to
teach you the laws and rules. It is your job, in the future, to
EFFECTIVELY break them ..." I liked him. :-)

Regards,
JS

Loading Coils; was : Vincent antenna
 

Tom Donaly wrote:
Cecil Moore wrote:
Do you reject all IEEE white papers? The formula
is equation 32.

That's what I thought. Nice try, Cecil.

Is your technique to avoid losing an argument
to reject the technical proof provided by the
other side in an IEEE white paper? Of course, you
have a right to reject technical information that
is useful to amateur radio operators but please
don't stand in the way of that learning process
being used by others.

A 3nS delay through a 2" dia, 100 turn, 10 inch
long coil at 4 MHz is impossible, Tom. I think
you know that. Coils are often used for delaying
signals, not for speeding them up.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:

W8JI's mistake was using standing wave current to try
to measure that delay.

It's not at all apparent that that was his mistake.

Even though the delay changes with frequency,
it is highly unlikely to drop from 90 degrees to 4.5
degrees in a few MHz.

Any phase delay given in degrees would of course vary as function of
angular frequency independent of any systematic effect simply by
virtue of the fact that the amount of time per period varies with
frequency while the number of degrees per period obviously do not.

Over the range of a few octaves, propagation delay on the other hand
does not vary to any significant extent as a function of frequency.
Ostensibly, it should be equal to sqrt(LC) series L, shunt C.
e.g.

http://www.rhombus-ind.com/dlcat/app1_pas.pdf

In order to either validate or invalidate claims, one must do at least
two things. First make verifyable and repeatable measurements.
Second, show how those measurements are supported by the underlying
principles, and are predicted by the associated mathematics. Without
those things, you may as well go shout it at cars.

Actually, it is an exercise in the physics of reality.
A 3nS delay through a 100 uH coil is the real "exercise
in philosophical fantasy" and obviously impossible.

The display on Tom's web page appears to be set for 100ns per
division. The delay between cursor 1 and cursor 2 is 486.43 nS, and
the position of cursor 1 appears to be arbitrarily set. The 3nS
measurement would be at ~0.3% of full scale - not normally the scale
one would employ to make such a measurement. Lacking any sort of
description of the stimulus or of the instrument, it's not clear to me
what W8JI's test unit is actually measuring. But at least he measured
something and isn't shouting at cars about it.

73, ac6xg