Gene Fuller wrote:

Cecil Moore wrote:
A 75m bugcatcher coil is self resonant at 6.6 MHz. That's
near 4 MHz. Where is all your irrationality coming from?

The exact quote from your message on April 11, at 9:57 am is copied
below. I don't see anything about a bugcatcher coil.

The coil being discussed is a bugcatcher coil modeled in EZNEC.

Since the Corum paper highlighted the limitation for applicability of
the magic formula it is possible he thought that the limitation might be
important.

The limitation that Dr. Corum highlighted was the failure of the
lumped circuit model when the coil is self-resonant. He says that
when we are within 17% of self-resonance, the lumped circuit model
fails. Have you anything besides faith to prove that your model
is valid within 60% of self-resonance?

Please describe the physics behind a radical change in velocity
factor (at the same frequency) when a coil is cut in half.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
Gene Fuller wrote:

Cecil Moore wrote:
A 75m bugcatcher coil is self resonant at 6.6 MHz. That's
near 4 MHz. Where is all your irrationality coming from?

The exact quote from your message on April 11, at 9:57 am is copied
below. I don't see anything about a bugcatcher coil.


The coil being discussed is a bugcatcher coil modeled in EZNEC.

Since the Corum paper highlighted the limitation for applicability of
the magic formula it is possible he thought that the limitation might
be important.


The limitation that Dr. Corum highlighted was the failure of the
lumped circuit model when the coil is self-resonant. He says that
when we are within 17% of self-resonance, the lumped circuit model
fails. Have you anything besides faith to prove that your model
is valid within 60% of self-resonance?

Please describe the physics behind a radical change in velocity
factor (at the same frequency) when a coil is cut in half.

Cecil,

You have really lost it. I gave you the exact quote, and you then
proceed to talk about something else.

It appears you did not really read and understand the Corum paper
either. The portion I referred to you had nothing to say about lumped
circuits or distributed circuits. It was merely a step in the
mathematical analysis that leads to the magic formula for Vf. If you
ignore the important limitations on the math analysis it is likely that
any conclusions drawn will be incorrect.

So let's throw the topic back to you. A straight wire has a Vf near 1. A
resonant coil has a Vf of 0.01 or 0.02. So where and how does the Vf
transition occur? For a coil of one turn? For a coil with a length of
15% of the resonant length? At some other coil length? Is the Vf
transition abrupt or smooth?

You seem to understand everything about coil Vf, so these should be easy
questions for you.

73,
Gene
W4SZ

Gene Fuller wrote:
You have really lost it. I gave you the exact quote, and you then
proceed to talk about something else.

Your quote doesn't mean what you think it means. The velocity
factor equation is appropriate for quarterwave resonance *and*
any other length at the same frequency. The graph in the next
column over shows coils of 10,000 turns per wavelength. It does
NOT limit them to any length so your argument is bogus.

Their goal was to find a VF equation that worked for quarterwave
resonance but it works for a lot more than quarterwave resonance.
It holds for any length as can be seen from Fig. 1.

So let's throw the topic back to you.

Too late, I asked you first. Where are the laws of physics
to back up your assertions? Certainly not contained in the
Corum papers. Please provide some reference that asserts
that the VF of a coil varies with its length while keeping
all other parameters constant.

The coil being modeled is 48 turns per foot. The wavelength
is 246 feet. 48*246 = 11,808 turns per wavelength. That's
on the Corum chart. There is NO minimum or maximum length
requirement or constraint. According to the paper, the velocity
factor is within 10% no matter what the length of the coil.

So holding all the variables constant in the velocity factor
equation and changing only the length is a valid way to
calculate the approximate delay through the coil. It's the
best way that we have so far. It is infinitely better than
using a signal with unchanging phase to try to measure
phase shift.

So where and how does the Vf transition occur?

Just as in a transmission line, a VF transition occurs
at an impedance discontinuity. For a complete helical
antenna, there is no impedance discontinuity. For an
antenna containing a coil and wire, there is an impedance
discontinuity at the coil/wire interface.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil,

The "quote" was from your message, not the Corum paper. It is highly
likely that it does not mean what I think it means. It probably does not
even mean the same thing to you after a few minutes.

As for the Corum paper, would you be so kind as to point out the page
where it is written:

The velocity factor equation is appropriate for quarterwave resonance
*and* any other length at the same frequency.

I found the section that says the formula is appropriate at resonance,
and I must have missed the part that says the formula works for any
length as long as the frequency is maintained.

You still have not explained at what point the transition from Vf ~ 1 to
Vf 0.02 occurs.


73,
Gene
W4SZ


Cecil Moore wrote:
Gene Fuller wrote:

You have really lost it. I gave you the exact quote, and you then
proceed to talk about something else.


Your quote doesn't mean what you think it means. The velocity
factor equation is appropriate for quarterwave resonance *and*
any other length at the same frequency. The graph in the next
column over shows coils of 10,000 turns per wavelength. It does
NOT limit them to any length so your argument is bogus.

Their goal was to find a VF equation that worked for quarterwave
resonance but it works for a lot more than quarterwave resonance.
It holds for any length as can be seen from Fig. 1.

Gene Fuller wrote:
As for the Corum paper, would you be so kind as to point out the page
where it is written:

The velocity factor equation is appropriate for quarterwave resonance
*and* any other length at the same frequency.

I already told you - same page, Fig. 1 where that VF equation is
plotted. There is absolutely no reference to coil length in Fig. 1.
The only independent variables are the diameter/wavelength ratio
and the turns/wavelength ratio. For any length coil with the above
fixed parameters, including frequency, the VF is constant within
10%.

I found the section that says the formula is appropriate at resonance,
and I must have missed the part that says the formula works for any
length as long as the frequency is maintained.

"We have found that this expression gives acceptable results (errors
less than 10%) for most practical applications that involve wave
propagation on helical resonators ..." Absolutely no mention of
14WL self-resonance.

You still have not explained at what point the transition from Vf ~ 1 to
Vf 0.02 occurs.

It is explained perfectly in Fig. 1 where the VF scale goes from
0.0 to 1.0. Come over to my house for a beer and I will teach you
how to read that graph.

Exactly as would be expected, holding the diameter/wavelength ratio
constant, as the helical is wound tighter and tighter, the VF decreases.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:


"We have found that this expression gives acceptable results (errors
less than 10%) for most practical applications that involve wave
propagation on helical resonators ..." Absolutely no mention of
14WL self-resonance.

Cecil,

Oh darn! There's that nasty reference to "resonator" again. You really
need to read the paper again and attempt to understand it.

Try the left-hand column on the page for the fundamental mathematical
limitation that underlies everything else on the page, including Figure 1.

Since this is a question of literacy and not technology there is little
more to be said here.

73,
Gene
W4SZ

On Wed, 19 Apr 2006 23:32:53 GMT, Gene Fuller
wrote:

Oh darn! There's that nasty reference to "resonator" again.

Resonant [6], resonance [11], resonator (the title of the paper)[24]
are littered throughout so frequently [41 times in 10 pages] that you
would have to get a dispensation from the pope to talk about pure
resistance.

Cecil Moore wrote:
"We have found that this expression gives acceptable results (errors
less than 10%) for most practical applications that involve wave
propagation on helical resonators ..." Absolutely no mention of
14WL self-resonance.

Gene Fuller wrote:
Oh darn! There's that nasty reference to "resonator" again. You really
need to read the paper again and attempt to understand it.

Try the left-hand column on the page for the fundamental mathematical
limitation that underlies everything else on the page, including Figure 1.

Since this is a question of literacy and not technology there is little
more to be said here.

Gene,

I can't believe you are still trying to get Cecil to actually read the
paper he is misquoting.
I've seen his debating style before. It's the last man standing wins,
no matter how obviously wrong he is. You'll never win that kind of
debate with logic or science Gene.

Never.

73 Tom

Gene Fuller wrote:
Oh darn! There's that nasty reference to "resonator" again. You really
need to read the paper again and attempt to understand it.

Uhhhhh Gene, a 75m bugcatcher coil is a "resonator" that
resonates an 8 foot mobile antenna on 75m. Take a look at
Figure 2 in Dr. Corum's paper. It looks just like a top-
loaded 160m mobile antenna.

Try the left-hand column on the page for the fundamental mathematical
limitation that underlies everything else on the page, including Figure 1.

There is a test equation to see if a particular coil is
outside the fundamental mathematicdal limitations. A 75m
bugcatcher coil is less than half the limit value.

Let me show you how to use Fig. 1. The coil that we have
been discussing is 6 inches in diameter and has 4 turns
per inch. That makes D/lamda = 2.0 x 10^3. That's just
about in the middle of the graphic. The turns per wavelength
is 48*246 = 11,808. That's just to the left of the left
hand curve. Reading the velocity factor from the graph
gives about 0.03 for that coil. It's a piece of cake
if you understand the physics involved.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote in message
. com...
Gene Fuller wrote:

Cecil Moore wrote:
A 75m bugcatcher coil is self resonant at 6.6 MHz. That's
near 4 MHz. Where is all your irrationality coming from?

The exact quote from your message on April 11, at 9:57 am is
copied
below. I don't see anything about a bugcatcher coil.

The coil being discussed is a bugcatcher coil modeled in EZNEC.

Since the Corum paper highlighted the limitation for applicability
of
the magic formula it is possible he thought that the limitation
might be
important.

The limitation that Dr. Corum highlighted was the failure of the
lumped circuit model when the coil is self-resonant. He says that
when we are within 17% of self-resonance, the lumped circuit model
fails. Have you anything besides faith to prove that your model
is valid within 60% of self-resonance?

Please describe the physics behind a radical change in velocity
factor (at the same frequency) when a coil is cut in half.
--
========================================
Dear Cec,

What is the failure mode?
Is it a sudden catastropic failure?
Or does it fail very slowly, gradually and gently?

What is Dr.Corum a doctor of?

From your quotes he sounds like a Quack. Or is he a Witch?

What does he have to say about Fractals, E-H and the other wierd
contraptions?

How many other worshipping followers does he have besides yourself?

Or are you just pulling our varicose-veined legs?

All rhetorical questions of course. Answers not required.
----
Your old, well-intentioned pal, Reg.