Cecil,

I did not say anything about W8JI's measurements. He had a completely
different setup, and I had nothing to do with it.

You have a remarkable Teflon coating. I completely called your bluff on
the bugcatcher coil, and you simply ignore the result and slide away to
some other Don Quixote adventure. I am not really surprised, of course.

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

The bugcatcher example I sent you showed a phase shift of about 7
degrees at 4 MHz.


I've been waiting for you to come back with the facts that
contradict W8JI's measurements. Thanks once again.

The coil has about half the inductance of the 100 uH coil
measured by W8JI. He measured ~4 degrees in 100 uH. EZNEC
reports 8 degrees in 60 uH for an 8.5 foot antenna.

My wild ass guess was at least five times more accurate
than W8JI's measurements. Thanks for pointing that out.

Gene Fuller wrote:
I completely called your bluff on
the bugcatcher coil, and you simply ignore the result and slide away to
some other Don Quixote adventure.

The EZNEC simulation is just one more data point in a large set
of data points that are already widely scattered. EZNEC does not
have magic or God-like properties to override reality especially
when your design results in pages and pages of segmentation
guideline violations. The jury is still out on the question.

You guys have a habit of declaring victory when you score your
first point after trailing 10-0. When only one coil out of a
dozen tests showed the current at each end of the toroidal
coil to be the same, W8JI declared that was proof that all
coils have the same current at each end.

If you will check my postings, you will see that I said
the delay through a coil is what it is and we usually don't
know what it is. But we do know it is NOT instantaneous and
we know it is unlikely to be the 3 nS measured by W8JI.

I was surprised to see EZNEC report the delay as 20% less than
my lower estimate of 10 degrees. But that 8 degrees is 100%
higher than W8JI's measured values.

And there's your pesky posting about standing wave currents.

The only "phase" remaining is the cos (kz) term, which is really an amplitude
description, not a phase.

If we assume the 1.013 amp at the bottom of the coil occurs when
the forward and reflected currents are in phase, then the 0.7628
amps at the top of the coil would have the currents 82 degrees
out of phase, i.e. a 41 degree phase shift through the coil.
That is, of course, only a rough estimate, but enough different
from the 8 degrees to suspect something is wrong with my suggested
traveling wave antenna.
--
73, Cecil http://www.qsl.net/w5dxp

"Gene Fuller" wrote:
I did not say anything about W8JI's measurements. He had a completely
different setup, and I had nothing to do with it.

Didn't say you did and it's good that the two were unrelated -
just wanted to point out the contradictions between your
EZNEC results and W8JI's 3 nS measurements.

I have uncovered a slight conceptual error in my traveling wave
antenna simulation. I took care to eliminate reflections between
the top of the coil and the load on the traveling wave wire. But
I didn't do anything to eliminate reflections from the bottom of
the coil. So the current phase at the load at the bottom of the
coil is not from a traveling wave. It is instead from a standing
wave or a combination of the two waves.

The bottom section is one foot long. Knowing the frequency,
e.g. 4 MHz, allows us to calculate the delay in that one foot
of wire, i.e. 0.0041 WL = 1.5 degrees. So the current
phase at the bottom of the coil is -1.5 degrees on 4 MHz.
With the current phase at the top of the coil being 10.72
degrees, that gives a phase shift through the coil of
9.22 degrees which is equivalent to 6.4 nS, more than
double W8JI's measured value still posted to his web page.
--
73, Cecil, W5DXP

Cec, do you think that knowledge of reflected waves and phase angles
and propagation delays will enable an antenna designer to construct
something that will win contests every time? ;o)

I'd rather place my confidence in screwing an extra length on the top
end of the loaded whip and damn the extra propagation delay.

I nearly didn't post this.
----
Reg

Cecil,

The numbers you quote below have no relationship to the numbers from the
model I sent you. This is the third time you have "accidentally" screwed
with the model.

73,
Gene
W4SZ

Cecil Moore wrote:


The bottom section is one foot long. Knowing the frequency,
e.g. 4 MHz, allows us to calculate the delay in that one foot
of wire, i.e. 0.0041 WL = 1.5 degrees. So the current
phase at the bottom of the coil is -1.5 degrees on 4 MHz.
With the current phase at the top of the coil being 10.72
degrees, that gives a phase shift through the coil of
9.22 degrees which is equivalent to 6.4 nS, more than
double W8JI's measured value still posted to his web page.
--
73, Cecil, W5DXP

Gene Fuller wrote:
The numbers you quote below have no relationship to the numbers from the
model I sent you. This is the third time you have "accidentally" screwed
with the model.

It was no accident. Those numbers are from your model modified
to an 8.5 ft. tall antenna. *Our original agreement was an 8 ft.
tall antenna.* Your antenna was almost 50% longer, and that was a
violation of the agreed upon boundary conditions. If you made
it 50 feet tall the delay through the coil would be even smaller.
I'll send you the modified files.
--
73, Cecil http://www.qsl.net/w5dxp