On Mon, 11 May 2009 16:28:04 -0700, "Tom Donaly"
wrote:

Hi Richard,
In point of fact, I just used a dip-meter-frequency-counter
combination to see if I could get somewhere near the results that
ON4AA's calculator suggested.

Hi Tom,

I wouldn't have expected any other method based on your "tease."
It answers the need for lightly coupling which responds to your
admonition of not presenting disturbances to the measurement. About
the only variation to this would be in how you could lighten up the
coupling further. I don't see Cecil struggling for the low fruit
here, so I'm not expecting to see him make this into a rum punch.

Later, I cut the coil at its center point,
attached a cheap antenna analyzer there and looked for a frequency of
least impedance. The dip meter indicated about 8.93 Mhz and the analyzer
indicated 8.98 Mhz. I consider the closeness of the two readings to be
pure accident.

Pursuing an alternative method helps validate them both, another
hallmark of good bench work. That Steve finds two values that
correlate through software begs the question of what parameters were
used. As such, two in silicon against two at the bench - something's
got to give. The differences are not deep in the decimal places.

However, they do reinforce each other in leading me to
believe that the Corum calculator has some serious deficiencies. Serious
enough, that those who claim its correctness should do some practical
investigation into its merits in order to spare themselves the jibes of
their more analytical brethren.

Tom subscribes to Corum (if I read his posts correctly), to the extent
of his needs. That seems sufficient for me, but it does not attach a
proof to the conjectures and it doesn't serve the glaring points by
the authors that their model works only with resonating coils (if I am
reading them correctly), or unless you derive your own M factor (no
one stepping up to the plate for that suggests they have no deep
interest in the topic). They allow roughly 10% error as it stands,
and I observe debates trying to leverage 5% positions.

73's
Richard Clark, KB7QHC

K7ITM wrote:
On May 11, 2:09 pm, wrote:
Hi Richard,

I wont even attempt to answer the "intimidating" questions - they're
far too tough for me!

But just a couple of comments:

1) The change in coil size when I swapped from a base-loaded to a mid-
loaded model was nothing more than a convenience to reduce the total
number of segments and reduce the computation time. It was not borne
out of any electrical considerations, so please don't read anything
more than that into it. In retrospect it was a silly thing to do
because it has probably introduced a "red herring".

2) You suggest that the Corum method has little utility. However, the
inductance calculator based on the method appears to give usefully
accurate predictions of "equivalent lumped reactance" and SRF (jury
still out on that one). If that calculator was not available, it seems
to me that designing a coil for something like a mobile whip loading
application would require tedious iterations of the helix generator in
EZNEC.

73,
Steve G3TXQ

For what it's worth, I've been using a coil program for quite a few
years now that is able to calculate the performance of a coil based on
a helical transmission line model. It was developed out of travelling
wave tube theory. It turns out I discovered a bug in the program and
reported it to the author, who very kindly corrected it. I've come to
trust it to come up with answers that are very useful in an
engineering sense. I would not expect it to tell me inductance or
other parameters (e.g., first parallel self resonance and first series
self resonance) accurately enough to be used as a precision lab
standard, but that's not what I use the program for.

When I became aware of the HamWaves web page, I was curious about how
well its answers compared with the ones I'd become used to trusting.
They do differ a little, but again, for what I do with them, I trust
them both. Either one will provide results I can use to wind a coil
for a filter and know I won't have to much to adjust the coil to being
"right on." And in fact, I also found a very small bug (or at least
an anomaly or inconsistency) in the HamWaves calculation, and reported
that to Serge, who likewise very graciously acknowledged it and who I
believe corrected it.

So I'd strongly support your thought that the HamWaves calculator
provides useful results. Understand that they won't be perfect, but
also understand that you may have trouble making measurements accurate
enough to know how much they are in error. But for almost everything
I do with coils, what I care about is whether the filter or tank
circuit or antenna in which the coil is used actually works like I
want. My trust in these programs comes from being able to build a lot
of filters over the years that all work like I designed them to work,
with very little effort to tweak the coils I built per the programs'
predictions. I'll adjust my expectations if I ever find cases where
the programs lead me astray.

Cheers,
Tom

Hi Tom,
A testimonial from you goes a long way toward building some
trust in ON4AA's coil calculator. I was concerned because I haven't seen
much in the way of empirical data to substantiate the claims made for
it. I would have thought that the creators would have at least provided
a link to some data, or to a description of their own coil-making efforts.
73,
Tom Donaly, KA6RUH

Tom Donaly wrote:
A testimonial from you goes a long way toward building some
trust in ON4AA's coil calculator.

Testimonials do not make technical information true
or false. This technical information has been available
for the past 5-8 years.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Richard Clark wrote:
On Mon, 11 May 2009 16:28:04 -0700, "Tom Donaly"
wrote:

Hi Richard,
In point of fact, I just used a dip-meter-frequency-counter
combination to see if I could get somewhere near the results that
ON4AA's calculator suggested.

Hi Tom,

I wouldn't have expected any other method based on your "tease."
It answers the need for lightly coupling which responds to your
admonition of not presenting disturbances to the measurement. About
the only variation to this would be in how you could lighten up the
coupling further. I don't see Cecil struggling for the low fruit
here, so I'm not expecting to see him make this into a rum punch.

Later, I cut the coil at its center point,
attached a cheap antenna analyzer there and looked for a frequency of
least impedance. The dip meter indicated about 8.93 Mhz and the analyzer
indicated 8.98 Mhz. I consider the closeness of the two readings to be
pure accident.

Pursuing an alternative method helps validate them both, another
hallmark of good bench work. That Steve finds two values that
correlate through software begs the question of what parameters were
used. As such, two in silicon against two at the bench - something's
got to give. The differences are not deep in the decimal places.

However, they do reinforce each other in leading me to
believe that the Corum calculator has some serious deficiencies. Serious
enough, that those who claim its correctness should do some practical
investigation into its merits in order to spare themselves the jibes of
their more analytical brethren.

Tom subscribes to Corum (if I read his posts correctly), to the extent
of his needs. That seems sufficient for me, but it does not attach a
proof to the conjectures and it doesn't serve the glaring points by
the authors that their model works only with resonating coils (if I am
reading them correctly), or unless you derive your own M factor (no
one stepping up to the plate for that suggests they have no deep
interest in the topic). They allow roughly 10% error as it stands,
and I observe debates trying to leverage 5% positions.

73's
Richard Clark, KB7QHC

Hi Richard,
And then there is Cecil. I was hoping I could crowd him
into slapping leather over this and get him to do some experimenting.
I should have known better.
73,
Tom Donaly, KA6RUH

(P.S. Excuse the shamefully unattributed extract from Shane.)

Tom Donaly wrote:
And then there is Cecil. I was hoping I could crowd him
into slapping leather over this and get him to do some
experimenting. I should have known better.

Sorry, first things first. I am a newlywed (Feb. 28) and
all my equipment is still packed in boxes after squeezing
into a new QTH. I am presently not even on the air.
I reported my experimental results years ago and was
satisfied with the results.

Hint: My experiments do not affect (or effect)
technical facts. Neither do your beliefs or anyone's
testimonials. Those technical facts have been staring
you in the face for 5+ years now. What have you been
doing for the past 5 years - anything except ad hominem
attacks?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

On May 11, 6:29*pm, "Tom Donaly" wrote:
K7ITM wrote:
On May 11, 2:09 pm, wrote:
Hi Richard,

I wont even attempt to answer the "intimidating" questions - they're
far too tough for me!

But just a couple of comments:

1) The change in coil size when I swapped from a base-loaded to a mid-
loaded model was nothing more than a convenience to reduce the total
number of segments and reduce the computation time. It was not borne
out of any electrical considerations, so please don't read anything
more than that into it. In retrospect it was a silly thing to do
because it has probably introduced a "red herring".

2) You suggest that the Corum method has little utility. However, the
inductance calculator based on the method appears to give usefully
accurate predictions of "equivalent lumped reactance" and SRF (jury
still out on that one). If that calculator was not available, it seems
to me that designing a coil for something like a mobile whip loading
application would require tedious iterations of the helix generator in
EZNEC.

73,
Steve G3TXQ

For what it's worth, I've been using a coil program for quite a few
years now that is able to calculate the performance of a coil based on
a helical transmission line model. *It was developed out of travelling
wave tube theory. *It turns out I discovered a bug in the program and
reported it to the author, who very kindly corrected it. *I've come to
trust it to come up with answers that are very useful in an
engineering sense. *I would not expect it to tell me inductance or
other parameters (e.g., first parallel self resonance and first series
self resonance) accurately enough to be used as a precision lab
standard, but that's not what I use the program for.

When I became aware of the HamWaves web page, I was curious about how
well its answers compared with the ones I'd become used to trusting.
They do differ a little, but again, for what I do with them, I trust
them both. *Either one will provide results I can use to wind a coil
for a filter and know I won't have to much to adjust the coil to being
"right on." *And in fact, I also found a very small bug (or at least
an anomaly or inconsistency) in the HamWaves calculation, and reported
that to Serge, who likewise very graciously acknowledged it and who I
believe corrected it.

So I'd strongly support your thought that the HamWaves calculator
provides useful results. *Understand that they won't be perfect, but
also understand that you may have trouble making measurements accurate
enough to know how much they are in error. *But for almost everything
I do with coils, what I care about is whether the filter or tank
circuit or antenna in which the coil is used actually works like I
want. *My trust in these programs comes from being able to build a lot
of filters over the years that all work like I designed them to work,
with very little effort to tweak the coils I built per the programs'
predictions. *I'll adjust my expectations if I ever find cases where
the programs lead me astray.

Cheers,
Tom

Hi Tom,
* * * * *A testimonial from you goes a long way toward building some
trust in ON4AA's coil calculator. I was concerned because I haven't seen
much in the way of empirical data to substantiate the claims made for
it. I would have thought that the creators would have at least provided
a link to some data, or to a description of their own coil-making efforts..
73,
Tom Donaly, KA6RUH

Well, I'm flattered, but I'd invite you and anyone else here who might
build coils for practical purposes to report back how that calculator,
or any other, worked for them. The homebrew newsgroup might be a
better place to do that. And if you think you've come up with a
situation where any calculator seems significantly in error, don't be
shy about reporting it to the author or maintainer of the calculator.
I've found most to be quite happy to hear about bugs, especially if
they are well documented, if they are told in a nice way.

I tend to not push the limits on coil calculations, because I know
that I'll get the best volumetric efficiencies with coils over a
relatively small range of diameter-to-length ratios, and for air-core
solenoid RF coils used between a couple MHz and a few hundred MHz, I
know what physical size I'll need for any particular required Qu. So
you very well may find cases of more extreme D:L ratios where a
calculator I've learned to trust isn't so hot -- and honestly, I'd
love to know about such limits.

Cheers,
Tom


Cheers,
Tom

Richard Clark wrote:

That's OK. Even the Corums didn't answer them and it accounts for the
rather thin material being leveraged into the new-age science we get
discussed here.


Giving rise to the phrase, "Lack of De-corum".

(cymbal crash)


- Just catching up here...... 73 de Mike N3LI -

Cecil Moore wrote:

Sorry, first things first. I am a newlywed (Feb. 28) and
all my equipment is still packed in boxes after squeezing
into a new QTH.


Congratulations on the recent nuptials, Cecil, My regards to the new Mrs
Moore.

- 73 de Mike N3LI -

"Richard Harrison" wrote
...
Art wrote:
"Thus Kraus`s antennas are not in equilibrium and thus deviated away
from Maxwell`s laws."

Impossible.

Maxwell`s laws are all that is nscessary and sufficient to describe
radiation from any antenna.

On page 37 of Kraus & Marthelka`s "Antennas for All Applications" one
can read:

"Although a charge moving with uniform velocity along a sreaighr
conductor does not radiate, a charge moving back and forth in simple
harmonic motion along the conductor is subject to aceleration (and
deceleration) and radiates."

Tell us than from which part of Hertz apparatus a radio waves are radiated?
(http://people.seas.harvard.edu/~jone...Hertz_exp.html

Are they transverse or longitudinal?
S*

"Dave Platt" wrote
...
Art Unwin wrote:
I don't know about waves but my understanding is that all colors come
from the mixing of the three basic colors, or is it four?

Your understanding is in error... at least, if you're referring to
colors in terms of actual photon behavior (energy and wavelength)
rather than to the human *perception* of color.

That's the RGB standard designed for fooling human
eyes into seeing more than just red, green, and blue.

Yup. And, the red/green/blue system is an artifact of the human
visual system... most of us happen to have three different types
of photo-sensitive molecules in the cone cells in our eyes, and these
three types of molecules have their peak receptivities at the
frequencies that we refer to as "red", "green", and "blue."

There seems to be some amount of genetic variation, among humans, in
the exact frequencies at which the peak sensitivies lie. And, some
people have are missing one or more of these types of photoreceptor,
and are referred to as "colorblind".

There are apparently some humans who have four different types of
photopigment, and thus may have an improved ability to perceive
distinctions between colors. Certain species of animal are known to
have four photopigments (one for e.g. UV sensitivity) and I wouldn't
be surprised if some species have five or more variants.

Photons in nature come in *all* EM frequencies.

Yup again. It's an interesting process:

- Light comes in a continuous range of frequencies.

- Our eyes "sample" this continous range, with three types of sensor
having different-but-overlapping sensitivities. Each sensor
generates a variable amplitude (or pulse train) based on the
intensity that it's detecting, within its sensitivity range.

- Our nervous system maps the three amplitudes back into a perception
of a continuous range of colors.

The process is far from perfect... information is lost during the
sampling process, and thus the perception of a continuous spectrum is
necessarily flawed and imperfect.

This is why a mixture of two different pure colors (e.g. red and
green) can look like a single pure color to our eyes (e.g. yellow or
amber)... it happens to excite the red and green photosensors in the
same proportion that a single, pure-yellow light would. Mixed
together, the colors look like one... split them apart with a prism
and you can easily distinguish them and see the trick.

Sometimes the screen on TV or cinema is perfectly white. This in cinema
reflect. This reflected light splitted with the prism has only three
frequences?

[Almost] All Is Illusion.
S*