Current through coils
 

On Wed, 08 Mar 2006 01:46:19 GMT, Cecil Moore wrote:

wrote:
All personal issues and insults aside, before anyone does anything with
any of this they would have to have a good feel for how an inductor
behaves.

I just asked my dog if she has a good feeling about how an inductor
behaves. She wagged her tail in affirmation. ...

Oh no Cecil, not another citation!

Owen
--

Current through coils
 

Hey folks, they have a word that's used occasionally that I think might
be appropriate here, it is "chill".

As in chill out.

Things are getting more out of hand than normal.

Some of you are adults, please start acting that way.

Some people have been trying, possibly poorly, to be funny, forgive them.

I could say more, but you get the idea.

tom
K0TAR

Current through coils
 

Tom Ring wrote:
Some of you are adults, please start acting that way.

Tom, I apologize profusely to everyone for losing my temper.
I regret that every time it happens but that time never seems
to be the final time. I canceled my posting made in anger. But
please note that me losing my temper has absolutely no bearing
on objective technical facts and has absolutely no effect at
all on the validity of my technical arguments. Galileo probably
lost his temper in front of the priests who placed him under
house arrest. That made absolutely no difference in the
scientific facts that he was asserting at the time.

I am presenting my thoughts in front of the internet gurus
in much the same manner as Galileo did to the priests. Hopefully,
they will listen better than the priests did and not put me under
house arrest. (But I have my Colt 45 ready just in case. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

wrote:
That doesn't sound like Walter gave you permission to me.

I have backtracked to try to find out what happened. I asked
Walt's permission to post the following:

Walter Maxwell wrote:
If an inductance is in series with a line that has no reflections,
the current will be the same at both ends of the inductor.

If an inductance is in series with a line that has reflections,
the current will NOT be the same at both ends of the inductor.

Consequently, circuit analysis will not work when both forward
and reflected currents are present in a lumped circuit.

He agreed but suggested I also include his fourth statement which
followed the above three statements.

When reflections are present, a current node and a current loop
can appear at separate points on an inductor simultaneously.

When I went back to copy and paste bottom-up from his email
in order to include his fourth assertion, I inadvertently copied
one too many sentences at the top. It is true that I didn't have
Walt's permission to publish that extra first sentence in his email.
I regret that accidental mistake and wish I could take it back.
And of course, neither Walt nor anyone else in the universe agrees
with me 100%.

But please note that accidentally including that first sentence doesn't
change the technical content of Walt's other four assertions which should
be allowed to stand as is until further notice.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

On Wed, 08 Mar 2006 00:29:14 GMT, Cecil Moore wrote:

Walter Maxwell earlier wrote:

By accounts, Walt works both sides of the street for them.

This Hustle & Flow of posts redefines the Academy award to
"It's Hard Out Here for the Pimps"

Current through coils
 

Do you agree or disagree with my post about how an inductor behaves?

I disagree with you about how an inductor behaves in a standing
wave environment. I agree with Walter Maxwell who said:
"If an inductance is in series with a line that has reflections, the
current will NOT be the same at both ends of the inductor."

Then we can't go further with this Cecil, unless you can accurately
explain WHY the behavior of an inductor changes when it is in an
antenna, rather than in some other system where impedances are the same
or very similar. It seems that Ian, Reg, Roy, and several others
including myself all believe an inductor works the same way. If you
convince one of us we are in error the others will surely follow!

If you refuse to discuss the behavior or electrical characteristics of
the component you are talking about, there really isn't anything we can
talk about. In that case I suggest you leave my name out of things, and
I'll do the same for you.

When you are ready to talk about the root problem, I'll try to be here.

73 Tom

Current through coils
 

wrote:

Do you agree or disagree with my post about how an inductor behaves?

I disagree with you about how an inductor behaves in a standing
wave environment. I agree with Walter Maxwell who said:
"If an inductance is in series with a line that has reflections, the
current will NOT be the same at both ends of the inductor."

Then we can't go further with this Cecil, unless you can accurately
explain WHY the behavior of an inductor changes when it is in an
antenna, rather than in some other system where impedances are the same
or very similar. It seems that Ian, Reg, Roy, and several others
including myself all believe an inductor works the same way.

And also, if the inductively loaded antenna is designed by the "antenna
as transmission line" method (as used by Boyer and ON4UN for example) it
clearly shows that the loading inductance is simply there to cancel the
net capacitive reactance - in other words, it behaves in exactly the
same way as you would in any other circuit.

The irony is that Boyer *does* use the concept of reflected traveling
waves in his basic explanation of how monopole antennas work. The
difference is that he understood how to do it without tying himself in
knots.

'Antenna Transmission Line Analog: a key to understanding antennas' by
Joseph M Boyer (W6UYH, SK 1988). Ham Radio, April 1977 and May 1977.


If you
convince one of us we are in error the others will surely follow!

Slip of the fingers there, Tom - there aren't any "followers" in that
particular company. We are all fiercely independent-minded individuals,
absolutely determined to do our own thinking and to get it right.

It is true that we agree on a lot of things, but there's only one reason
for that: because physical reality is the same in Oregon, England and
Scotland as it is in Georgia. There is a very high probability that it's
the same in Texas too.



--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Current through coils
 

On Wed, 8 Mar 2006 11:41:38 +0000, Ian White GM3SEK
wrote:

[snip]

It is true that we agree on a lot of things, but there's only one reason
for that: because physical reality is the same in Oregon, England and
Scotland as it is in Georgia. There is a very high probability that it's
the same in Texas too.

Careful Ian, remember that our President calls Texas home, so the
probability might not be so high after all. ;-)

ps. I crossed paths with Joe Boyer a couple of times when we were
both at Hughes.

Current through coils
 

wrote:
Then we can't go further with this Cecil, ...

That's simply not true. We can take this discussion to its
logical conclusion if you are not afraid to continue it in
logical order at a logical starting point.

Starting with coils is like looking for your keys under the
street light, instead of where you lost them, because that's
where the light is better.

Coil theory is not the problem. Standing wave current theory
is the problem. Let's discuss the problem.

If you refuse to discuss the behavior or electrical characteristics of
the component you are talking about, there really isn't anything we can
talk about.

I'm not refusing to discuss anything as long as it is taken
in logical order. Our disagreement extends much farther back
into fundamental technical principles than just the subject of
coil function. We actually may have no technical disagreement
about coils. I believe our basic disagreement involves standing
wave current, not coils, so standing wave current should be the
topic of this initial discussion. For that, we need to first
agree on the 1/2WL thin wire model of a dipole.

Let's see what we can agree on. Can we agree on the following
pertaining to a 1/2 wavelength thin wire dipole?

The net current in a standing wave antenna is a standing wave.
The net current displayed by EZNEC for a standing wave antenna
is a standing wave. The net standing wave current is the phasor
sum of the forward current traveling wave and the reflected
current traveling wave. The principle of superposition applies
to the two component waves. If we superpose the forward current
traveling wave and the reflected current traveling wave, we
obtain the net standing wave current.

Let's take for instance, that 1/2WL thin wire dipole. The standing
wave current distribution and phase appears in Figure 14-2 in
Kraus and Figures 1.15 and 4.8 in Balanis. If the current at the
feedpoint is 1 amp, the net standing wave current equals cosine(x)
where 'x' is the distance in degrees away from the feedpoint.

This topic of discussion will most likely reveal that our fundamental
point of disagreement is standing wave current and not coils at all.
So which points above do you agree/disagree with?

References to Kraus are from "Antennas for All Applications",
Kraus and Marhefka, 3rd edition.

References to Balanis are from "Antenna Theory", Balanis,
2nd edition.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Ian White GM3SEK wrote:
And also, if the inductively loaded antenna is designed by the "antenna
as transmission line" method (as used by Boyer and ON4UN for example) it
clearly shows that the loading inductance is simply there to cancel the
net capacitive reactance - in other words, it behaves in exactly the
same way as you would in any other circuit.

If that is true, you guys shouldn't have any difficulty proving me wrong
and sending me back to the woodshed once and for all. If the above is not
entirely true, please don't put me under house arrest until I present the
truth as I see it. And certainly, call me on anything that is wrong.

If you will keep listening with an open mind, I think I can show you
that the words, "clearly", "simply", and "exactly", in your above
statement are not entirely correct.
--
Ian, no one has explained the antenna currents reported by EZNEC at:

http://www.qsl.net/w5dxp/qrzgif35.gif

How can 0.1+ amp of current be 'flowing' into the bottom of the coil
and 0.7+ amp of current be 'flowing' out of the top of the coil. It's
been days now and no one has offered an explanation.
--
73, Cecil http://www.qsl.net/w5dxp