Current through coils
 

K7ITM wrote:
I REGULARLY model transmission lines as "lumped elements" and do NOT
"presuppose that the speed of light" through them is infinite.

I'm interested in knowing how you model a shorted quarter wavelength
stub using the lumped element model.

I REGULARLY model op amps as "lumped elements" and do NOT presuppose
that the phase shift (and therefore propagation time) through them is
infinite.

I should hope not! You would never get a signal through them. :-)

I REGULARLY model inductors as "lumped elements", and do not presuppose
that they have no resistances and capacitances parasitic to their
inductANCE.

Then you are somehow applying a patch to the lumped element model.
The basic lumped element model assumes no resistance and no
capacitance. That's how the lumped inductance-only works in EZNEC.

I find that my models very reliably predict the behaviour I actually
observe in the circuits I build. I am served very well by the models I
use.

Do you use them on 75m bugcatcher coils and obtain an incorrect
phase shift as W8JI and W7EL have done?

By the way, what's EE203?

The sophmore EE class alluded to by Dr. Corum.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

On Sat, 1 Apr 2006 12:55:51 -0600, (Richard
Harrison) wrote:

Richard Clark wrote:
"The apparent capacitance based on reported resonances and modeled
reactance is on the order of 12 -14 pF."

Have you calculated the self-capacitance of a 2in x 12in single-layer
coil for yourself?

Of course not. There have been a myriad of coils twisted through this
thread and I specifically selected the one that started this epic: the
subject of Yuri's investigation (2½" by 10").

The length to diameter ratio is 6.
H = .92
D = 5 cm

HD = 4.6 pF by the formula on page 451 of the "Radiotron Designer`s
Handbook". Course, formulas are a dime a dozen and disputed.

Hi Richard,

And by virtue of their being offered renders the dismissal of
"approaching zero" as cavalier.

And this was "Self Capacitance" and not distributed capacitance? It
seems to me that any formula for capacitance that neglects the
discussion of surface area must be a very crude estimate. Are we to
believe that a coil of
H = .92mm
D = 5 mm
wound with #44 wire has the same 4.6 pF of Self Capacitance?

I can see the dime's worth of value and the source of dispute. Perhaps
there is more commentary to be found on page 451 that resolves this
and elevates the dime's worth both.

Going further, if I take your coil and merely set the turns count to
18.4, then the coil will self resonate in the 20M band. The
capacitance you computed is not very trivial for HF.

73's
Richard Clark, KB7QHC

Current through coils
 

Cecil Moore wrote:

K7ITM wrote:

I REGULARLY model transmission lines as "lumped elements" and do NOT
"presuppose that the speed of light" through them is infinite.


I'm interested in knowing how you model a shorted quarter wavelength
stub using the lumped element model.

I REGULARLY model op amps as "lumped elements" and do NOT presuppose
that the phase shift (and therefore propagation time) through them is
infinite.


I should hope not! You would never get a signal through them. :-)

I REGULARLY model inductors as "lumped elements", and do not presuppose
that they have no resistances and capacitances parasitic to their
inductANCE.


Then you are somehow applying a patch to the lumped element model.
The basic lumped element model assumes no resistance and no
capacitance. That's how the lumped inductance-only works in EZNEC.

I find that my models very reliably predict the behaviour I actually
observe in the circuits I build. I am served very well by the models I
use.


Do you use them on 75m bugcatcher coils and obtain an incorrect
phase shift as W8JI and W7EL have done?

By the way, what's EE203?


The sophmore EE class alluded to by Dr. Corum.

Cecil, there are two Corums and they're both Tesla coil
crackpots. Secondly, Tom is right, you have to have capacitance
to somewhere or your transmission line analogy becomes mired in
absurdities. Third, it isn't enough to think something up in
your head to make a convincing theory, you have to be able to
predict behavior with it. Finally, you have to understand your
subject before you even start thinking. I'm surprised you didn't
even take the time to make a real coil and at least try to
determine its characteristics before wasting everyone's
time by starting this thread.
73,
Tom Donaly, KA6RUH

Current through coils
 

On Sat, 01 Apr 2006 19:26:42 GMT, Cecil Moore
wrote:

Do you use them on 75m bugcatcher coils and obtain an incorrect
phase shift as W8JI and W7EL have done?

All measurements done by everyone are incorrect.

Yours, by your own admission 59% in error, qualifies you for the Gold,
Silver and Bronze medals of Olympian Mistakes. We can strike some
Copper, Tin, and Lead medals, but you would scoop them up too.

Current through coils
 

Tom Donaly wrote:
Cecil, there are two Corums and they're both Tesla coil
crackpots. Secondly, Tom is right, you have to have capacitance
to somewhere or your transmission line analogy becomes mired in
absurdities.

Would you guys please stop implying falsehoods and make an
attempt to argue in good faith? I didn't say the capacitance
didn't exist. I said it was a secondary effect to the superposition
of the forward and reflected waves. That you are forced to twist
what I said speaks volumes about your argument. Why don't you feel
secure enough in your technical argument not to have to twist my
words into something I didn't say?

Third, it isn't enough to think something up in
your head to make a convincing theory, you have to be able to
predict behavior with it.

I have predicted behavior on http://www.qsl.net/w5dxp/current.htm
with text surrounding http://www.qsl.net/w5dxp/1WLDIP.GIF. That
graphic is not disembodied as you claimed. It is surrounded with
examples and text, more than enough proof for any rational person.

The current at each end of a coil obviously depends upon where it
is installed in the standing wave antenna system. Your wearing of
blinders doesn't hide that technical fact from anyone except yourself.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

Richard Clark wrote:
All measurements done by everyone are incorrect.

Yours, by your own admission 59% in error, ...

Uhhhh Richard, those weren't measurements. Those were calculated
results, using formulas out of books. The only measurements that
I have made were of 1. self-resonant frequencies within the
accuracy of an MFJ-259B and 2. standing wave phase measurements
that agree with Kraus and EZNEC. The 59% accuracy was in my
wild ass *guesses* as opposed to the 207% error in W8JI's phase
*measurements*.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

wrote:
I was complaining about him altering the coil I measured and altering
the context of what I say.

The real problem is your concept that "current is current",
implying that there is some sort of identity between all
kinds of current. Is DC current identical to RF current?
If not, your "current is current" statement is incorrect.
There are different flavors of current. DC Vs RF is just
one.

Standing wave current Vs traveling wave current is another.
That you don't see the difference between func(kx)*func(wt)
and func(kx +/- wt) is the entire problem. Why are you so
unwilling to discuss that narrow technical topic?

If you would discuss that problem, you might wind up winning
the rest of the argument but you will never know until you do.
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

On Sat, 01 Apr 2006 22:00:49 GMT, Cecil Moore
wrote:

All measurements done by everyone are incorrect.

Yours, by your own admission 59% in error, ...

Uhhhh Richard, those weren't measurements. Those were calculated
results, using formulas out of books.

The crippling legacy of Xerox research.

The only measurements that
I have made were of 1. self-resonant frequencies within the
accuracy of an MFJ-259B and 2. standing wave phase measurements

Only indeed. Now there's some challenging qualification trials for an
Olympic biathlon.

that agree with Kraus

Have you been sleeping with Kraus again?

and EZNEC.

Hmm, the same EZNEC you've impeached for accuracy? When we loop back
to the top of this post to note the 59% error derived from work
accomplished that "weren't measurements" and they agree with your
"measurements" THAT just has to be another hallmark warning sign of
bogus science - self validation.

After 17,433 posts, you certainly work hard to convince yourself. ;-)

Current through coils
 

Richard Clark wrote:
Have you been sleeping with Kraus again?

Yes, I often sleep with Kraus and Balanis. You should
try occasionally reading a reference book instead of
watching The Three Stogies. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Current through coils
 

On 31 Mar 2006 16:34:07 -0800, wrote:

[snip]

I'm sure the 800-post thread will continue another 800 posts. People
must be bored.

You've noticed :-)