Loading Coils; was : Vincent antenna
 

Tom Donaly wrote:
Yes, but not using it very well, or you would have been
able to answer the math problem I posed to you.

I'm sorry, Tom, I didn't even read the math problem
you posed to me as I don't have time for it right
now. I'm sure anyone could use the distributed
network model to solve your problem, even you.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Keith Dysart wrote:
But then why not take the opportunity to learn?
Instead of arguing from a point which you now
claim was ignorance.

Sorry, I didn't do that. My only point was that
one could indeed track the energy in the amplifier
if one understand where the destructive interference
is vs where the constructive interference is. Every-
thing I said is based on the conservation of energy,
not on the design of the amplifier.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Ian White GM3SEK wrote:
Cecil Moore wrote:
Ian White GM3SEK wrote:
Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Really???? Just try your lumped inductance model on
a helical antenna and get back to us.

Yet more stinking dishonest quoting from Cecil. What I ACTUALLY wrote was:

"Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Yep, that's exactly as I quoted it.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

On Dec 8, 3:15 pm, "AI4QJ" wrote:
"Gene Fuller" wrote in message

...





Cecil Moore wrote:

---43.4 deg 600 ohm line---+---10 deg 100 ohm line---open

The Smith Chart does make it clear what is happening.
Here is the math to go with it. The impedance at the
junction of the two lines is:

-j100*tan(90-10) = -j100*tan(80) = -j567 ohms
-j600*tan(43.4) = -j600*tan(43.4) = -j567 ohms

The phase shift at the junction of the two lines is:
80-43.4 = 36.6 degrees

Time permitting, I will work up the phasor diagrams of
the component voltages (or currents) at the junction
where rho = (600-100)/(600+100) = 0.7143

So how many nanoseconds does that 36.6 degree phase shift represent?

8-)

In this example, we have transmission lines, not an antenna or antenna coil.
The total phase shift is 90 degrees or 62.5 nsec.

Only with great stretching.

The 10 degree 100 ohm line contributes 6.94nsec,

Correct.

the 43 degree 600 ohm line contributes 29.86 nsec.

Correct.

But now think in the time domain for a bit.
29.86 nsec after the signal is first applied it reaches the
discontinuity. 29.86 nsec later the first reflection arrives
back at the start. 13.8 nsec later the first reflection from
the end of the 100 ohm section arrives back at the start.
It takes many more reflections of reflections before the
impedance at the input starts to look like a short.

Nowhere in here will you be able to find anything that
happens in 62.5 nsec.

This is quite unlike an actual physical 1/4WL stub
where the first reflection does arrive back in
2 * 62.5 nsec. And the impedance at the input
behaves like a short after exactly 125 nsec.

Of course the ultimate is an actual short, where
Cecil's 90 degrees happens immediately.

These 90 degrees that Cecil insists are "always"
present are quite difficult to locate.

....Keith

Loading Coils; was : Vincent antenna
 

John Smith wrote:
Dave Heil wrote:

...
Which comments, "John"? You snipped everything I wrote.

Dave K8MN

That would be impossible for me to do; Look at your post, which "that
post" of mine responded to, all of your text is still there ...

Are you agog in Google World, "John"? There is no way of telling which
of my posts you responded to. My material was not quoted.

Dave K8MN

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
Tom Donaly wrote:
Yes, but not using it very well, or you would have been
able to answer the math problem I posed to you.

I'm sorry, Tom, I didn't even read the math problem
you posed to me as I don't have time for it right
now. I'm sure anyone could use the distributed
network model to solve your problem, even you.

Never mind.
73,
Tom Donaly, KA6RUH

Loading Coils; was : Vincent antenna
 

Ian White GM3SEK wrote:
Cecil Moore wrote:
Ian White GM3SEK wrote:
Your model can be as elaborate as you like, but it always has to
prove itself against the simple cases that we already know about.

Since I am using the distributed network model proven
valid since before I was born, I don't have to defend
it. Please don't confuse my refusal to spend 36 hours
a day defending the distributed network model with the
validity of the distributed network model.

Likewise there are no glitches in the standard circuit models for
inductance and capacitance.

Really???? Just try your lumped inductance model on
a helical antenna and get back to us.

Yet more stinking dishonest quoting from Cecil. What I ACTUALLY wrote was:

"Likewise there are no glitches in the standard circuit models for
inductance and capacitance. They work just fine, for all cases where the
dimensions of the circuit are very small with respect to the wavelength,
so that distributed effects and radiation are negligible. Where those
assumptions are no longer accurate, we can extend the simple model to
include some corrections. But the most important point is, we always
know that we're building up from a solid foundation."

There's no debating with that man. I've made my technical points, and
I'm out.



That's why you shouldn't take him seriously. He's like a college
wrestler who bites.
73,
Tom Donaly, KA6RUH

Loading Coils; was : Vincent antenna
 

Tom Donaly wrote:
Ian White GM3SEK wrote:
. . .
There's no debating with that man. I've made my technical points, and
I'm out.



That's why you shouldn't take him seriously. He's like a college
wrestler who bites.
73,
Tom Donaly, KA6RUH

We gotta learn better than to get down in the mud to rassle with a pig.
You both get dirty, and the pig loves every minute of it.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
Gene Fuller wrote:
I believe you said you saw about a 7% shift between the two inputs to
your scope.

I don't recall saying anything like that. I don't even
know what that means. 7% of what?

Cecil,

Sorry, English is not my native language this month. I must have
misinterpreted the following message sent by you (11/30/2007, 3:35 pm).

****************

Jim Kelley wrote:
Cecil Moore wrote:

I measured a ~25 nS delay in a 75m bugcatcher coil.

What did you use to make that measurement? (I hope you don't say you
used a Bird Wattmeter.)

I've described it before. I used a dual-trace
100 MHz O-scope and estimated the phase angle
between the two traces at about 7% of a cycle.
That phase angle was certainly NOT ANYWHERE
NEAR the 4.5 degrees reported by W8JI.

W8JI measured a 4.5 degree phase shift in the
standing-wave current being used for the
measurement although virtually no phase
information exists in the standing-wave current
phase. W7EL made exactly the same mistake in
his measurements. No wonder the two agree.
--
73, Cecil http://www.w5dxp.com


****************

73,
Gene
W4SZ

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:

I've described it before. I used a dual-trace
100 MHz O-scope and estimated the phase angle
between the two traces at about 7% of a cycle.
That phase angle was certainly NOT ANYWHERE
NEAR the 4.5 degrees reported by W8JI.

W8JI measured a 4.5 degree phase shift in the
standing-wave current being used for the
measurement although virtually no phase
information exists in the standing-wave current
phase. W7EL made exactly the same mistake in
his measurements. No wonder the two agree.

*Chuckle* I made the "mistake" of measuring current, the definition of
which can be found in any elementary electrical circuits text. Contrary
to Cecil's objections, phase is a property of periodic steady state
current (as can also be discovered from reading a basic text), and
certainly can be measured. I measured it and so did Tom, but Cecil sure
doesn't seem to like the results. Cecil's and his scope are apparently
able to measure something else -- whatever it is, I'm afraid my scope
doesn't have the magical properties needed to measure it.

I did, however, do at least a couple of things which Cecil might have
overlooked. One is that I was careful to terminate each of the current
probes with a low-resistance low-reactance load to reduce the insertion
impedance to a very low value. Another is that I put both probes on the
same wire to verify that their outputs were in phase. These steps alone
might have broken the magic spell necessary to measure whatever
different kinds of current Cecil imagines.

Can anyone point me to any reference to "standing-wave current" in any
reputable text? As far as I can tell, it's something Cecil made up to
mean whatever is necessary at the moment to discount others'
measurements. It seems to be working quite well -- in the endless
discussions, he's trotted it out many times without anyone to my
recollection even asking him what it is and how it differs from the
current described in textbooks (you know, the rate of charge flow?). Or
why "virtually no phase information" exists in it. A periodic waveform
with no phase information? Huh?

There's no mystery about traveling or standing waves -- both are very
well understood, mathematically rigorous, and have been used for over a
century with great success in the design of countless real things that
work. But muddled "standing wave currents" and bouncing waves of average
power, supported only by hand waving and misdirection, don't bear much
resemblance to the highly developed, rigorous, and self-consistent body
of knowledge that's served us so well for so long.

But each to his own.

Roy Lewallen, W7EL