Loading Coils; was : Vincent antenna
 

On 8 Dec, 07:56, Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
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?

As far as impedance discontinuity *points* go, a nonsense
question.

How many nanoseconds does it take for a signal to travel
through a dimensionless point???? Well, let's see. What
is the speed of light multiplied by zero? Hmmmm, that's
a really tough one.

At any instant of time the forward voltage on
one side of the discontinuity *point* has a relative phase
difference from the forward voltage on the other side of
the *point*. This relative phase difference is constant as
long as the conditions remain unchanged.

The reason that it takes nanoseconds for a signal to travel
through a 75m Bugcatcher loading coil is that the coil is
NOT a dimensionless point. Mine occupies almost 200 cubic
inches. Loading coils with zero dimensions exist *only* in
the human mind and are impossible in reality.
--
73, Cecil http://www.w5dxp.com

Is "reality" confined to the speed of our brains or the
reflexes of our muscles or vision capabilities of our eyes?
To create is to produce to take the place of "nothing"
Your quest of TOTAL victory has reduced you to tunnel vision
Art

Loading Coils; was : Vincent antenna
 

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 ...

JS

Loading Coils; was : Vincent antenna
 

John Smith wrote:
Cecil Moore wrote:
http://www.w5dxp.com/coiltest.gif

Beautiful artwork! What'd you use to construct that?

EZNEC and Paint.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

art wrote:
Your quest of TOTAL victory has reduced you to tunnel vision

Please don't confuse my not choosing to spend 36
hours a day defending the models I use with the
validity of the model. The lumped circuit model
is known to fail in distributed network configurations.
The distributed network model is known to work for
both lumped circuits and distributed network problems.
I am simply using the distributed network model.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

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.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
Ian White GM3SEK wrote:
That is also the sensible way to think about loaded antennas.
Calculate it the simple way first, assuming lumped inductive loading,
and then apply corrections as necessary. As I've said before, this
simple, solid method is the one that works. It can take you straight
to a workable prototype, which can be quickly adjusted to frequency.
Countless authors have demonstrated how to do this, and anyone can
download G4FGQ's MIDLOAD program to do the same.

The point is that IT OBVIOUSLY DOESN'T WORK, Ian, for
the delay through a loading coil. If it worked, W8JI
would not have gotten a 3 ns delay through a 2" dia,
100 TPI, 10" long loading coil. If his test setup
looked like mine, he would have measured a valid
delay around 25 ns.

http://www.w5dxp.com/coiltest.gif

Ian, are you afraid to run that test for yourself?

Cecil insists that simple routine reality tests are a "diversion".

Please don't twist my words. I insist that simple routine
*UNreality* tests are a diversion. But, my personal opinion
doesn't change anything. The model that I am using works. The
model that W8JI is using doesn't work.

Please take a look at: http://www.w5dxp.com/coil512.ez
and tell me why EZNEC disagrees with W8JI's model.

Cecil,

I believe you said you saw about a 7% shift between the two inputs to
your scope. If the 75 meter frequency was 4 MHz that shift would
correspond to a time delay of 17.5 ns. Not 3 ns, but not 25 ns either.
Is that just an estimate based on rounding to the nearest 25 ns?

This entire issue has become one of counting angels on pinheads, at
least from a numerical view. One angel more or less really doesn't matter.

73,
Gene
W4SZ

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
art wrote:
Your quest of TOTAL victory has reduced you to tunnel vision

Please don't confuse my not choosing to spend 36
hours a day defending the models I use with the
validity of the model. The lumped circuit model
is known to fail in distributed network configurations.
The distributed network model is known to work for
both lumped circuits and distributed network problems.
I am simply using the distributed network model.

Yes, but not using it very well, or you would have been
able to answer the math problem I posed to you.
73,
Tom Donaly, KA6RUH

Loading Coils; was : Vincent antenna
 

On Dec 8, 9:22 am, Cecil Moore wrote:
Keith Dysart wrote:
You should count your posts on (re)reflections at the
output terminals of amplifiers.

Conceptually, I know what has to happen based on the
principle of conservation of energy, i.e. all energy
is conserved. If the reflected wave energy is not
entering the source, it is being reflected at the
source. That is all I was saying during those posts.

Actually, you said much more than that, some of
which was quite wrong. And you are right, some
of the errors would be entirely consistent with not
understanding amplifiers. Especially the
superposition ones.
But then why not take the opportunity to learn?
Instead of arguing from a point which you now
claim was ignorance.

....Keith

Loading Coils; was : Vincent antenna
 

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.


--

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

Loading Coils; was : Vincent antenna
 

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?
--
73, Cecil http://www.w5dxp.com