On 11 jun, 16:27, Cecil Moore wrote:
On Jun 11, 12:56*pm, Richard Fry wrote:

Followup: *Those denying the existence of reflected signals within an
antenna system may wish to view the measurement of such signals, at
the link below.

Or at this link. Scroll down to "Using Dielectric Beamsplitters to
find the "missing energy" in destructive interference".

http://www.teachspin.com/instruments...eriments.shtml

I guarantee that every optical physicist who is reading this thread is
laughing at the ignorance of the alleged RF gurus.
--
73, Cecil, w5dxp.com

Hello, here we are...! :)

At the risk of naïve and conciliatory I still thinking that to some
extent this is a problem of "same cat seen from different points of
view".

What if the question is formulated in terms apart, for example =
generator responses to load differences, and by what mechanism a
transmission line transforms impedances to presents to the generator
those different loads?
In that formulation I think there are room to simple, basic, and
understandable electrical laws to account for generator behaviour and
TL travelling waves interference phenomenom to account for Z
transformings.

From my perspective your main differences are reducible

73

Miguel Ghezzi - LU6ETJ

On Jun 11, 10:03*pm, lu6etj wrote:
On 11 jun, 16:27, Cecil Moore wrote:

On Jun 11, 12:56*pm, Richard Fry wrote:

Followup: *Those denying the existence of reflected signals within an
antenna system may wish to view the measurement of such signals, at
the link below.

Or at this link. Scroll down to "Using Dielectric Beamsplitters to
find the "missing energy" in destructive interference".

http://www.teachspin.com/instruments...eriments.shtml

I guarantee that every optical physicist who is reading this thread is
laughing at the ignorance of the alleged RF gurus.
--
73, Cecil, w5dxp.com

Hello, here we are...! *:)

At the risk of naïve and conciliatory I still thinking that to some
extent this is a problem of "same cat seen from different points of
view".

What if the question is formulated in terms apart, for example =
generator responses to load differences, and by what mechanism a
transmission line transforms impedances to presents to the generator
those different loads?
In that formulation I think there are room to simple, basic, and
understandable electrical laws to account for generator behaviour and
TL travelling waves interference phenomenom to account for Z
transformings.

From my perspective your main differences are reducible

73

Miguel Ghezzi - LU6ETJ

of course, but that is no fun!

On Fri, 11 Jun 2010 14:29:17 -0700 (PDT), K1TTT
wrote:

you can qualify an impedance as non-dissipative

It's called reactance.

There are certainly some contortions that have evolved from an
argument that the source lacks the ability to dissipate.

Impedance = (R ± jX) Ohm

This is well known by all and yet it seems unsatisfactory and
impossible to measure in a Tube even when R is exhibited both by
measurement and by heat - something that by all normal accounts is
evidence of dissipation. That same heat seems to be unaccountable
because it's non-linear? If you use this heat on an ice cube, do you
get harmonics? Even or odd?

If it doesn't dissipate it must be because it has NOhms. If we embark
further on this mysterious Load Conjugation with a loss-less resistor,
what would we see for the Load Objurgation formula?

rraaZ = (Rr ± iR ± jX) NOhm

We must now have a Nimpedance measured along a second (hither too
unreported) imaginary axis. I can imagine the dawn of the new Photon
Ninterferences that will emerge from this.

KEWEL !

73's
Richard Clark, KB7QHC

On Fri, 11 Jun 2010 20:31:42 GMT, Owen Duffy wrote:

there is a proposition that a transmitter "designed/adjusted
for, and expecting a 50 + j 0 ohm load" can be well represented by a
Thevenin equivalent circuit and naturally has Zeq=50+j0. However, that
proposition is easily proven wrong by valid experiments in the real
world

Using the same transmitter originally "designed/adjusted
for, and expecting a 50 + j 0 ohm load"?

I don't suppose this anecdote has any data behind it, does it?

The easy proof has yet to wrong Walt's proposition - or did he state
something to the contrary my reading that he represented a Thevenin
equivalent circuit in the first two steps of his recent report?

73's
Richard Clark, KB7QHC

Richard Clark wrote in
news
On Fri, 11 Jun 2010 20:31:42 GMT, Owen Duffy wrote:
....
I don't suppose this anecdote has any data behind it, does it?

I have performed many tests on many radios. One documented example is at
http://vk1od.net/blog/?p=1045 .

The concept is dealt with in more depth at http://vk1od.net/blog/?p=1028
..

Thing is that those supporting the Zeq=50 proposition, declare that since
the test showed that Zeq (or Zs in the article) is not approximately 50
+j0, then the radio isn't "designed/adjusted for, and expecting a 50 + j
0 ohm load".

Thing is that you cannot use the measured VSWR to reasonably predict the
reduction in power output (Mismatch Loss) on many HF ham radio
transceivers.

I invite you and others to perform the same test. You will realise that
one, or even 100 supporting tests do not prove the proposition, but one
valid test to the contrary is damaging.

Owen

On Jun 11, 11:27*pm, Richard Clark wrote:
On Fri, 11 Jun 2010 14:29:17 -0700 (PDT), K1TTT
wrote:

you can qualify an impedance as non-dissipative

It's called reactance.

not always. there is a non-dissipative resistance. a lossless
transmission line has a pure real impedance, but no dissipation.

On Jun 12, 12:19*am, Owen Duffy wrote:
Richard Clark wrote innews


On Fri, 11 Jun 2010 20:31:42 GMT, Owen Duffy wrote:
...
I don't suppose this anecdote has any data behind it, does it?

I have performed many tests on many radios. One documented example is athttp://vk1od.net/blog/?p=1045.

The concept is dealt with in more depth athttp://vk1od.net/blog/?p=1028
.

Thing is that those supporting the Zeq=50 proposition, declare that since
the test showed that Zeq (or Zs in the article) is not approximately 50
+j0, then the radio isn't "designed/adjusted for, and expecting a 50 + j
0 ohm load".

Thing is that you cannot use the measured VSWR to reasonably predict the
reduction in power output (Mismatch Loss) on many HF ham radio
transceivers.

I invite you and others to perform the same test. You will realise that
one, or even 100 supporting tests do not prove the proposition, but one
valid test to the contrary is damaging.

Owen

define "mismatch loss".

and why would you expect that vswr is a good predictor of power
output? other than radios that use vswr sensing circuits to reduce
power output to protect their output transistors?

and why would anyone expect the output of an rf amplifier to be linear
except in a narrow range of selected loads and tuning conditions?
thats just plain crazy!

K1TTT wrote in
:


define "mismatch loss".

Mismatch loss is the reduction in power available in a mismatched load
compared to a matched load. Mismatch Loss can be calculated in linear
systems with Zs purely real as 1-rho^2. I wrote some notes at
http://vk1od.net/blog/?p=659 which discusses the underlying assumptions.


and why would you expect that vswr is a good predictor of power
output? other than radios that use vswr sensing circuits to reduce
power output to protect their output transistors?

The concept of Mismatch Loss is a sound one, but application to a typical
ham transmitter is flawed because the underlying assumptions are violated
..


and why would anyone expect the output of an rf amplifier to be linear
except in a narrow range of selected loads and tuning conditions?
thats just plain crazy!


Yes.

Owen

On Jun 11, 5:03*pm, lu6etj wrote:
From my perspective your main differences are reducible

The basic argument revolves around what math shortcuts can be used to
solve a particular problem vs what is actually happening in reality
according to the accepted laws of physics. I agree one doesn't
necessarily need to understand the laws of physics to solve a problem
but one should probably know enough physics to recognize when those
laws of physics are being violated by one's argument.
--
73, Cecil, w5dxp.com

On 11 jun, 23:26, Cecil Moore wrote:
On Jun 11, 5:03*pm, lu6etj wrote:

From my perspective your main differences are reducible

The basic argument revolves around what math shortcuts can be used to
solve a particular problem vs what is actually happening in reality
according to the accepted laws of physics. I agree one doesn't
necessarily need to understand the laws of physics to solve a problem
but one should probably know enough physics to recognize when those
laws of physics are being violated by one's argument.
--
73, Cecil, w5dxp.com
............
of course, but that is no fun!
I agree
......
As a courtesy to me, a foreigner tourist ham, would you mind stop for
a brief moment your more general differences and tell me if you agree
on the behavior of a Thevenin generator with a series resistance of 50
ohms in relation to changes in impedance of a lossless TL predicted by
the Telegrapher's equations solutions in terms of the power dissipated
on the load resistance and series resistence of Thevenin source?
I am pretty serious about this: until today I could not know if you
agree in that!! :)