"Kjell W. Strom" skrev i en meddelelse
...
Walt: For somebody who missed out on Reflections II, it looks like a lot
of fine reading - many thanks!

Sven: Got delivery here in Holland today.

73,
Kjell PB3SM - SM6CPI


"Sven Lundbech" wrote in message
k...
"walt" skrev i en meddelelse
...
To order a copy of the 3rd edition of Reflections, authored by Walter
Maxwell, W2DU, go to the W2DU website at www.w2du.com, then go to page
2 and click on the following:

Order Reflections III from CQ Online BookStore

Walt, W2DU

Dear Walt,

Ever since reading your 1973 QST articles, being a second-year student at
the Polytechnics/Technical University of Copenhagen, I have referred to
your ground-breaking work for removing the myths and misunderstandings of
the (un)importance of the swr over and over again. Somewhere I still have
the ageing photocopies of all the articles. But having the opportunity to
get it all and more in one piece in Reflections III is really greast. I
have ordered my copy right away.

Later on, both in my professional life after receiving my MSc(EE) as a
radio engineer and during my 19 years as Technical Editor of 'OZ' (the
Danisk QST) I have had to weed out misconceptions about swr and
transmission lines. My early understanding from your work was a great
help. Thanks!

All the best,

vy 73
OZ7S Sven


Got delivery to-day.

As mentioned earlier, most of the stuff is old hat to me - but I really look
forward to dig into the chapters concerning tx output impedance. A highly
controversial subject for decades.

vy 73
OZ7S Sven

"Sven Lundbech" wrote in
k:

....
As mentioned earlier, most of the stuff is old hat to me - but I
really look forward to dig into the chapters concerning tx output
impedance. A highly controversial subject for decades.

Here is a simple little test for the hypothesis that Zs=50+j0 that uses
equipment found in many if not most HF ham shacks.

Owen

Owen Duffy wrote in news:Xns9D81BC11E3183nonenowhere@
61.9.191.5:

"Sven Lundbech" wrote in
k:

...
As mentioned earlier, most of the stuff is old hat to me - but I
really look forward to dig into the chapters concerning tx output
impedance. A highly controversial subject for decades.

Here is a simple little test for the hypothesis that Zs=50+j0 that uses
equipment found in many if not most HF ham shacks.

Oh, the URL: http://vk1od.net/blog/?p=1028 .


Owen

On Apr 25, 3:40*am, W0BTU wrote:
On Apr 16, 8:10*pm, walt wrote:

To order a copy of the 3rd edition of Reflections, authored by Walter
Maxwell, W2DU, go to the W2DU website atwww.w2du.com, then go to page
2 and click on the following:

* * * * * * * * * * * *Order Reflections III from CQ Online BookStore

Walt, W2DU

I've seen people talking about it in the other forums, and I looked at
the three sample excerpts at w2du.com. That's all I know about it. It
sounds interesting, but I need to at least see a table of contents
(index would be nice, too) before I think about ordering it. Is that
possible?

TIA.

73 Mike

Hi Mike,

Since attachments aren't allowed on these NGs I can't send what you
want. If you'll send me your email address I'll send you some material
from the book. My email address is .

Walt, W2DU

Dear Walt,

Ever since reading your 1973 QST articles, being a second-year student at
the Polytechnics/Technical University of Copenhagen, I have referred to
your ground-breaking work for removing the myths and misunderstandings of
the (un)importance of the swr over and over again. Somewhere I still have
the ageing photocopies of all the articles. But having the opportunity to
get it all and more in one piece in Reflections III is really greast. I
have ordered my copy right away.

Later on, both in my professional life after receiving my MSc(EE) as a
radio engineer and during my 19 years as Technical Editor of 'OZ' (the
Danisk QST) I have had to weed out misconceptions about swr and
transmission lines. My early understanding from your work was a great
help. Thanks!

All the best,

vy 73
OZ7S Sven

Got delivery to-day.

As mentioned earlier, most of the stuff is old hat to me - but I really look
forward to dig into the chapters concerning tx output impedance. A highly
controversial subject for decades.

vy 73
OZ7S Sven

Hello Sven,

Glad you received your copy today. To pique your interest in tx output
impedance, Chapter 19 will do that for you, especially Sec 19.14 on
Page 19.22. This section describes in detail, in fourteen steps, how
the output Z is measured.

I've seen a lot of discussion on this subject, and most of it shows
that many who discuss it don't have a clue to the correct answer.
Which is why I have made many measurements of the output Z to
determine the truth.

The output Z is determined principally by the proper adjustment of the
tank circuit with respect to the load. I'm talking now only about tube
amps with pi-network tank circuit coupling the amp tube to the load. I
cannot comment on solid-state rigs, or those that have no tuning
adjustments.

There are those who believe that the output Z = 50 + j0, and there are
those who believe the Z is much higher. Here's what really happens.
With any practical grid drive, load and tune the amp into a 50 + j0
dummy load to deliver all the available power. In this case the output
Z of the amp will be 50 + j0 ohms.

Now add 50 ohms of inductive reactance to the same dummy load. The
result is now a load impedance of 50 + j50 ohms. Now reload and retune
the pi-network to again deliver all the available power into the new
complex-impedance load. The new output Z? 50 - j50 ohms, the conjugate
of the complex load impedance. In other words, to determine the output
Z of the amp, simply load it into an impedance of known value such
that all the available power is delivered at a reasonable drive level.
The output Z is then the conjugate of the load impedance.

You say you want proof of this simplistic procedure? Fine. It's all
right there in the fourteen steps in Sec 19.14 that describe the
entire measurement procedure. I'm sure you'll find the procedure
enlightening.

Walt, W2DU

On May 23, 10:01*pm, walt wrote:
On Apr 25, 3:40*am, W0BTU wrote:



On Apr 16, 8:10*pm, walt wrote:

To order a copy of the 3rd edition of Reflections, authored by Walter
Maxwell, W2DU, go to the W2DU website atwww.w2du.com, then go to page
2 and click on the following:

* * * * * * * * * * * *Order Reflections III from CQ Online BookStore

Walt, W2DU

I've seen people talking about it in the other forums, and I looked at
the three sample excerpts at w2du.com. That's all I know about it. It
sounds interesting, but I need to at least see a table of contents
(index would be nice, too) before I think about ordering it. Is that
possible?

TIA.

73 Mike

Hi Mike,

Since attachments aren't allowed on these NGs I can't send what you
want. If you'll send me your email address I'll send you some material
from the book. My email address is .

Walt, W2DU

Mike, apparently one can't divulge one's email address on this NG.
However, we'll fool 'em--the word preceding @ is walt. So there, too.

Walt

On May 23, 4:31*am, Owen Duffy wrote:
Owen Duffy wrote in news:Xns9D81BC11E3183nonenowhere@
61.9.191.5:

"Sven Lundbech" wrote in
. dk:

...
As mentioned earlier, most of the stuff is old hat to me - but I
really look forward to dig into the chapters concerning tx output
impedance. A highly controversial subject for decades.

Here is a simple little test for the hypothesis that Zs=50+j0 that uses
equipment found in many if not most HF ham shacks.

Oh, the URL:http://vk1od.net/blog/?p=1028.
Owen

While the analysis of transmitter output impedance in Reflections is
flawed,
experiments (claimed to be repeatable) described in Reflections appear
to
support the conclusions of the flawed analysis.

It would be highly valuable if the results of these experiments could
be
explained in a manner that aligns with established understandings.

Such an explanation might start by describing the circuit conditions
that
result from following the manufacturer’s tuning procedures. After
all,
these usually depend on measuring currents and voltages so are only
indirectly related to power. Perhaps the resulting conditions are not
as they are usually assumed to be.

Try as I might, I have not been able to derive a mechanism to explain
the observations in Reflections. But the explanations offered in
Reflections require large chunks of linear circuit theory to be
discarded,
so this does not seem to be an appropriate path.

....Keith

On May 24, 6:30*am, Keith Dysart wrote:
Such an explanation might start by describing the circuit conditions
that result from following the manufacturer’s tuning procedures.

On an old tube transmitter, e.g. a Globe Scout, when the manufacturer
specifed a particular grid current and a particular plate current,
does that imply a particular single resistive load line for the final
tube? Why were those particular grid and load currents chosen? Maximum
efficiency? Tube life? Minimum distortion?
--
TNX & 73, Cecil, w5dxp.com

On May 24, 9:23*am, Cecil Moore wrote:
On May 24, 6:30*am, Keith Dysart wrote:

Such an explanation might start by describing the circuit conditions
that result from following the manufacturer’s tuning procedures.

On an old tube transmitter, e.g. a Globe Scout, when the manufacturer
specifed a particular grid current and a particular plate current,
does that imply a particular single resistive load line for the final
tube? Why were those particular grid and load currents chosen? Maximum
efficiency? Tube life? Minimum distortion?

Excellent questions. I have often wondered if the manufacturer's
tuning
procedures had anything to do with maximizing output power transfer,
or
were they, in fact, optimizing some other aspect.

....Keith

On May 24, 7:30*am, Keith Dysart wrote:
On May 23, 4:31*am, Owen Duffy wrote:



Owen Duffy wrote in news:Xns9D81BC11E3183nonenowhere@
61.9.191.5:

"Sven Lundbech" wrote in
. dk:

...
As mentioned earlier, most of the stuff is old hat to me - but I
really look forward to dig into the chapters concerning tx output
impedance. A highly controversial subject for decades.

Here is a simple little test for the hypothesis that Zs=50+j0 that uses
equipment found in many if not most HF ham shacks.

Oh, the URL:http://vk1od.net/blog/?p=1028.
Owen

While the analysis of transmitter output impedance in Reflections is
flawed,
experiments (claimed to be repeatable) described in Reflections appear
to
support the conclusions of the flawed analysis.

It would be highly valuable if the results of these experiments could
be
explained in a manner that aligns with established understandings.

Such an explanation might start by describing the circuit conditions
that
result from following the manufacturer’s tuning procedures. After
all,
these usually depend on measuring currents and voltages so are only
indirectly related to power. Perhaps the resulting conditions are not
as they are usually assumed to be.

Try as I might, I have not been able to derive a mechanism to explain
the observations in Reflections. But the explanations offered in
Reflections require large chunks of linear circuit theory to be
discarded,
so this does not seem to be an appropriate path.

...Keith

Keith, would you please elaborate on why you believe my analysis of
transmitter output impedance is flawed? And what is the basis for your
belief that my explanations in Reflections require large chunks of
linear circuit theory to be discarded. Could it be because you
consider the source resistance in the transmitter to be dissipative,
as in the classical generator? If so, you must be made to realize that
the source resistance of the transmitter is non-dissipative, which is
the reason that its efficiency can exceed 50%.

Or are you considering the output characteristic of the transmitter to
be non-linear? This is not the case, because the effect of energy
storage in the tank circuit isolates the non-linear input from the
output circuit, which is linear as evidenced by the almost perfect
sine wave appearing at the output of the tank.

One last question: Are you basing your dissatisfaction of Reflections
from reviewing the 2nd or 3rd edition? Chapter 19 has been expanded in
the 3rd edition, in which I presented additional proof of my position
on the subject that you should be aware of. If you haven't yet seen
the addition that appears in the 3rd ed, please let me know so that I
can send you a copy of the addition. Also include your email address
so I can send it.

Keith, you are the only person I know of who appears to have found
flaws in my presentation on this subject. Which is why I'm anxious to
know exactly why you believe my presentation is flawed.

Walt Maxwell, W2DU