Cecil,

It seems that you on purpose remove/ignore things that you don't like,
but (you know) are true.

A CLC pi filter doesn't know the difference between:

1. 100 Ohms lumped circuit load
2. RC = +0.33333 (for 50 Ohms reference)
3. VSWR = 3 (voltage minimum, for a 300 Ohms reference)

It seems you don't want to notice that.

That it is convenient to use transmission line theory to calculate the
load as seen by a PA when transmission line sections are involved, is
OK, I didn't deny that.

That lumped circuit theory has limitations is fully understood.
Frequently transmission line effects are modelled using parasitic L
and C additions yielding accurate models valid up to GHz frequencies
(depending on the size of the component). We are below 30 MHz (for
this topic).

Here the experience of the Engineer comes into play: when you can use
a lumped circuit model and when you need to use transmission line
models (the particle/wave issue is similar)?

A helical inductor of an antenna no longer small w.r.t. wavelength may
be better modelled with transmission line theory, but that is OT.
Even the L of the CLC filter, you can model with a lumped circuit
equivalent with more than sufficient accuracy. This is daily business
for manufacturers of inductive components.

Generally, converting results from transmission line models to
impedance in combination with lumped circuit theory to calculate the
load as seen by the active device, is daily practice. Especially here,
as we are dealing with narrow band signals and don't have to model the
behavior for harmonics. But for some reason you don't want to see
that, and you elevate transmission line theory to a goal.

So again, once you did the conversion to Z, you no longer have to
worry about transmission line issues in the load or cabling (including
reflection coefficient) when treating your PA's CLC pi filter.

Now speed of light becomes important in a CLC pi filter for a HF PA,
when becomes "Gaussian" of importance (and may lose all the readers of
this topic)?

With kind regards,



Wim
PA3DJS
www.tetech.nl

On May 16, 2:58*pm, Wimpie wrote:
A CLC pi filter doesn't know the difference between:

1. 100 Ohms lumped circuit load
2. RC = +0.33333 (for 50 Ohms reference)
3. VSWR = 3 (voltage minimum, for a 300 Ohms reference)

It seems you don't want to notice that.

It is not worth wasting my time to notice since *everyone* already
knows that a CLC pi filter is not alive and doesn't have a brain so it
must necessarily be dumb as a dead stump. You, OTOH, hopefully being
smarter than the average CLC pi filter, should know that the
conditions existing within a resistor are different from the
conditions existing within an antenna with the same feedpoint
impedance. Hint: If you don't know what is in the box, alleviate your
ignorance by looking inside the box. If you put on the blinders and
refuse to look, then you will make errors like you did earlier while
measuring an s11 of zero when it was actually 0.3333.

Even the L of the CLC filter, you can model with a lumped circuit
equivalent with more than sufficient accuracy.

When the task is to determine the exact delay through the inductor,
how the heck can the lumped circuit model tell you that?
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

On May 16, 3:29*pm, Cecil Moore wrote:
When the task is to determine the exact delay through the inductor,
how the heck can the lumped circuit model tell you that?

Wim, I forgot to note that using your stated methods, W8JI "measured"
a 3ns delay through a 10" long, 2" diameter, 100 turn, 100uh, 80m
mobile loading coil. Doesn't a 4 MHz RF wave traveling the length of a
large 100uH air-core 80m loading coil in 3 ns give you some pause for
reconsidering your methods? Every wonder why computer manufacturers
don't install 100uh coils in series with their computer bus lines to
speed up their computers? :-)
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

On 16 mayo, 22:55, Cecil Moore wrote:
On May 16, 3:29*pm, Cecil Moore wrote:

When the task is to determine the exact delay through the inductor,
how the heck can the lumped circuit model tell you that?

Wim, I forgot to note that using your stated methods, W8JI "measured"
a 3ns delay through a 10" long, 2" diameter, 100 turn, 100uh, 80m
mobile loading coil. Doesn't a 4 MHz RF wave traveling the length of a
large 100uH air-core 80m loading coil in 3 ns give you some pause for
reconsidering your methods? Every wonder why computer manufacturers
don't install 100uh coils in series with their computer bus lines to
speed up their computers? :-)
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

I am sorry Cecil, but for the current topic, the answer is no. Please
stay to the topic, or start a new one.

Wim
PA3DJS
www.tetech.nl

On 16 mayo, 22:29, Cecil Moore wrote:
On May 16, 2:58*pm, Wimpie wrote:

A CLC pi filter doesn't know the difference between:

1. 100 Ohms lumped circuit load
2. RC = +0.33333 (for 50 Ohms reference)
3. VSWR = 3 (voltage minimum, for a 300 Ohms reference)

It seems you don't want to notice that.

It is not worth wasting my time to notice since *everyone* already
knows that a CLC pi filter is not alive and doesn't have a brain so it
must necessarily be dumb as a dead stump. You, OTOH, hopefully being
smarter than the average CLC pi filter, should know that the
conditions existing within a resistor are different from the
conditions existing within an antenna with the same feedpoint
impedance. Hint: If you don't know what is in the box, alleviate your
ignorance by looking inside the box. If you put on the blinders and
refuse to look, then you will make errors like you did earlier while
measuring an s11 of zero when it was actually 0.3333.

Even the L of the CLC filter, you can model with a lumped circuit
equivalent with more than sufficient accuracy.

When the task is to determine the exact delay through the inductor,
how the heck can the lumped circuit model tell you that?

Just via the capacitance to ground (for example a CLC model of an
inductor well below the first self resonance frequency). But when
looking to a PA, there is often an additional capacitance left and
right of the inductor that causes the most of the phase shift. I did
some tesla coiling, so I am aware of the various models for single
layer inductors. You are further drifting away from the main subject
(PA output impedance and what mismatch will do).

--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK


Wim
PA3DJS
www.tetech.nl

On May 16, 4:55*pm, Wimpie wrote:
You are further drifting away from the main subject

Actually, you are further drifting away from basic fundamental EM
physics and I am not in the mood to follow you. Since you do not
understand the basic fundamentals of EM wave interference, you cannot
possibly understand what is going on inside an active source with
invading reflected energy. You might as well be arguing that God
causes everything because your lack of the understanding of the basic
physics of interference causes your concepts to resemble religion more
than anything scientific. That's not an ad hominen attack, just an
observation based on the technical ignorance of EM wave interference
that you have presented here on this newsgroup. Sorry for being so
blunt but anyone who chooses to be ignorant, when there is knowledge
available, doesn't deserve much respect, IMO.

Since you have failed to answer the simplest of questions about
passive circuits, exactly what makes you an expert on active circuits?
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

On 17 mayo, 00:37, Cecil Moore wrote:
On May 16, 4:55*pm, Wimpie wrote:

You are further drifting away from the main subject

Actually, you are further drifting away from basic fundamental EM
physics and I am not in the mood to follow you. Since you do not
understand the basic fundamentals of EM wave interference, you cannot
possibly understand what is going on inside an active source with
invading reflected energy. You might as well be arguing that God
causes everything because your lack of the understanding of the basic
physics of interference causes your concepts to resemble religion more
than anything scientific. That's not an ad hominen attack, just an
observation based on the technical ignorance of EM wave interference
that you have presented here on this newsgroup. Sorry for being so
blunt but anyone who chooses to be ignorant, when there is knowledge
available, doesn't deserve much respect, IMO.

Since you have failed to answer the simplest of questions about
passive circuits, exactly what makes you an expert on active circuits?
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

Cecil,

For Walt I made an exception, but I normally don't do someone's
homework. I also don't spend my time solving non-relevant problems; I
have more interesting quests waiting. If you show up with a relevant
quest, maybe I am willing to dive into it.

I am not calling myself an expert, I just designed some PA's, ranging
from kHz to GHz and from mW to kW, some of them with efficiencies to
over 95%. Together with antenna design and consultancy it assures me
that at the end of each month I have some money left.

With kind regards,


Wim
PA3DJS

On May 17, 4:49*am, Wimpie wrote:
If you show up with a relevant
quest, maybe I am willing to dive into it.

Wim, here is why my questions for you are more than just relevant. It
is imperative that someone lecturing us on happenings inside that PA
RF volcano be able to understand what is occurring during a passive
event involving forward and reflected EM fields and waves occurring at
an impedance discontinuity outside of a PA.

Two of the physical quantities that must be conserved are energy and
momentum. EM RF fields and waves contain both energy and momentum
which must be conserved. I have asked you to tell us exactly what laws
of physics govern the reversal of the momentum and direction of energy
flow at a Z0-match at a passive impedance discontinuity in a
transmission line. You have refused to do so and asserted that such is
irrelevant. I contend that I could not have asked a more relevant
question - thus the reluctance to provide an answer.

The answer to the question is contained in my energy analysis article
at:
http://www.w5dxp.com/energy.htm
A passive Z0-match relies on superposition of waves accompanied by
interference effects to explain the reversal of reflected wave energy
direction and momentum. Walter Maxwell has called the process a
"virtual open-circuit" or a "virtual short". In my article, I explain
how it is a two-step process involving normal reflections and
interference patterns at the impedance discontinuity. It works exactly
like non-reflective glass covering a picture with its 1/4WL thin-film
coating where two sets of reflected light waves undergo destructive
interference toward the viewer and, honoring the conservation of
energy and momentum, reverse their direction and momentum and flow in
the opposite direction toward the picture. This is a well-understood
phenomenon from sophomore physics 201. Why most RF engineers don't
understand this simple physical process involving EM wave interference
is beyond belief. Here's the Florida State University web page again:

micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/
waveinteractions/index.html

Set the java application for opposite phase and when the result is
zero, scroll down to the bottom of the page to find out what happens
to the energy components in the two waves that cancel to zero. Those
energy components "are redistributed to regions that permit
constructive interference" just as they are at a Z0-match in an RF
transmission line where there are only two possible directions for RF
energy flow. For every destructive interference event in one
direction, there will be an equal magnitude constructive interference
event in the opposite direction. At Walt's "virtual short", total
destructive interference energy toward the source is redistributed as
constructive interference energy back toward the load.

I studied this subject in my EE courses at Texas A&M during the
1950's. The textbook was: "Fields and Waves in Modern Radio", by Ramo
and Whinnery, (c) 1944, 1953. The subject is covered under "Quarter-
Wave Coating for Eliminating Reflections" in the chapter titled:
"Propagation and Reflection of Electromagnetic Waves".
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

On 17 mayo, 14:29, Cecil Moore wrote:
On May 17, 4:49*am, Wimpie wrote:

If you show up with a relevant
quest, maybe I am willing to dive into it.

Wim, here is why my questions for you are more than just relevant. It
is imperative that someone lecturing us on happenings inside that PA
RF volcano be able to understand what is occurring during a passive
event involving forward and reflected EM fields and waves occurring at
an impedance discontinuity outside of a PA.

Two of the physical quantities that must be conserved are energy and
momentum. EM RF fields and waves contain both energy and momentum
which must be conserved. I have asked you to tell us exactly what laws
of physics govern the reversal of the momentum and direction of energy
flow at a Z0-match at a passive impedance discontinuity in a
transmission line. You have refused to do so and asserted that such is
irrelevant. I contend that I could not have asked a more relevant
question - thus the reluctance to provide an answer.

The answer to the question is contained in my energy analysis article
at:http://www.w5dxp.com/energy.htm
A passive Z0-match relies on superposition of waves accompanied by
interference effects to explain the reversal of reflected wave energy
direction and momentum. Walter Maxwell has called the process a
"virtual open-circuit" or a "virtual short". In my article, I explain
how it is a two-step process involving normal reflections and
interference patterns at the impedance discontinuity. It works exactly
like non-reflective glass covering a picture with its 1/4WL thin-film
coating where two sets of reflected light waves undergo destructive
interference toward the viewer and, honoring the conservation of
energy and momentum, reverse their direction and momentum and flow in
the opposite direction toward the picture. This is a well-understood
phenomenon from sophomore physics 201. Why most RF engineers don't
understand this simple physical process involving EM wave interference
is beyond belief. Here's the Florida State University web page again:

micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/
waveinteractions/index.html

Set the java application for opposite phase and when the result is
zero, scroll down to the bottom of the page to find out what happens
to the energy components in the two waves that cancel to zero. Those
energy components "are redistributed to regions that permit
constructive interference" just as they are at a Z0-match in an RF
transmission line where there are only two possible directions for RF
energy flow. For every destructive interference event in one
direction, there will be an equal magnitude constructive interference
event in the opposite direction. At Walt's "virtual short", total
destructive interference energy toward the source is redistributed as
constructive interference energy back toward the load.

I studied this subject in my EE courses at Texas A&M during the
1950's. The textbook was: "Fields and Waves in Modern Radio", by Ramo
and Whinnery, (c) 1944, 1953. The subject is covered under "Quarter-
Wave Coating for Eliminating Reflections" in the chapter titled:
"Propagation and Reflection of Electromagnetic Waves".
--
73, Cecil, w5dxp.com
"Halitosis is better than no breath at all.", Don, KE6AJH/SK

Hello Cecil,

I am familiar with quarter wave (and multi layer) coatings to reduce
reflection. I am not waiting for a lecture on (un)bounded wave
propagation. If I don't have something present in my mind, I know
where to find it.

As mentioned earlier, you can convert all the wave phenomena in the
coaxial feed line to impedance as seen by the PA. You are unnecessary
complicating things, hence loosing more public that may have interest
in this topic.

Maybe you (and other people) should carry out the experiments I
suggested in this thread (looking to forward power, net power and DC
input power versus small load mismatch [normally referenced to 50
Ohms] ).

With kind regards,


Wim
PA3DJS
www.tetech.nl