W5DXP wrote:
Jim Kelley wrote:

You were the topic of discussion of this post, Cecil. It certainly
wasn't techincal, but I do think it was accurate.


An ethical person would apologize. How about you?

After you, sir.

ac6xg

Jim Kelley wrote:

W5DXP wrote:
An ethical person would apologize. How about you?

After you, sir.

OK, I apologize for any and all angst that I have
caused you (or anyone else on this newsgroup). My
Dad and my best friend both died this year and I
have been in a foul angry mood for most of the time.

I would like for you and me to lay our personality
conflicts to rest, but based on your past actions and
reactions, I really don't think you are capable of
being a gentleman. I have a lot of friends with which
I differ on technical issues, but you are the only one
of them who has ever threatened me. Please prove me
wrong about my opinion of you. I have removed your
address from my email kill file.
--
73, Cecil, W5DXP

W5DXP wrote:

OK, I apologize for any and all angst that I have
caused you (or anyone else on this newsgroup). My
Dad and my best friend both died this year and I
have been in a foul angry mood for most of the time.

I accept your apollogy. I also lost my dad. He died last month and I
was at his side for his last days.

I would like for you and me to lay our personality
conflicts to rest, but based on your past actions and
reactions, I really don't think you are capable of
being a gentleman. I have a lot of friends with which
I differ on technical issues, but you are the only one
of them who has ever threatened me. Please prove me
wrong about my opinion of you.

Well, that didn't last very long. I have never threatened you. I don't
threaten people. Every one of my personal friends knows me as a truely
gentle man. I find it difficult to see how I could ever change your
opinion about anything.

As you may recall, I was virtually your only supporter on this newsgroup
when I joined this quest. I expressed to you my opion that your
approach, if correct, was simple, elegant, and beautiful! We seemed to
share that enthusiasm in this search for a detailed explanation of the
phenomenon. We shared skepticism about reflections from virtual shorts,
and agreed that reflections occur only at physical discontinuities. I
had discussions with several of the regulars here on the issue, lending
support to your point of view about the interference phenomenon. I very
much enjoyed that for once we had a common interest and point of view.
I've corresponded via email with Steve Best, Walter Maxwell, and others
on the issue all prior to having seen part 2 of your paper. After
reading part 2 though, I expressed to you that I had reservations about
the reversal in the direction of energy described in your paper. I
investigated further, and also asked a few of the professors at UC
Irvine to consider the problem. The bottom line turned out that there
is no physical or mathematical way for such a thing to occur - absent a
reflecting media. You wouldn't hear of it. At that point you saw me as
your adversary, and began treating me as such. Since then you've called
me delusional and impugned my intellegence at almost every opportunity.
And yet throughout this whole thing, I've had only one interest. It
is the very same one we both shared at the outset, to discover the
truth. I've conveyed that truth to you to the best of my ability.
And why do you think it is that, through all the insults I've continued
to try to convey it to you? It's because I would like to get back to
the point once again where you and I share a common viewpoint. That's
it. The angst on my part stems from the fact that someone whom I
respect, continually finds the need to insult me. Most of the time
you'll find I've refrained from commenting on the insults and have
simply deleted them. Over the last couple of days however, I spent some
time trying to illustrate what that looks like from my point of view.
And now we find ourselves here.

Of course I appologize for having caused you angst. It was never my
intention to cause angst! And it shouldn't have done so. It should
only have caused you to reconsider your point of view, and consider
another one. I honestly don't believe you have been able to do that -
for whatever reasons. Perhaps the case is not unlike that of a
scientist who has too much career invested in a particular theory. I
don't know. All I know is this is the only less than amicable
relationship I have in my life, and I truely wish it were amicable.

I have removed your
address from my email kill file.

I appreciate that courtesy. It's not something I ever thought was
necessary.

73, Jim AC6XG

W5DXP wrote:

Jim Kelley wrote:

I have never threatened you.


You deny threatening me with loss of your friendship?

That's pretty sappy, Cecil. For one thing, although you might care
about that, I wouldn't presume to think you'd care about it. For
another it's not my MO so, yes. But I've saved all of our
correspondence, so if you can quote a date and time, I can look it up.

As I've already said, the exchage was a request on my part that you
treat me like a friend - as in trying to establish a friendship with
you. To put it into context, it was right after you began taking an
adversarial stance in our conversations. How you can take that as a
threat, I'll never know.

Interesting that's the only thing you had a comment on.

73, ac6xg

Jim Kelley wrote:
I have never threatened you.

You deny threatening me with loss of your friendship?
--
73, Cecil, W5DXP

Cecil, W5DXP wrote:
"What does Terman say in Sec. 4-11?"

I gave a verbatim response from 4-11 at 11:03am on Jul. 17, 2003.

I`ll add the footnote from page 109:
"Another way of expressing this situation is to say that the stub
position and length are so selected that the input impedance of the line
(l1) shunted by the input impedance of the stub-line (a) will equal the
characteristic impedance Zo." (l1 is the length of line between the stub
and ZL. Fig. 4-17 provides position and length of the stub vs. SWR.

The conclusion is that a match is achieved so there is no reflection on
the transmission line. The match has eliminated the reflection which was
there during the transistion period, but no longer appears there during
the steady state. Your Bird wattmeter will show a forward power but no
reflected power because the load with its stub provides a match to the
transmission line.

Best regards, Richard Harrison, KB5WZI

Ian, G3SEK wrote:
"---the Bird "wattmeter" is not really a power sensor."

The Bird wattmeter indicates the watts, joules per second rate at which
energy flows, well enough to be accepted as a world standard portable
instrument.

Denigrating the Bird is specious because my statement, "Your Bird
wattmeter will show a forward power but no reflected power---." is true!
The statement only requires the right Bird element to indicate the
presence or absence of energy flow in one direction or the other. The
Bird is eminently capable.

I used the bird because those familiar with it are confident in its
ability to separate forward power from reverse power. IEEE defines power
as energy in motion, so it could be in perpetual circulation and never
used, but it is still power when the volts and amps coincide.

Best regards, Richard Harrison, KB5WZI

Ian, G3SEK wrote:
"1. The Bird wattmeter does not in fact sense power."

The speedometer does not measure miles nor hours, but it can
satisfactorily indicate miles per hour. So, what?

"2. It only indicates power due to its calibration."

Without calibration most instruments only serve as crude indicators. The
usual Bird is calibrated for a 50-ohm line which enforces its Zo. Use
the common Bird in a different line and its calibration is off.

"3. But in this discussion, transmission line theory is under question."

I suggested using the Bird as an indicator of transmission line / load
match, period. This is based on balance in the directional coupler which
is usually good by design and factory adjustment. Many Bird users have
adjusted their lload matching networks for minimum reflected power
indication.

My allusion to the Bird was meant to show that it makes no difference if
you have two equal and opposite waves traveling in the reverse direction
on a line or no waves in that direction at all. A Bird wattmeter
operating properly should indicate zero reflected power.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
I suggested using the Bird as an indicator of transmission line / load
match, period. This is based on balance in the directional coupler which
is usually good by design and factory adjustment. Many Bird users have
adjusted their lload matching networks for minimum reflected power
indication.

As a data point, Using Bird wattmeters, the reflected power was subtracted
from the forward during the 75m mobile shootouts to determine the power
delivered to the mobile antenna.
--
73, Cecil http://www.qsl.net/w5dxp



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W5DXP wrote:
Ian White, G3SEK wrote:
So, I stand by exactly what I said: When discussing transmission-line
theory, the Bird's indications of forward and reflected power are (in
short) "part of the argument, not part of the answer".

Ian, if you can provide an example of standing waves (in a single source,
single feedline, single load system) without forward and reflected waves,
you can indeed discredit the Bird wattmeter.

That's utterly dishonest quoting. You should be ashamed of yourself.

You are perfectly aware that earlier in the same message, I said:

1. The Bird "wattmeter" does not in fact sense power. At the detailed
level, it senses voltages and currents in its internal transmission
line, and then sums and subtracts them to give RF voltages that the
diode detects. I repeat, there is no sensing of power as such, and no
detection of power as such.

My point is that all directional couplers DO work by sensing forward and
reflected waves of voltage and current BUT NOT WAVES OF POWER.

The inner workings of every directional coupler can be explained
*completely* in terms of waves of voltage and current. That includes
resistive bridges, Bruene bridges and parallel-line couplers (of which
the coupler in the Bird is a sub-class). They all work because E and I
waves are phasors, and the construction of the coupler makes them add in
one direction and subtract in the other. There's an example of a
detailed analysis, about the Bruene bridge but applicable in principle
to other types as well, at:
http://www.ifwtech.co.uk/g3sek/in-pr...-of.htm#bruene

Waveguide directional couplers work in very similar ways, but have to be
analysed in terms of forward and reflected E and H fields. That kind of
explanation also works for a waveguide circulator, the difference being
that some of the fields are inside a magnetic medium. A coaxial
circulator is more complex because it involves voltages and currents on
the line part and also E and H fields in the magnetic medium, but the
principle is the same.

This is all standard stuff that has been known for decades. Forward and
reflected waves of V and I (or E and H) give a complete explanation of
the directional properties of all such devices.

Let me turn the question around, Cecil: can you explain in detail how
any directional coupler gets its directional properties, using *only*
your concepts of power waves?


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek