Richard Clark wrote:
Feelings hmmm? Yeah, I suppose I get pretty emotional over your wild
nonsense of sqrt of 1 could be -1.

It is well known that (-1)^2 = +1. You sometimes quote Johnson as a
reference. From Johnson, section 1.6, page 16: "The ratio 'k' is called
the reflection coefficient." "The terminating impedance is zero at this
end, provided the internal resistance of the generator is negligible;
hence for the generator end"

the reflection coefficient, "k(g) = -Z0/Z0 = -1"

--
73, Cecil http://www.qsl.net/w5dxp



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wrote:

Cecil Moore wrote:

wrote:
It is only true for the special case of single frequency sinusoidal
waveforms.

Which is the general case for a key-down ham transmitter.

It is indeed the usual case, but limiting your thinking to the
usual case reduces your opportunity for understanding.

Can you give me an example of a key-down CW transmitter that is not
single frequency sinusoidal waveforms?
--
73, Cecil http://www.qsl.net/w5dxp



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On Tue, 30 Sep 2003 08:41:06 -0500, Cecil Moore
wrote:

Richard Clark wrote:
Feelings hmmm? Yeah, I suppose I get pretty emotional over your wild
nonsense of sqrt of 1 could be -1.

It is well known that (-1)^2 = +1.

You cannot show that any two powers used to compute Rho are negative
to fulfill this shift of your logic.
I probably should have said rho^2 = Pref/Pfwd. When Pref = Pfwd,
rho can be plus or minus one.
Rho can never be plus or minus one on the basis of sqrt (Pref/Pfwd).
To insist otherwise is the joke that gets me emotional with the
chuckles and gets you into a huff claiming you can't talk about it.

You sometimes quote Johnson

Hi Cecil,

This again demonstrates how you are an unreliable correspondent. You
ascribe an action to me that is simply not true.
From Johnson, section 1.6, page 16:
Is NOT a citation. Who is Johnson? Certainly you feel free to
associate my name with him, but Dr. Samuel Johnson never said any such
thing in his life. Note that I always give full names and complete
titles to my citations - unreliable correspondents are lazy
correspondents who throw statement after statement against the wall
until one sticks and they call that their authority. Read any of Gene
Nygaard's postings for boundless examples.

Cecil, this laziness of yours is part and parcel to your poor
recitations and flawed logic. You squirm to pull away from your
absurd example of imparting direction of power flow based on an
erroneous concept of finding negativity extracted from a dependant
variable based on negative power ratios. You are attempting to recast
that argument into other equivalent terms of Rho, while maintaining
this charade of that same sign inversion supporting your un-referenced
direction issue. You cannot demonstrate the direction flow sign being
constructed from a negative Rho on the basis of sqrt(Pref/Pfwd).

If you feel you cannot communicate with me, you certainly have that
right; but for this issue I am not the only one and it is not due to
my lack of communication ability (as I am probably the only one here
credentialed to that matter).

73's
Richard Clark, KB7QHC

Richard Clark wrote:
You cannot show that any two powers used to compute Rho are negative
to fulfill this shift of your logic.

It doesn't require either power to be negative. All it requires is a
short circuit. +1 simply has two square roots. rho = -1 for a short
circuit and rho = +1 for an open circuit. All (rho = -1) requires is a
short at the end of a transmission line as explained in _Transmission_
Lines_and_Networks_, by Walter C. Johnson when he was chairman of the
Princeton EE Dept. Here's how he calculated rho for a short:

rho = (Z1-Z0)/(Z1+Z0) = (0-Z0)/(0+Z0) = -Z0/Z0 = -1

So your argument is with Dr. Johnson whom I am merely quoting. The
(rho = -1) simply indicates a 180 degree phase shift in the reflected
voltage at the short.

From Johnson, section 1.6, page 16:
Is NOT a citation. Who is Johnson?

It doesn't surprise me a bit that you are ignorant of Johnson. In 1950,
his book was one of the series of McGraw-Hill Electrical and Electronic
Engineering Series with Terman as the consulting editor and containing
textbooks by Kraus, Skilling, Terman, and others.

... it is not due to
my lack of communication ability (as I am probably the only one here
credentialed to that matter).

Must be really difficult to communicate when you are so special as to
be the "only one here" who is "credentialed to that matter". Many of
the posters to this newsgroup have written books and articles which
I find to be communicated rather well.
--
73, Cecil http://www.qsl.net/w5dxp



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On Tue, 30 Sep 2003 12:48:32 -0500, Cecil Moore
wrote:

Richard Clark wrote:
You cannot show that any two powers used to compute Rho are negative
to fulfill this shift of your logic.

Walter C. Johnson when he was chairman of the
Princeton EE Dept. Here's how he calculated rho for a short:

rho = (Z1-Z0)/(Z1+Z0) = (0-Z0)/(0+Z0) = -Z0/Z0 = -1

So your argument is with Dr. Johnson whom I am merely quoting.

No my argument is with your perversion of yet another source in your
vain attempt to draw a faulty conclusion in applying direction as the
basis of the -1 drawn from your observation
I probably should have said rho^2 = Pref/Pfwd. When Pref = Pfwd,
rho can be plus or minus one.
I notice you continually flee from your assertion to prove a different
statement "Dr. Johnson" made.

It doesn't surprise me a bit that you are ignorant of Johnson.

The unreliable correspondent once again, in laziness, again fails to
offer which Johnson. Presumably Walter, but you don't say, and
several Dr. Johnsons have been employed as sources in this group.
Your characteristic failure to attend boundary conditions is
consistent with your inability to preserve your assertion that somehow
a negative association is made with the sqrt(Pref/Pfwd) and that it
proves a change of direction (wholly unsubstantiated by any but your
own Johnson).

Must be really difficult to communicate when you are so special as to
be the "only one here" who is "credentialed to that matter". Many of
the posters to this newsgroup have written books and articles which
I find to be communicated rather well.

And with whom you have such difficulty communicating with.

73's
Richard Clark, KB7QHC

Cecil, W5DXP wrote:
'I probably should have said rho^2 = Pref / Pfwd, rho can be plus or
minus 1."

Terman mentions a power ratio at the bottom of page 97 of his 1955
edition:
"This definition of standing-wave ratio is sometimes called voltage
standing-wave ratio (VSWR) to distinguish it from the standing-wave
ratio expressed as a power ratio, which is (Emax / Emin) squared.

Best regards, Richard Harrison, KB5WZI

Cecil Moore wrote:
Consider the following:

Source---50 ohm feedline---+---1/2WL 150 ohm---50 ohm load

Isn't the 50 ohms that causes rho=0 on the 50 ohm feedline
simply the V/I ratio at point '+'?

The nature of things a point '+' are undefined, so I can't address
that. But according to the way you defined the problem, the
characteristic impedance of the 50 ohm feedline is 50 ohms. That sets
the V/I ratio. The impedance is determined by the distributed
capacitances and inductances of the transmission line - not by the
voltage you put across it. Is there some other way I'm supposed to look
at it?

73, Jim AC6XG

Cecil Moore wrote:
Isn't the 50 ohms that causes rho=0 on the 50 ohm feedline
simply the V/I ratio at point '+'?

I see now. Your interested in something else here, I think. The rho
for the whole network which includes both impedance discontinuities is
indeed zero. We've talked about that before. But the rho for the
single discontinuity at '+' is not equal to zero. The reflected
impedance (the load impedance, repeated a half wavelength away) is not
considered in the evaluation of rho at '+'. It is the characteristic
impedance of the line that is considered. You would agree, no?

73, Jim AC6XG

Cecil Moore wrote:
All (rho = -1) requires is a
short at the end of a transmission line as explained in _Transmission_
Lines_and_Networks_, by Walter C. Johnson when he was chairman of the
Princeton EE Dept. Here's how he calculated rho for a short:

rho = (Z1-Z0)/(Z1+Z0) = (0-Z0)/(0+Z0) = -Z0/Z0 = -1

So your argument is with Dr. Johnson whom I am merely quoting. The
(rho = -1) simply indicates a 180 degree phase shift in the reflected
voltage at the short.

Quite false. Negation is not simply a 180 degree phase shift.

And if Walter C. Johnson is worthy of the respect he receives
here, he has certainly never said it is.

....Keith

Jim Kelley wrote:

Cecil Moore wrote:
Consider the following:

Source---50 ohm feedline---+---1/2WL 150 ohm---50 ohm load

Isn't the 50 ohms that causes rho=0 on the 50 ohm feedline
simply the V/I ratio at point '+'?

The nature of things a point '+' are undefined,

Nope, they are not. The V/I ratio at '+' equals 50 ohms.

so I can't address
that. But according to the way you defined the problem, the
characteristic impedance of the 50 ohm feedline is 50 ohms. That sets
the V/I ratio. The impedance is determined by the distributed
capacitances and inductances of the transmission line - not by the
voltage you put across it. Is there some other way I'm supposed to look
at it?

There are no reflections on the 50 ohm feedline because it "sees" 50
ohms at point '+'. The 50 ohms seen at point '+' is a V/I ratio equal
to 50 ohms. So V affects rho. And rho causes that same V? See
the circular logic?
--
73, Cecil http://www.qsl.net/w5dxp



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