"Peter O. Brackett" wrote in message thlink.net...
Slick:

[snip]
If you believe that there are theoretically no
reflections in a conjugate match, then with

Zl=50+j10 and Zo=50-j10,

the conjugate equation correctly cancels the reactances
giving no reflections, while the non-conjugate still
incorrectly gives a magitude (non zero) for rho.

Slick
[snip]

Oh yes here are voltage reflections at a conjugate match!

Simply put as waves pass across the transition from an impedance
of Zo to an impedance of conj(Zo) they are crossing a boundary
with an impedance discontinuity. Zo on one side and conj(Zo)
on the other side is definitely discontinuous! Unless of course,
Zo = conj(Zo) which occurs only when Zo is real.

There will always reflections at such an impedance
discontinuity where an impedance faces its' conjugate.



I disagree completely. The theoretical impedance of a resonant
series L and C (which is lossless) is zero. So in a conjugate
match, where they cancel out, in an ideal loss-less world, it
would be equivalent to the series C and L not being there at all,
with the source and load 50 ohms free to pass max. power delivered to
the load.




If an impedance Zo faces its' conjugate conj(Zo) then there will be
no "power reflections", but there will in general be voltage reflections,


??? if the square of the magnitude of the voltage RC is the power RC,
then your statement is incorrect. And rho (magnitude of Voltage RC) is the
square root of the Power RC.




i.e. "classical" rho = (Z - Zo)/(Z + Zo) is not zero at a conjugate match.


That's why it is incorrect for complex Zo.



I also believe that this is "Mother Nature's" reflection coefficient
for it is exactly what she uses as she lets the waves propagate
down her lines of surge impedance Zo following her partial differential
equations at every point along the way. At every infinitesimal
length of line all along it's length the waves are passing from a
infinitesimal region of surge impedance Zo to the next infinitesimal
region of surge impedance Zo and there are no voltage reflections
anywhere along that [uniform] line, although if the line is not lossless
there will be energy lost as the wave progresses.


Maybe "Mother Nature" should take a Les Besser course...


Slick... On another whole level it simply does not matter which defiinition
of the reflection coefficient one uses to make design calculations though,
as
long as the definition is used consistently throughout any calculations.


I totally disagree again:

Did you read Williams' data?


The data follows:

Note: |rho1*| is conjugated rho1, SWR1 is for
|rho1*|, |rho2| is not conjugated and SWR2 applies
to |rho2|

X0.......|rho1*|..SWR1.....|rho2|..SWR2
-250..... 0.935...30.0.....1.865...-3.30
-200..... 0.937...30.8.....1.705...-3.80
-150..... 0.942...33.3.....1.517...-4.87
-100..... 0.948...37.5.....1.320...-7.25
-050..... 0.955...43.3.....1.131...-16.3
-020..... 0.959...47.6.....1.030...-76.5
-015..... 0.960...48.4.....1.010...-204
-012..... 0.960...48.9.....0.997....+/- infinity
-010..... 0.960...49.2.....0.990....+305
-004..... 0.961...76.3.....0.974....+76.3
0000..... 0.961...50.9.....0.961....+50.9

The numbers for not-conjugate rho are all over the
place and lead to ridiculous numbers for SWR. It
is also obvious that for a low-loss line it
doesn't matter much. But values of rho greater
than 1.0, on a Smith chart correspond to negative
values of resistance (see the data).



Excellent work William. You are also showing how
a rho1 leads to ridiculous numbers for the equation:

SWR = (1 + rho)/(1 - rho)

The non-conjugate equation simply cannot handle
complex Zo.

Some people think we should throw out the SWR formula
completely, but this is complete nonsense, of course.

SWR = (1 + rho)/(1 - rho) works for 0=rho=1,
for very good reason, as it applies to passive networks only.

And the conjugate will always give 0=rho=1,
even with a complex Zo.


Slick

Slick:

[snip]
I disagree completely. The theoretical impedance of a resonant
series L and C (which is lossless) is zero. So in a conjugate
match, where they cancel out, in an ideal loss-less world, it
would be equivalent to the series C and L not being there at all,
with the source and load 50 ohms free to pass max. power delivered to
the load.
[snip]

Which is exactly what happens for all energy passing through at
the resonant frequency of the series LC!

And for instance if you are testing with a sinusoidal generator at
that frequency that is exactly what you will observe.

Of course if you are testing with a broad band signal rather
than a sinusoidal signal lots of much more interesting stuff
happens. That all can be calculated simply by using the
full functional descriptions of the network/transmission
system, i.e. assuming Z = Z(p) where p = s + jw, etc, etc...

[snip]
??? if the square of the magnitude of the voltage RC is the power RC,
then your statement is incorrect.
[snip]

To which voltage reflection coefficient do you refer? :-)

No! The square of the magnitude of the voltage reflection coefficient is
not,
in general, equal to the power reflection coefficient.

[snip]
That's why it is incorrect for complex Zo.
[snip]

Slick, no "correctly" defined reflection coefficient is "incorrect".

There can easily be an infinity of different "correct" reflection
coefficients so defined,
and none is "incorrect" so long as no incorrect conclusions are drawn from
their use.

The only "incorrect" ones are the reflection coefficients that are not
defined based upon simple non-singular linear combinations of the electrical
variables i and v.

Slick, your view of the reflection coefficient world is far too narrow!

Widen your horizons, there is more than one way to go to hell, and
chosing a particular definition of a reflection coefficient and forcing
all others to believe in it is nothing short of bigotry!

[snip]
Maybe "Mother Nature" should take a Les Besser course...
[snip]

I am sure that Dr. Besser is an honorable and accomplished man despite
his obviously narrow views of "waves".

[snip]
I totally disagree again:

Did you read Williams' data?
[snip]

Yes I "scanned" it and lost interest quickly, because of the gratuitous
use of mind boggling numerical tables in ASCII text on a newsgroup
posting!

I am sure that William did a lot of work whilst typing in those long
strings of numbers without error. Good work William!

Hey I'll scan in and post a listing of a couple of thousand lines of the Zo
versus frequency of 18,000 feet of plastic insulated AWG 24 wire if that
will help. I've got hundreds and hundreds of pages of such data! :-)

[snip]
Excellent work William. You are also showing how
a rho1 leads to ridiculous numbers for the equation:

SWR = (1 + rho)/(1 - rho)

The non-conjugate equation simply cannot handle
complex Zo.

Some people think we should throw out the SWR formula
completely, but this is complete nonsense, of course.

SWR = (1 + rho)/(1 - rho) works for 0=rho=1,
for very good reason, as it applies to passive networks only.

And the conjugate will always give 0=rho=1,
even with a complex Zo.
[snip]

Hey, again your view of rho and VSWR is too narrow.

Ask yourself what is the meaning of SWR in that formula
when rho is complex and SWR is complex!

Actually if you let your mind expand a little beyond your
narrow view of things you will find that complex SWR can
have a physical and useful meaning as well.

--
Peter K1PO
Indialantic By-the-Sea, FL

"Peter O. Brackett" wrote in message
link.net...
Slick:

Hey, again your view of rho and VSWR is too narrow.

Ask yourself what is the meaning of SWR in that formula
when rho is complex and SWR is complex!


how can swr be complex... in my book it is:

SWR=(1+|rho|)/(1-|rho|)

so swr can't be complex.

"Peter O. Brackett" wrote in message hlink.net...
Slick:

[snip]
I disagree completely. The theoretical impedance of a resonant
series L and C (which is lossless) is zero. So in a conjugate
match, where they cancel out, in an ideal loss-less world, it
would be equivalent to the series C and L not being there at all,
with the source and load 50 ohms free to pass max. power delivered to
the load.
[snip]

Which is exactly what happens for all energy passing through at
the resonant frequency of the series LC!

And for instance if you are testing with a sinusoidal generator at
that frequency that is exactly what you will observe.

Of course if you are testing with a broad band signal rather
than a sinusoidal signal lots of much more interesting stuff
happens. That all can be calculated simply by using the
full functional descriptions of the network/transmission
system, i.e. assuming Z = Z(p) where p = s + jw, etc, etc...



Well, of course i assume the conjugate match to occur at ONE frequency,
and with a small signal sine wave.




[snip]
??? if the square of the magnitude of the voltage RC is the power RC,
then your statement is incorrect.
[snip]

To which voltage reflection coefficient do you refer? :-)

No! The square of the magnitude of the voltage reflection coefficient is
not,
in general, equal to the power reflection coefficient.



Nope! Page 16-2 of the 1993 ARRL: rho=sqrt(Preflected/Pforward)

Look it up yourself, don't take my word for it.





The only "incorrect" ones are the reflection coefficients that are not
defined based upon simple non-singular linear combinations of the electrical
variables i and v.


I don't think you know what you are typing about here..



Slick, your view of the reflection coefficient world is far too narrow!

Widen your horizons, there is more than one way to go to hell, and
chosing a particular definition of a reflection coefficient and forcing
all others to believe in it is nothing short of bigotry!



Believe what you will... I ain't forcing anyone to accept anything!
I will tell you what respected authorities have written, though.

Jesus, dude. Do you want me to agree with you even when i think you
are incorrect?

Or would you prefer me to be honest?


[snip]
Maybe "Mother Nature" should take a Les Besser course...
[snip]

I am sure that Dr. Besser is an honorable and accomplished man despite
his obviously narrow views of "waves".



YOU are the one with the narrow views. Besser's courses are like
$1,200 a head. Do you think companies would pay him to steer them wrong?

Please!




Yes I "scanned" it and lost interest quickly, because of the gratuitous
use of mind boggling numerical tables in ASCII text on a newsgroup
posting!

I am sure that William did a lot of work whilst typing in those long
strings of numbers without error. Good work William!



Lost interest, or don't want to look at information that you disagree
with?



[snip]
Excellent work William. You are also showing how
a rho1 leads to ridiculous numbers for the equation:

SWR = (1 + rho)/(1 - rho)

The non-conjugate equation simply cannot handle
complex Zo.

Some people think we should throw out the SWR formula
completely, but this is complete nonsense, of course.

SWR = (1 + rho)/(1 - rho) works for 0=rho=1,
for very good reason, as it applies to passive networks only.

And the conjugate will always give 0=rho=1,
even with a complex Zo.
[snip]

Hey, again your view of rho and VSWR is too narrow.

Ask yourself what is the meaning of SWR in that formula
when rho is complex and SWR is complex!



Sigh... rho is the MAGNITUDE of the RC, so it isn't complex.

And SWR is never complex! And a negative SWR is pretty
meaningless!

If you want to rewrite the RF books, good luck.


Cheers,

Slick

Dr. Slick wrote:

"Peter O. Brackett" wrote:
There will always reflections at such an impedance
discontinuity where an impedance faces its' conjugate.

I disagree completely. The theoretical impedance of a resonant
series L and C (which is lossless) is zero. So in a conjugate
match, where they cancel out, in an ideal loss-less world, it
would be equivalent to the series C and L not being there at all,
with the source and load 50 ohms free to pass max. power delivered to
the load.

Better be careful. Did you just assert that you can change
the SWR on a feedline by forming a conjugate match at the source?
All Peter is saying is that the VSWR on the feedline will not be 1:1
if Z-complex-load differs from the purely resistive Z0 of a lossless
line. For a lossless line, there is nothing you can do at the source
to change the SWR at the load.

However, if the line is lossless, you can achieve maximum power
transfer anyway even in the face of a high SWR.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote in message ...

I disagree completely. The theoretical impedance of a resonant
series L and C (which is lossless) is zero. So in a conjugate
match, where they cancel out, in an ideal loss-less world, it
would be equivalent to the series C and L not being there at all,
with the source and load 50 ohms free to pass max. power delivered to
the load.

Better be careful. Did you just assert that you can change
the SWR on a feedline by forming a conjugate match at the source?
All Peter is saying is that the VSWR on the feedline will not be 1:1
if Z-complex-load differs from the purely resistive Z0 of a lossless
line. For a lossless line, there is nothing you can do at the source
to change the SWR at the load.


As usual, your sentences don't make too much sense, which is probably
why you go one with your record-breaking threads.
Maybe you actually agree with people when you argue with them...
well, we could all be accused of that one.

However, if the line is lossless, you can achieve maximum power
transfer anyway even in the face of a high SWR.


If Zo=50-j5 and Zload=50+j5, you will have a conjugate match,
and max power delivered to the load.


Slick