Roy wrote -
If you have some other "rho" you want to
argue about, please call it something else.

===========================

- - - and while you are about it change the name of
the SWR meter.

On Wed, 03 Sep 2003 18:50:08 -0500, Cecil Moore
wrote:
Since you snipped my posting, I have no idea what it was all about.

Hi Cecil,

I didn't this time, and I doubt you are any further ahead. Perhaps
you suffer from the Motorola syndrome of confusion. ;-)

So, is your response to the offer of the bridge description
Yes?
or
No?

(Consult google to fill the short attention span problems.)

73's
Richard Clark, KB7QHC

So, do you want the bridge description or not?

Richard Clark, KB7QHC

============================

Rich, pleased to receive a message from you succinct
enough to read. ;o)

But it looks like there's at least two contestants who
have now vanished from the thread.

Keep stirring it up.

On Thu, 4 Sep 2003 00:38:54 +0000 (UTC), "Reg Edwards"
wrote:

So, do you want the bridge description or not?

Richard Clark, KB7QHC

============================

Rich, pleased to receive a message from you succinct
enough to read. ;o)

But it looks like there's at least two contestants who
have now vanished from the thread.

Keep stirring it up.


How do you mix an ingredient of one?

That query alone will bring in at least a dozen recipes. ;-)

Cecil Moore wrote:

wrote:
And yes, |rho| can be greater than unity for a passive load.

But the power reflection coefficient cannot be greater than 1.0
which is what the argument is all about.

Which is entirely consistent with my previous statement:
It follows that when rho is greater than unity, it is not 'physically
meaningful to separate the total power as the sum of the incident and
reflected power' so the equation
|rho| = Sqrt(Pref/Pfwd)
has no meaning.

I suppose one might phrase it as 'there is no such thing as a power
reflection coefficient' when it is not 'physically meaningful to
separate the total power as the sum of the incident and reflected
power'.

....Keith

Cecil Moore wrote:

Reg Edwards wrote:

Roy wrote -
If you have some other "rho" you want to
argue about, please call it something else.

- - - and while you are about it change the name of
the SWR meter.

Trouble is, (Z2-Z1)/(Z2+Z1) is not always equal to Sqrt(Pref/Pfwd)
What then?

The equality was always iffy when you don't take the absolute value.
But once you do, the equality may hold depending on the equations
you use to derive Pref and Pfwd.

Whether Pref or Pfwd represent something physically meaningful is
another question, also dependent on how you derive them.

....Keith

Keith wrote:
"I suppose one might phrase it as "There is no such thing as a power
reflection coefficient" when it is not physically meaningful to separate
the total power as the sum of the incident and reflected power so the
equatiomn:
[rho] = sq. rt. (Pref / Pfwd) has no meaning."

We don`t have a choice of options on a menu to select or reject from.
Reality is whatever it is and we accept it and describe it as best we
can.

Terman says on page 97 of his 1955 edition:
"{rho} = (SWR-1) / SWR + 1."

Power varies as the equare of the voltage, because when you increase the
volts you also automatically increase the amps (Ohm`s law). Thus, Terman
has a subscript at the bottom of page 97 which is relevant:
"The 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."

In my long rxperience, I`ve found it`s never profitable to argue with
Terman. He is as close to infallible as any wrirter I`ve ever read.

Best regards, Richard Harrison, KB5WZI

Cecil Moore wrote in message ...
Dr. Slick wrote:
And how do you explain the rho 1 for a passive network?
Shouldn't be possible. And neither should a negative SWR.

This seems to me to be somewhat akin to the fact that s11 and
rho can have different values at an impedance discontinuity
where a 'third power' is commonplace. Roy's 'third power' at
the load appears to be analogous to a re-reflection of some
sort as the inductive load tries and fails to dump energy
back into the Z0=68-j39 transmission line. A re-reflection
is another component of forward power.

The ratio of reflected Poynting vector to forward Poynting
vector is |rho|^2. In Roy's example, the total average
Poynting vector points toward the load indicating that
(Pz+ - Pz-) 0. That means |rho|^2 cannot be greater
than 1.0.


Cecil,

The ratio Pref/Pfwd is directly related to the ratio [rho].
Consider that after the absolute value brackets, the phase information
is gone. But since we are going to a ratio of average (RMS)
values OR peak values of power, it doesn't matter.

In other words, if you use V**2/R, the "V" can be either peak or
RMS, it doesn't matter, because it is a ratio. And of course, the "R"
doesn't matter either. And of course, the phase information is gone
with
the absolute value brackets.

If you agree that the Pref/Pfwd ratio cannot be greater than 1
for a passive network, then neither can the [Vref/Vfwd]= rho be
greater
than 1 either.

Some people wanna rewrite some books here.


Slick