Keith Dysart wrote:
So sometimes a 600 to 100 ohm discontinuity
produces a 36.6 degree phase shift and sometimes
it produces a 22.7 degree phase shift (and probably
any value in between).

Yes, of course - nobody said the phase shift wasn't
a variable. Why would you expect it to be a constant?
It is a variable that depends upon the phase of the
component forward and reflected waves.

I suggest that "work[ing] up the phasor diagrams of
the component voltages (or currents) at the junction
where rho = (600-100)/(600+100) = 0.7143" will
not be useful for predicting the phase shift.

It will be useful for reporting that particular phase
shift. If other conditions change, that phase shift
will change. What is unexpected about that?
--
73, Cecil http://www.w5dxp.com

On Dec 7, 4:09 pm, Cecil Moore wrote:
Keith Dysart wrote:
So sometimes a 600 to 100 ohm discontinuity
produces a 36.6 degree phase shift and sometimes
it produces a 22.7 degree phase shift (and probably
any value in between).

Yes, of course - nobody said the phase shift wasn't
a variable. Why would you expect it to be a constant?
It is a variable that depends upon the phase of the
component forward and reflected waves.

I suggest that "work[ing] up the phasor diagrams of
the component voltages (or currents) at the junction
where rho = (600-100)/(600+100) = 0.7143" will
not be useful for predicting the phase shift.

It will be useful for reporting that particular phase
shift. If other conditions change, that phase shift
will change. What is unexpected about that?

You implied that you were going to compute it
using just rho, which would mean it would be
constant for any pair of impedances.

With more inputs, it might be possible to
compute a number that, when added to the
actual electrical lengths of the lines, will
result in 90 degrees. I expect the algorithm
to be fairly complicated.

Of course, one can always just say it is equal
to 90 minus the sum of the electrical lengths
of the lines, though if there were two or more
impedance discontinuities, it might be difficult
to apportion the difference between them.

I await the algorithm.

....Keith

Keith Dysart wrote:
You implied that you were going to compute it
using just rho, which would mean it would be
constant for any pair of impedances.

No, I did not. Rho can be constant but the phase
angle of the incident voltage changes with
position. Therefore, the phase angle of the
reflected voltage changes with position.

This subject is already covered in my energy
analysis article at:

http://www.w5dxp.com/energy.htm
--
73, Cecil http://www.w5dxp.com