Reg Edwards wrote:
The phase shift in degrees along a transmission line is a very
fixed
quantity. Regardless of how it is used or what sort of circuit it
is
in.

The only way to change it is to change line length or frequency.

(continuing on)

This is the property that allows us to distinguish whether a black
box
contains a length of transmission line or an approximation of that
made of lumped series inductors and shunt capacitors. The
approximation will mimic a transmission line, only if the impedances
driving and loading it are in a range, and only over some frequency
range. The approximation of a transmission line is good, only under
some conditions.
===================================
Yes. An artificial line of series inductors and shunt capacitors is a
low pass filter. The propagation delay in time is relatively constant
until near the cut-off frequency when it increases rapidly.

At frequencies beyond cut-off it stops working.

A true transmission line doesn't have a cut-off frequency.
----
Reg