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Old April 4th 06, 04:00 PM posted to rec.radio.amateur.antenna
Reg Edwards
 
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Default Phase shift and translines.

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.
----
Reg.


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Old April 4th 06, 05:45 PM posted to rec.radio.amateur.antenna
John Popelish
 
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Default Phase shift and translines.

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.
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Old April 4th 06, 07:20 PM posted to rec.radio.amateur.antenna
Reg Edwards
 
Posts: n/a
Default Phase shift and translines.


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


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