Thread: Reflection Loss
View Single Post
  #8   Report Post  
Old March 6th 06, 10:49 AM posted to rec.radio.amateur.antenna
Richard Harrison
 
Posts: n/a
Default Reflection Loss

Owen Duffy wrote:
"Richard, formula 4-22b calculates the magnitude of the reflection
coefficient from SWR, it is not possible to calculate the reflection
coefficient (as you say) in the general case since you lack phase
information."

Phase information is not needed. It is true that the reflection
coefficient is a vector ratio of the reflected voltage to the incident
voltage at the load but this does not affect conversion of the
reflection coefficient to the SWR.

Reactance at the load has the same effect as adding a same-impedance
line (of particular length) between the generator and load. This only
shifts the SWR pattern on the line, but in a practical line has no
effect on the minima and maxima on the line.

SWR is simply the ratio of the maximmum amplitude to the minimum
amplitude of voltage (or current) on the line in a particular region of
the line. A maximum is displaced by 1/4-wave from a minimum.

Phase information is irrelevant to conversion between reflection
coefficient and SWR. That`s why Terman didn`t include it.

Best regards, Richard Harrison, KB5WZI