RF Cafe Software
About RF Cafe
1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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Dear L. Joseph and RF Café readers,
In regards to your Transmission Line Impedance question. The length of the transmission line can be largely ignored here. A theoretical lossless transmission line will only rotate the terminating impedance around on the same VSWR circle. You would only need to take the transmission line length into account if it were long enough for its attenuation characteristics to become significant.
The direct answer to your question is yes, for (your) two termination impedances the VSWR ratio will always be 1.33 regardless of the transmission line impedance. As long as the transmission line impedance stays lower than your lowest termination impedance.
I used Mathcad for the equations, but you should be able to make spread sheet calculation to do the job. You’ll find it interesting to play with the line impedance. It will cause the VSWR ratio to change when it is between the two termination impedances.