To anybody interested.

We have a HF Transmitter + 50-ohm coax + SWR meter + Tuner + Feedline of any
Zo + Antenna.


Suppose it is all tuned-up and ready to go. The transmitter is loaded with
exactly 50-ohms resistive.


Now change the 50-ohm coax to shorter length of 75-ohm Zo.


As everybody agrees (after perhaps a little meter recalibration) the SWR
meter indication will not change. BUT THE TRANSMITTER WILL NOW BE
INCORRECTLY LOADED.


Where does the inconistency lie ? Does it lie in the change in effective
source impedance?