[G0HZU_JMR]

I suppose the other classic example is the half wave transmission line. As long as reasonable/sensible tline Zo and source/load impedances are used then it doesn't matter what the tline Zo is because (under steady state conditions) the load impedance at the far end appears at the source after having been rotated fully around one lap of the smith chart by the tline/cable. So it is almost as if the cable isn't there even if you change the cable Zo. So the source Z doesn't have to match the cable Zo here at all. The load seen by the source should look the same even if you could somehow magically change the cable Zo on the fly with a rotary control. This obviously assumes steady state conditions.