"Bob Myers" wrote in news:MmdPh.1809
:


"Dave Oldridge" wrote in message
9...
If the lossless transmission line (obviously no such animal exists)
were
tuned with a lossless tuner, then VSWR would not matter at all.

Dave, I'm pretty sure I know what you mean here, but it should
be noted that this isn't entirely true. The line would have to have a
couple
of other characteristics besides being simply "lossless" for VSWR
not to matter at all.

Not if there's a lossless tuner.

The problem, of course, is that a VSWR of other than 1:1 implies
(by definition!) that the voltages and currents along the length of
the line are not constant; there are cyclic variations in each, with
maxima and minima located at half-wavelength intervals (that's
the whole "standing wave" thing in the first place, right?).
Particularly in high-power situations, it is possible for the maxima
to exceed the ratings of the source or of the line itself.

In which case it's not truly "lossless" (and after breakdown becomes VERY
lossy).



--
Dave Oldridge+
ICQ 1800667