On Tue, 27 Sep 2005 02:04:46 GMT, Cecil Moore wrote:


The transmission line length must only be long enough such that
the V/I ratio is forced to the Z0 value. According to some pretty
smart guys I asked, that's about 2% of a wavelength.

Cecil, do you have some quantitative explanation / support for this?

The treatments that I have seen of transmission line tuners where
different Zo lines are directly connected do not suggest corrections /
tolerances of the type you imply.

(IIRC, Terman discusses a fringing capacitance as a means of allowing
for a physical discontinuity.)

I am not asking whether or not field conditions (and V/I on the
conductors) immediate to the discontinuity are not Zo of either of the
lines, just where has the 2% of a wavelength come from?

Owen
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