Dave Platt wrote:
The sort of "linearity" which Cecil seems to be referring to (if I
understand what he's written correctly) involves a completely
different sort of relationship. It's not current-vs-voltage, or
voltage-vs-current - it's current-vs-distance.

Assuming thin constant diameter wires with a constant Z0 and VF.

If the diameter of the wire changes, or Z0 changes, or VF changes,
the 'K' term in the cos(KX) expression changes. A change in a
constant does NOT produce non-linearity in a linear system. Just
because a wave slows down in a medium with a low VF doesn't mean
that the system has gone non-linear.
--
73, Cecil http://www.qsl.net/w5dxp