In message , Tom Bruhns
writes
Aren't you glad we don't generally have to worry about nonlinearities
in the propagation of our waves (through space or along transmission
lines)? (Well, maybe you do if you aren't using a reasonable model
for your lines...) Following is from an e-newsletter I get:

But propagation is non-linear through the ionosphere. The velocity
varies with the electron density. Otherwise the wave wouldn't bend.

Mike
--
M.J.Powell