Jim Kelley wrote:
I guess one could infer that that if G / C R / L, and R + jwL G +
jwC, then perhaps there are losses. I would only add that there are
probably also small currents in shunt distributed along the line.

If R 0 and G 0, then there are losses. The only time a line is
lossless is when R = G = 0 which, according to Reg, is only in my wet
dreams about circles on Smith Charts. :-) For real world transmission
lines at HF, (usually) R/Z0 G*Z0. When I was a member of the high
speed cable group at Intel, I remember test leads designed for R/Z0=G*Z0
but they were expensive special order devices.

We apparently are more successful at designing very good dielectrics
than in finding an economically feasible conductor with a couple of
magnitudes less resistance than copper. Thus our ordinary transmission
lines have a lot more series resistance than shunt conductance, especially
open-wire transmission lines in free space. :-)
--
73, Cecil http://www.qsl.net/w5dxp