wrote in message
I tried to post a mention of a very odd feedline called the "G-line"
Two attempts and google ate both of them.

It is a true single conductor UHF feedline.
It isn't perfect, but has a low loss.
It "leaks" and in some situaiton that is a benifit.

In my final year of undergraduate engineering, I did a project for a
professor on a surface wave transmission line. While my project was not a
stellar success, it was interesting reserach. One application he had in mind
was to run a line beside a railway track and use time domain reflectometry
to track the location of trains. The idea was that the large train body
would affect the dielectric and electrostatic environment near the line,
cause greater leakage and the radiation would be reflected back onto the
line.

A surface wave transmission line is a waveguide, the complement of a
cylindrically enclosed waveguide.

Tom