Dave wrote:

Tom Ring wrote:

Tom, the original question is a single conductor transmission line. A
single conductor transmission line is used to feed a 'classic Windom'.

In that configuration, is it a G line?

For the uninitiated, including this questioner, what is a G line?


I don't believe a single bare wire will operate as a transmission line
in free space. It will radiate. G line, on the other hand, will not.
At least it won't radiate any more than a piece of coax. And it can be
used in reasonably normal situations, but no sharp bends. It is not
practical for HF, however. 70 cm would probably be as low as you would
want to go.

The quick description is that G line is a wire coated with a dielectric
to a specific thickness that is coupled to by a device resembling a
feedhorn on each end, where the horn is a flaring of the shield. As I
remember it, the dielectric discontinuity constrains the E field, and
hence the EM field. The losses are much lower than coax, on the order
of 5 dB per mile at 500 MHz.

For details see -

http://coldwar-c4i.net/G-Line/EE0860/p638.html

tom
K0TAR