Richard Clark wrote:
James barrett wrote:
Why is the twin lead consideres less
lossy than coax?

All loss is in the bulk of the conductor. When comparing the two,
twin lead usually has more bulk = less loss.

The Z0 of the feedline has a lot to do with the I^2*R
losses in the line, one of the main sources of feedline
loss. Ifor = Vfor/Z0, so the higher the Z0, the lower
the current.

Coax has Z0s less than 100. Parallel lines usually have
Z0s greater than 100. That's a major reason that parallel
lines have lower losses.

It is also easier to build parallel lines with lots of
air dielectric, thus reducing dielectric losses.
--
73, Cecil http://www.w5dxp.com