I remember one case where making coax was done and was appropriate. It
was a line that was several inches in diameter and probably no more than
20 meters long. The purpose that it served was to "feed" an end-fire
array of loop receiving antennas (along the line's length). The reason
to use the line was to have a VF that was as close to 0.99 as possible
so as to phase the distributed elements as optimally as possible.
Attenuation and power had nothing to do with the issue.
The result was a unidirectional pattern. One in each direction
depending on which end one connected to. Three of these fellows (and
six connections) made a reasonable direction finder with an
instantaneous beam every 60 degrees.
Life is much too short for one to use anything other than Heliax (or
TV cable) for the "normal" radio uses.
73 Mac N8TT
P.S. The fellows who replicated the Luxemburg effect with extremely
high power were said to have made their transmission lines out of
irrigation pipe. They must have had much more time than money.

--
J. Mc Laughlin - Michigan USA
Home:

"Ian White, G3SEK" wrote in message snip

Except for those special-purpose applications, it really isn't worth
the
trouble. It's easier to turn detective and find surplus sources of
hardline such as 50-ohm Heliax (used at cellular sites world-wide) or
the 75-ohm hardline used in the USA for cable TV.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek