Bob, I actually twist mine 3 or 4 times per 10 ft. length.
I had better luck with stranded, Barry had better luck with solid, but in
the end, the real trick (for survival) is to always use strain-relief,
regardless of the type of conductor. There are several different center
insulators available that achieve this, including one from Ten-Tec.
As always, Sinisa is fully correct, though for short runs it sure is a lot
simpler just to use ladderline. In practice I have had installations with
true openwire and with ladderline and for runs up to about 25m (75 ft.), I
didn't "feel" any difference in performance - regardless of what the theory
predicts.
For the purists, especially those desiring to run high power into short
radiators, the feedline and the radiator should be one piece (per side). In
other words, don't solder the open wire to the dipole halves - run each leg
of the dipole all the way to the matchbox and use the appropriate clip-on
spreaders. This is especially important if you use highly shortened lengths
for the dipole on low bands (which is often the case).
But as Bob pointed out, with wx changes, the ladderline is more conceptacle
to impedance change than true open wire and one must simply twist the knobs
on the tuner more often. In many cases this is a good compromise for lazy
people like me.
For portable operations where the antenna is put up and taken down often,
the ladderline wins hands down for ease of use.
End of theory, now on the light side (true story):
My first home-brew openwire feeder was built in 1962 using stolen plastic
hair curlers from my two sisters. I was 14 and just newly licensed. My mom
still didn't understand much about ham radio. My sisters complained that I
had used all their hair curlers and I got punished with "House arrest".
Since this ham thing was quite new, mom had no idea that house arrest for a
ham was a reward and not a punishment (hi). Had to buy my sisters new
curlers, though.
73
Rick
DJ0IP / NJ0IP
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