Well, about 60 years ago I was told to keep open wire at least 4X it's own
width from anything metallic. With the quibble that I have used very short
loops of WELL insulated wire to secure the line to an insulator I have found
that to be good advice for any style ladder line at any power level.
Being a typical ham; meaning cheap; I usually scrounge thrown away pieces of
plastic pipe from the newest subdivision in the area. A foot long chunk of 3/4
inch pipe with a couple of nail holes drilled on one end and a hole for a tie
of some sort on the other works great. But I usually use stainless deck screws
instead of nails. Or a couple of times I have used long self drilling screws to
attach the insulating pipe to metal objects of one sort or another.
And it should go without saying that you need to check the length of the
fasteners and what's behind what you are nailing or screwing something to
before you punch holes in plastic water pipes and the like.
I have had good luck with Radio Works baluns of all sorts, including the 4:1
variety - but there are homebrew solutions for that problem as well.
One note. There is a misapprehension that ladder line either won't radiate or
it won't radiate (or pick up noise) if it has a 180 degree twist every 10 feet
or so. Let me state unequivocally that any sort of twin lead will radiate, the
wider the spacing between the wires the more it will radiate, and anything that
unbalances the line will increase the amount of radiation. Twisting the wire
MAY result in cancellation - and it MAY reduce the amount of noise pickup. But
it's likely to have no effect at all.
Bottom line - keep your eyes open, stand it well away from anything that can
couple to it, and it will do you a good job.
73 Pete Allen AC5E
--
Never squat with your spurs on
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