Tom, unfortunately 6 years is not too bad for some of the multi-strand
antenna wire. In fact we have had some embarrassing experience with it
and have replaced quite a bit at our expense(and would happily do yours
if you got it from us).
The story is this:- the ideal copper clad steel for antennas in larger
gauges is 30% copper and 70% HS(high strength), tempered steel. It, like
the old pole to pole telephone wires(which were both 40 and 30% in
various places), would last darn near forever - in fact some of it I've
seen still hangs abandoned on poles in many places in the west, upper
Michigan, and elsewhere(green and black with various copper oxides etc.,
but good as gold). It was usually 10 or 12 AWG solid. Up to 18 gauge it
was also just as durable.
Smaller gauges were drawn through smaller dies down to gauges between 40
and 50. If temper and other factors are not carefully controlled and
observed, microscopic stress cracks occur in the copper layer, and when
19 wires are laid up into a, say, a 14, 16, or 18 gauge finished wire,
trapped moisture with the whole will cause some degree of rust in the
tiny cracks. The wire is destroyed at a rate related to the
environment(salt air, acid rain, even plain rain, will eventually do it
Several remedies are possible - lower temper of the larger wire to lower
the machine hardening action that causes the cracks; or using 40% copper
for less risk; or tinning the strands before or after drawing; or
combinations thereof. The remedy of jacketing is used as well, and with
the right jacket, it is very successful. We've tried 'em all.
Seven strand copperclad steel is a traditional solution, too, for the
obvious reason that its 22 or 21 gauge members used in 14 and 12 gauge
composites have been drawn through fewer operations than that of gauges
in the 30's.
The best stranded copper clad steel(CCS), or copper, or any material will
most probably not last as long as solid CCS, for any or all of the above
reasons. On the other hand there are many criteria besides longevity that
may be important to the user - ease of installation being the most common
to the amateur radio user. There are applications that reach to the
ultimate flexibility of the very popular "FLEX-WEAVEtm"
(Davis RF). We all need to make our own choice.
We have made long wires over the years using 14 and 12 gauge solid CCS
that saw the poles fall down without wire failure, and would do it again
in a minute for the same application. We've put up a wide variety of
shorter dipoles using 18 gauge CCS, that, were easy to put up, and so
cheap that it was easier to toss them than save them when no longer
needed. On the other hand, the stranded wires are without equal for
complex, self adjusting, portable and suitcase models.
Drawing the rambling to an end, if 6 years was a bad deal in the lengths
you used, go for solid 14 AWG CCS, flood every single scratch of
installation twist and wrap with solder, put a tad of marine grade axle
grease on the loop in contact with any ceramic or porcelain insulator
used(nothing for plastic types), and forget til the towers fall.
Press Jones, N8UG, The Wireman, Inc., Landrum, SC 29356
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