An alternative to the stretching exercise would be to purchase hard
drawn copper wire, here are the specifications:
http://www.cmewire.com/catalog/sec02-bcc/bcc-01.pdf. BTW, I used to
purchase copperweld however it held so terribly at P40A that I quite
using it.
John KK9A
Bob Shohet, KQ2M wrote
Hi Jim,
”A major advantage of using stretched wire is that un-stretched copper
will stretch under tension over years. Before changing to stretched
wire,”
I have seen you mention this a number of times in the past and I have
been meaning to ask you some questions about it.
My non-engineering understanding of wires and stretch is that a given
wire after being subject to variable strength forces over a given
period of time, will stretch only so far before it breaks. Assuming
that that is conceptually correct, let’s say that we have two wires –
Wire A and Wire B. Wire A has been pre-stretched before being put up
and is now compared against Wire B which has just been put up without
being pre-stretched
Now we subject both wires to the same forces over the same period of
time. I would expect that going forward Wire A will not stretch as
far as Wire B, but is more likely to break and break sooner under
significant force than Wire B because it has already been
pre-stretched. Wouldn’t this be correct?
If this is not correct, can you please explain why?
Tnx & 73
Bob KQ2M
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