The following question was in a private email from Dave, W4JVN, but the
answer is probably of interest to many on the reflector.
>Guys, What's a good source for free wire to make all these radials??
>I need some.
>Dave W4JVN
>
Dave, I'm an electrician. When we rewire a building, the old wire is
scrapped. Further quantities of wire come from the odd lengths left at the
end of a spool. Great source, but unfortunately hard to tap unless you are
an electrician. In our union local, there are many ham electricians. If
you know any, ask them if they could save up some scrap wire for you.
Failing that, check with any metal recyclers who might be located nearby.
The scrap from building rewires etc is sold to recyclers at a price lower
than pure copper because to the recycler removing the insulation is an
added cost. They used to just burn it off, but nowadays they aren't
permitted to do that. Even if you have to pay the price of copper, it's
still by the pound and still cheap.
The next best source I'm aware of is electric fence wire, available at farm
suppliers such as Tractor Service Co or Quality Farm and Fleet. It costs
about $25.00 for a half mile. I've never used it. I think it's galvanized,
so should stand burial OK. Aluminum will not. It will be attacked and
destroyed by chemical reactions in the soil.
There is another reason to avoid aluminum. It's the reason electricians
are not fond of it. That is, when aluminum is in a compression connection
such as a screw terminal and it cools, the aluminum is squeezed. The
squeezing causes it to spread sideways. When it warms up, it doesn't
expand as much as it was squeezed because it's now wider. Sort of like
expecting toothpaste to be resilient. The result is that the copper
terminal expands more than the aluminum, so the joint becomes loose. If
any appreciable current is flowing through the joint, it will then become
hot. If hot enough, the aluminum will begin to oxidize. Aluminum oxide is
a pretty good insulator. You get the picture. I'm using aluminum wire for
my elevated radials, but I make sure that I periodically check the screws
in the connections for tightness. There are also joint compounds available
from electrical suppliers which will help.
There may be others who can suggest other sources of wire. If so, let's
hear from you.
73,
Larry, N9DX
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