On Wed,4/15/2015 8:43 AM, donovanf@starpower.net wrote:
Corrosive soils may damage a buried radial system.
I agree that mechanical durability and environmental factors are the
limit on the size and type wire for both radials and antennas.
In my limited experience, the use of insulated wire significantly
reduces corrosion. I've built a lot of wire antennas using THHN
(ordinary house wire). When I've examined wires that have been up for 8
years or so, the only corrosion I've seen is very close to the ends,
while the wire a few inches inside the insulation are clean and brite.
I've since gone to hard drawn copper for my high wire antennas,
primarily to minimize stretch. With 100# or more of tension on them, I
had to lower my 80M dipoles every couple of years to shorten them. For
hard drawn copper, I buy a spool of bare #8 from a big box store, tie
one end to a tree, the other to a trailer hitch, and pull very slowly
until it breaks. This yields hard drawn copper, roughly 15-20% longer,
approximately #9.
73, Jim K9YC
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