I have been using small guage wire for radials for many years with excellent
results in the Pacific Northwest. My first 80 meter 4 square had several miles
of number 21 motor rewinding insulated (polyester/polyamideimide) wire around
it. I am told this is normal high temperature motor rewinding wire from Essex.
I found the easiest way for me to deal with connecting the small wires was to
lay an 18 inch square piece of copper clad circuit board at the base of the
antenna. I use common 60/40 solder for radial attachment to the circuit board.
I purchase 10 pound spools of this wire from a motor winding shop and fit them
on a home-made radial plow pulled by my riding lawn mower. My latest 90 foot
top loaded 160 TX vertical has 64 of these small guage (#21) radials extending
an average of 90 feet around it. I have made numerous attempts to measure the
resistance of the radial field during installation that have always ended up
with my conclusion the value is small enough that I
cant measure it reliably. Adding the last 20 radials to the 160 antenna
caused no measurable change in the 25 ohm driving impedance. A pound of Number
21 wire produces over 400 feet of radials. My radial plow is adjustable for
depth of 2 inches or 4 inches. I laid the radials around the160 vertical at 4
inches deep and then installed a 40 meter 4 square around the 160 vertical with
radials at 2 inches deep. The 40 meter radial field of 240 radials when
interconnected to the 160 radial field showed no perceptable change in 160
meter antenna driving impedance. I can see no measurable electrical performance
issues related to wire diameter. When I changed QTH 3 years ago I pulled up a
few of the 80 meter 4 square radials that had been in the ground for ten years
plus and the insulation and wires were as bright and shiny as the day I put
them in the ground. YMMV . You can count on one hand the number of times I have
broken a wire while installing these hundreds of radials. I hav
e concluded that for my purposes smaller guage wire is just fine. Lightning
protection may be a whole other issue however. Oh and yes I got country number
100 in 2 years time on 160 this morning when I worked Ross 9M2AX shortly after
working N8S. Lee K7TJR Oregon
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