Topband: Small gauge wire for radials

[Lee K7TJR]

   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 have 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