A good source of spreader material is the local big box hardware or the local
feed/farm store. They stock a fiberglass rod on various lengths and diameters
as supports for electric fences. You can cut it to length with a hack saw, just
be sure to seal ends with polyurethane spray paint. While you at it spray the
whole thing and prevent the glass hairs that will develop over the years and
make the rods a glove only situation. (those hairs hurt and are near impossible
to find in flesh.) They also have high voltage clamps fro the rod to hold wire.
Pretty cheap too. With the clamps and rod you can male just about any
separation you need. They have end of run type insulators that are either
ceramic eggs or polyethylene plastic that are great for center insulators or
end insulators for any wire antenna application.
As for wind wrapping, you could extend one of the lowest fiberglass spacers
out to contact the tower and I think it would stop that for a <40 foot
vertical. A simple black tywrap would be sufficient for tower end of the rod.
For on or below ground radials you can see the effect of your new additions
by how the impedance changes as you add the new ones. By adding 4 at a time and
measuring after each addition you can catch the point where the diminishing
returns hits your compromise level. With increased radial system you might have
to adjust radiator length to recenter lowest SWR or highest gain to your
favorite frequency.
As always your mil age may vary.
73
Nick
WB7PEK
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