Guess I better speak up. I had a short letter in QST Technical
Correspondance Nov '91 that addressed the effect of a tree on an adjacent
vertical. You can reference that. In short, I had (still have, actually) a
pair of verticals hanging in two large oaks. Each is 58' high with a top
loading coil (77uH) then a horizontal wire about 35' long to bring it to
resonance at 1.83MHz. I found that if the top wire was allowed to touch a
large limb (8" dia) the resistive component went up to 75 ohms. As I moved
the top wire away from the limb the resistive component went down. It
leveled off at about 45 ohms when the wire was around 5 or 6 feet from the
limb. During the same time period my friend, K3BZ, had an 80M vertical
suspended in a tall pine and about a foot from the trunk. I'm not sure of
his exact measurements but I think the resistive component went from 57 ohms
down to 40(?) when he moved the base out to about 6 foot from the trunk.
Wanted to follow this up with a research project but business, 160M, golf
and laziness got in the way. . . . . .
Clay, K3IX
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