Maybe I wasn't too clear on the bamboo - wire situation. When I used the wire
vertical
the bamboo pole was used as a support, where the wires first were just taped
to the bamboo. They were three wires for 10, 15 and 20 m, coming from common
feed point, and running the length of the varnished bamboo pole, taped to it
at about 2 foot intervals. They were touching the bamboo with their full
length. I could not resonate them. Try it , you'll see.
The problem here is in the lossy (RF dielectric-wise) bamboo that to me acts
as a capacitively coupled to the wire radiator (it's more like your string of
resistor going partially to the ground). Resonant frequency of the bare and
insulated wire (same gage, same length) is also different.
Quad spreaders contact bamboo in very small area. I always use plexiglass
spacers between the wire and the bamboo/clamp.
With vertically polarized antennas trees have some effect. (I will try to
"gamma match" the tree here while flying baloon vertical, see what I get.)
On the salt water: I had interesting experience while operating as P40A on 80
m this year in WPX SSB and CW. I had an Inverted Vee with porcelain egg
insulator at the end and a braided rope going to the tie point. In the
morning I found my inverted Vee hanging by the tower, rope was snipped about
6 inches from the insulator. Thought must have been defective or something
(this probably happened early in the night, no wonder I could not get pileup
going). The second night I watched the SWR meter, and sure enough, around
midnight, SWR went crazy and inspection revealed, rope broke again. Then I
realized what happened: Salt from the air landed on the rope and when the
moisture level from condensation soaked the rope, it became conductive, and
simply burned off. Ceramic insulator looks like got its share of salt and did
some conducting too.
My point is, and lessons I have learned: I want all my power to get to the
antenna with minimum losses and radiate as much of it as possible. Anything
that contributes to the losses and I can minimized, I will. Otherwise it ads
up geometrically.
It's not the laud ones everyone can work, it's the weak ones others can't
hear that win the contest!
73 de Yuri
oK3BU, VE3BMV
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