Dear Gang,
It is interesting to hear all of the comments about the "Inverted U"
antenna. It appears that I was not totally clear about my antenna...
Mine is strung between two very tall trees. I used a slingshot to shoot
nylon monofilament fishing line over the tops of the trees, and 3/32"
black cord to support the antenna at each end.
At the feed end I have a Tupperware(rectangular) box that houses the
inductor and the vacuum variable. The feed end is nearest the house. It
is fed at ground level through the 3" B&W coil stock. The tap is set for
minimum SWR. A Jennings UCLS-1000 (1000 pfd) vacuum variable is tapped
to the coil at a point of minimum SWR and fed against ground.
Of course the vacuum variable is tuned for minimum SWR.
At the feed end I have FOUR (4) 8 foot ground rods from Home Depot. A
piece of #4 copper wire was wrapped around each ground rod and soldered
with a propane torch (it does require substantial heat). To this "ground
bus" is soldered twelve 130 foot radials.
The antenna goes up 60-70 feet, 100 feet approximately from the SE to
the NW, and then down to another ground bus composed of FOUR (4) 8 foot
ground rod and #4 wire. There are twelve 130 foot radials at this end
(the far end) also. The far end of the antena is terminated at the
GROUND BUS. I also tied this far end to the ground radial system of a
"4XRay-array" (after 4X4NJ) sloping vertical I have up for 160.
The antenna works very well. I just need to hear better. For hearing I
have an 80 meter beverage to the North, a full-size 160 meter "flat-top"
dipole up about 6-10 feet, a EWE to Europe with a K2ZJ preamplifier, and
a EWE to the SW with an inside ICE preamplifier.
73,
John, W4NU
Atlanta
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