When I lived outside Holton, Kansas in the 1980s, I had a pair of 2 wire
beverages, each 2 wavelengths long on 160 meters, situated in an 80 acre field
with the common feed point 1000 feet from the station. They were fed through a
home made two core transformer with CATV RG 59 coax (I got a 1000 foot roll for
$15 from a hardware store going out of business)
A 12VDC, DPDT relay powered through the coax switched them in NE or SE
direction. They worked so well that hams 75 miles distant in Kansas City swore
that I was making up all the stations I could hear and they couldn't. I never
did need a preamplifier. Sometimes the signal on a beverage was actually
louder than on my N-S oriented inverted vee at 110 feet.
On several occasions I was able to replace a European station on the NE antenna
with a Caribbean station on the SE antenna with no QRM between them. Their
orientation was 45 degrees and 135 degrees, magnetic.
Over a period of several months I was able to graph the patterns by comparing
the signal on the beverage to the signal on my vertical, then drawing a line on
a map through my location to the QTH of the station I was receiving and
plotting relative signal strengths on the line. Both of them had very narrow
beamwidths. Unfortunately, over the years and - several overseas moves - I
have lost the data sheets and graphs.
One interesting thing was that I could copy ignition noise from cars going past
on a highway two miles away and tell which way they were travelling by how they
faded out on one antenna and then came in on the other one. I could also
estimate their speed and a lot of them were driving well over the 55MPH limit
in effect at the time.
I had to be careful with the shield of the coax because it would arc over
inside the shack during thunderstorms if I didn't have it grounded out. Once
it started a grass fire and burnt up about 100 feet of the coax where it was
lying on the ground.
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
|