At a former QTH, I had a 113-ft shunt-fed tower, with a couple of yagis for
top loading. I had over 200 slightly-buried radials, filling a rectangle
approximately 270-ft by 140 ft, with the tower in the center.
I had a short (185-ft) European Beverage that crossed within 50 feet of the
tower, 10-ft. high. I had a 600-ft. East and West wire (unidirectional,
switched at
each end) that ran over the edge of the radial field, about 70 feet from the
tower.
There was never any noticable noise pickup from the tower on the East and
West Beverage. This as compared with three Beverages I had 1/2 mile away in
the woods.
The short European Beverage near the tower, however, had some interesting
coupling
to the tower. It wasn't by design, but it just happened to work out that the
feedline (75 ohm hardline) was about 1/2 wave electrical length. When I
switched the antenna switch so the vertical was in-line (hooked to the amp pi-
net), signals on the short Beverage always INCREASED in strength. I assume
this was because signals being picked up on the vertical were being
coupled
to the Beverage. In times of local storm activity, however, the NOISE coupled
from the tower to the short Beverage was stronger than the enhanced signals,
and I would copy signals better with the tower switched out-of-line. (At all
times cited I was receiving on the short Beverage, not the tower itself. I
seldom found signals better on the tower than on the short Beverage near it).
Signals were better copy on the 500-ft Beverage 1/2 mile out in the woods
about 80 percent of the time.
73/Jon AA1K
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REPLY FROM: Zaimes, Jon
Having read all messages which started with KZ5MM's noisy Beverage, it
appears that the proximity (noise) problem (Beverage near Tx vertical)
exists when the Tx vertical has elevated radials. Conversely, a Beverage
seems to co-exist okay with a nearby vertical which uses non-elevated
radials.
The N4KG feed method is interesting. I notice that if you remove all but
one of the radials, it looks suspiciously like a half-sloper :-)
73, de Earl, K6SE
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