Date: Wed, 07 Feb 2007 21:41:11 -0500
From: Jon Zaimes AA1K <jz73@verizon.net>
Subject: Re: Topband: Beverage antenna questions
Hi Bruce,
After some recent chatter on the reflector about low Beverages, I
decided to experiment with one of mine here. The Beverage was a
single 440-ft long, 10-ft high wire of some old olive-drab military
zip cord, both wires just shorted at each end and maybe at a splice
or two along the way. It was my original JA Beverage -- at 320
degrees -- when we moved here 9 years ago. A couple of years ago I
added a pair of broadside phased Beverages, 935 feet long, spaced 175
feet in the same direction. This pair has always outperformed the
shorter wire -- even though they pass near my towers and can pick up
a bit of noise at times.
So a few weeks ago I replaced the short single wire with some THHN
no. 12 stranded and lowered the height to about 3 feet. I used this
wire because it was bright orange and would be quite visible where it
crosses some of my trails in the woods. It took the identical path as
the wire it replaced, but was just lower to the ground. I now found
much less difference between the shortie and the long phased pair.
The phased pair still has the edge, but nowhere near the hands-down
performance before I lowered the shortie. Lowering the shortie seems
to have been a definite improvement.
I have begun construction of a second element parallel to the
shortie, this one to be staggered 132 feet and spaced 22 feet from
the original. Before I pair it with the other one I plan to run
separate feedlines to these and do some a/b testing of the
same-length wires, with one (the new one) at 10 feet and the other at
3 feet. I don't plan to leave the shortie at 3 feet because of the
physical obstacle it presents to me (and the deer), and after the
test it will likely be returned to 10 feet (or at least something
above head level) for permanent use in the stagger-phased pair.
My only other low-to-the ground Beverage is 1,000 feet long at 162
degrees, 3 feet high. It's usually about the same in receiving
signals but perhaps a bit quieter than an 880-ft. long single wire up
10 feet in the same direction.
Most of my ground rods at each end are typically 1/2-inch or 3/4-inch
copper water pipe, 3 to 5 feet long. A few older ones are galvanized
steel of similar size. Termination resistors are typically 550 ohms,
though they may be a bit higher on the long phased pair. I haven't
bothered to "tune" any of the terminations for best f/b. Water table
is usually very high here, about ankle height, except in dry Augusts
when it's down a couple of feet. Frozen ground in winter make for
much easier antenna work :-).
73/Jon AA1K
Felton, Delaware
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