At 08:06 PM 12/22/2001 -0500, Tom Rauch wrote:
>I'm still trying to decide what to do for an 80-meter vertical antenna
>also, so I also would appreciate seeing a discussion of options for
>70 foot verticals.
================================
Forrest Gehrke, K2BT, wrote a comprehensive, 6 part series on Vertical
Phased Arrays. The final article, part 6, carried his tested
recommendations for construction of 80 M elements. This article was
published in Ham Radio, May, 1984.
The tubing sizes started at 1 1/2" OD X .125 wall down to 1/2" X .049 wall.
His article also included additional materials required to complete the job.
At today's prices, the elements would be quite expensive. One might wish to
use the ideas shown in ON4UN, using irrigation tubing.
I am using a much modified Hytower, with the 2" tubing extended further
than the original design. I had to use some top loading since I could only
get to 58 ft with tubing at hand, so I made a small top hat. It plays very
well with 60 radials. I suspect anything above about 44 ft with top loading
will work very well over a ground system of 60 radials minimum.
The old Hytower construction method would not be hard to duplicate if one
had access to some of the Rohn BX style tower sections, some heavy wall
fiberglass tubing for insulation and aluminum tubing of 2" OD down to about
1" OD.
INK N4OO
AN Wireless Self Supporting Towers are now available! Windloading tables,
foundation diagrams and charts, along with full details are now at the
AN Wireless Web site: http://www.ANWireless.com
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