K5NA wrote recently about his experience with a 40m wire beam. We've
used a 7 element 40m wire beam for Field Day (N6AW 3A) for several years
and had great success with it.
The design was taken out of an old Ham Radio article (I can dig up the
reference if anyone is interested). All the elements were log-driven
using open wire line (the brown plastic stuff with cut-outs) and fed
through a tuner. Since FD was set up at a softball diamond equipped
with night lighting, we stretched a 5/8" trucker rope from the left
field light pole to the third base light pole and used this as a support
for the antenna "boom". This pointed the beam at W3 (from So Cal). The
elements were tied off to stakes in the grass (vampire lawyers?) using
twine, inverted Vee fashion. The boom was at 60 ft, and the ends were
about 25 ft off the ground. We got some BIG dudes to pull on the boom
rope so there was only about 3 ft sag over the 225 ft run.
How did it work? Pretty good, even for 100 W. We used it on 40 SSB
(our toughest band/mode here) and averaged ~800 Qs for the years we used
it (including a couple of 1st place 3A finishes). The LP direct feed
system is appealing bcause all the elements are getting "juice", even at
this low height. I would be interesting to see what a model of this
configuration would predict.
73, Kevin N6ER (ex NC6U)
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