Hi all!
I ve been using a 4-sq array with elevated radials for three years now. It s a
very simple design all made by wires in the trees. The radiators are "almost"
vertical and I have 3 elevated radials at each radiator, elevated abt 4 mtrs
above ground. I m using hybrid-
coupler for -90 degrees and a halfwave section of coax for -180. At first I had
a toroid transformer for
-180, but I found that the phasedelay were closer to
160 than 180 deg. The transformer also affected the
hybrid coupler so that it was not possible to get a perfect -90 delay! F/B
improved quite a bit after the
mod.
Talking about efficiency, I mean that there are two
kinds. RADIATION-efficiency and REFLECTION-
efficiency. To benefit from both I guess that there
is no substitute for 100 radials, elevated or
on the ground.
Still, as I ve no room for 100 radials I use elevated
radials so that I at least can get good RADIATION
efficiency, and I must say that so far it s the best
antenna I ve had for 80!
73 s de Lars / SM3BDZ
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|