Hi Earl,
Elevated radials with a base fed tower (albiet insulated base) at ground
level was described by Al Christman in March 1993 QST on page 72. He shows
the 45 degree angle etc. and gives other interesting information. I see no
reason why this can't be done with a shunt fed Gamma match on a grounded
tower although there may be some degradation in performance due to the
tower being grounded.
I have just started to experiment with feeding a 100 foot Rohn 25 grounded
tower with insulated guys. It uses a 36 foot 1" diameter tube Gamma rod
about 30 inches from one leg of the tower. There are presently 4 elevated
resonant radials (not fully installed but 15 foot elevation a target).
However, I referenced everything up at the 5 foot above ground level where
the lower end of the Gamma rod ends and the Omega match is placed as well
as the attachment of the resonant radials. Hopefully this will work better
as the tower ground will be further away and the feedlines from other
antennas exiting on the same tower. I doubt that I will put up many more
unsightly elevated radials but I will probably add several ground mounted
ones at a later date. Hope this gives some more ideas to the discussion.
>I've always considered "elevated radials" to be radials which are
>completely above ground and horizontal, and that the antenna feedpoint is
>also elevated to the same height as the radials.
>
>Discussing this with another ham tonight, I discovered that at least one
>ham who is using "elevated radials" on his shunt-fed tower on 160m
>attaches his 4 radials at ground level, then slopes them upward at a
>45-degree angle to 8 feet high, with the remainder of the radials
>horizontal at 8 feet. Is this the type of "elevated radials" being
>discussed?
>
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