Topband: 1/2^ tower addendum

[K9AY]

> Is it practical to shunt feed a 1/2^ vertical?  ON4UN's book doesn't
address feeding this monster, at least not that I could find.  Obviously,
it is grounded by the footings.

> Ron - WA9IRV

----

>From my past experience with AM bradcast arrays, 1/2 wave towers are a real
mess for conventional feeding, whether series-fed or shunt-fed.

The best solution I have seen is to make the tall tower a "ground plane" or
"vertical dipole" by attaching either radials 1/4 wave down from the top and
angled outward, or skirt wires 1/4 wave up from the bottom, running down
parallel to the tower. Both methods provide an effective counterpoise for
the portion above, which is shunt fed above the elevated counterpoise. Both
methods would benefit from additional radials at ground level, but will
probably function well with a modest radial system. These radials will also
improve the lightning protection of the tower.

73, Gary
K9AY