Topband: Rohn 25 Vertical questions.

[Rob Atkinson]

The proper way to use a tower like yours as a base excited monopole is
to construct a pier of concrete with a bottom plate pin bowl that is
steel and bonded to copper strap that goes down on each of four sides
of the pier to the ground ring.  The reason for this is so that there
is no voltage gradient across the concrete.  You need to obtain a Rohn
25 bottom tapered section and a porcelain Lapp or Austin insulator
that has a bottom cap and pin that seats in the bowl.  Now your tower
is correctly insulated in a single point so it can rotate under wind
stresses.  The insulator should have all of the voltage across it in
the event of a lightning strike, and you need to have a ball gap
between the tower and the grounded steel pin receptacle on the top of
the pier.   Your tower should be guyed according to Rohn
specifications, but the guys if steel, must be broken up with johnny
ball insulators.

If I were planning such an antenna I'd opt for a free standing tower,
skirt fed with insulated standoffs holding vertical wires, one off
from each face, and tied together with horizontal rings about every 25
feet of height.

73
Rob
K5UJ