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 _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
