[Towertalk] Mounting fixed antennas

[Jim Idelson]

Hi all,

The big project for the summer here is to remount three monobanders on the side 
of my R25 tower. Right now they are clamped to a singe leg, and they do slip, 
causing some surface damage to the tower legs. Not good. I haven't decided how 
to do it right yet. Two of the antennas will be located just above guy points 
on the tower. I feel comfortable that a well-secured mounting method using two 
tower legs at those points will be a great solution. Any twisting forces on the 
tower will be transferred directly to the guy wires. But, the third yagi will 
be mounted between the other two - not near a guy attachment point. Twisting 
forces will travel through the tower to the guy points above and below. I was 
thinking that a sort of "safety relief" could be implemented by using a 
boom-to-mast attachment that would SLIP before the tower gets damaged. I'd 
rather have to go up the tower and realign the antenna than replace the tower 
after a catastrophic failure. This can be accomplished by a better mounting 
directly to a single leg with a clamp, or by using two pieces of angle stock 
mounted across two tower legs supporting a short mast offset from the tower by 
12-18 inches. Any thoughts on this kind of approach?

73,

Jim Idelson K1IR
email    k1ir@designet.com
web    http://www.designet.com/k1ir