[TowerTalk] 2 pier pins

[Phil Camera]

There is no such thing as a "2 pier pin" base.  The Rohn flat plate for use with a pier pin installation is to be used with a single pier pin.  These plates are not to be bolted down.  I think you do not understand the meaning of pier pin.

The pier pin is a single, unthreaded pin (about 3/4" dia.) which is set into the top of the concrete tower base.  The flat pier pin base in merely set on top of the pin and is free to rotate.

Even though this flat plate design is not the best (a tapered base is best since it allows the tower to "lean" over as the guys stretch slightly in high winds), it is better than encasing a tower section in the concrete base.  With the pier pin design, as your tower twists due to high winds, mainly acting on the antenna and that torque being transmitted down the tower and trying to "twist" the tower at the base, the pier pin allows the tower to move and transmits those torsional forces into the guys instead, which can resist that force.

Hope this helps.  Rohn does make a bolt down base design but it is different than the pier pin flat plate.  Phil  KB9CRY