[TowerTalk] Rohn 45 Tower

[Ron Todd]

I am installing 90 to 100 feet of Rohn 45 very soon.
My property is  125 wide and have trees and water lines, and power lines in the way.
I want to go out 80 feet for my guys.
I will be using 10 foot I beams to connect the guys to.  4 foot in cement.
I plan on back guying the I beams also.  
Question,  Do I measure my 80 feet at the I beam or the end of my back guy ?

Ron K4WZ