[TowerTalk] concrete bases for freestanding towers

[WA8JXM]

Many years ago I had a 64' freestanding tower with a 3el triband beam (TA-33) on it.  The base was only 2 cu yards of concrete.  As far as I remember, that was all the manufacturer (Heights) recommended at the time.

Now when I look at anyone's recommendations, the base requirements are much larger.  Rohn (and others) recommends 3 cu yards even for a 40' BX tower.    I had used only 1 cu yard for a freestanding 40' tower.

Is my memory faulty, or have the recommended bases grown over the years?  Were the old recommendations inadequate, or has everyone grown super conservative over the years?   "If one yard is adequate, three will be better, so let's use five yards"???

As one ham commented on the air yesterday, the only failures he has ever heard of were in the tower itself, not the base falling over.  

Ken