[TowerTalk] concrete bases for freestanding towers

[K7LXC at aol.com]

In a message dated 5/13/2011 6:55:21 A.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  My 40 HDBX has closer to 6 yards under it. It's a block 6.5  square, 6 ft
deep. The old Rohn drawings specified a 4' deep hole. I also  have a yard
of gravel in the bottom of the hole to prevent ice  lensing.
 
    What's ice lensing? I couldn't find it in my  dictionary. Tnx.
 
Cheers,
Steve    K7LXC