>I, too, noticed there is no numbers given for the dimension "D" which is the
>depth of the anchor. I did notice, however, that the diagrams show the top
>of the anchor rod just protruding from the ground which suggests to me you
>should bury it as deep as possible. Mine are down about 6 feet. I used 9
>foot anchor rods so I could have about a foot of rod above ground.
My old Rohn book shows the DEPTH "D" in the first column of the chart
(drawing C620643) and the block number is the depth in feet, ie "4d" anchor
is 4 ft down, the "6b" anchor is 6 ft down, etc.
By taking the "4b" anchor from 4ft deep to 6ft deep you have made it a
"6a" anchor, raising its holding power from 7,800 pounds to 12,600 pounds.
A >50% improvement for 50% deeper hole--but that is a cheap >50% since
the only thing that changed (other than the required rod length) is the
depth of excavating. The quantity of concrete and rebar remains the same.
73 John W0UN
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