A word about using Rohn's flat plate mounts.
Several years ago I helped the XYL of an SK dispose of her OM's ham
equipment. One of the last things sold was his 60 feet of Rohn 25
tower. It was attached to the concrete slab which was like 4x4x6 by one
of Rohn's flat plates and bolts at each corner.
She didn't want the mounting plate left, but would be ok with the slab,
so we used a sledge to knock off the thoroughly corroded bolts and once
we removed the mounting plate we saw that it had nearly corroded through
on the bottom side to the top, although from the top the corrosion
wasn't visible. Apparently the slab wasn't flat or crested to allow
water to flow away from the plate. It pooled underneath and the years
of water being present had corroded the plate to the point where within
a few months it might have failed and the whole 60 ft guyed tower had
come down when the base slipped.
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