Dear Steve K9SL:
Assuming that you wish the installation to be performed with reasonable
(or larger) safety factors, you need the services of a professional engineer
licensed in your state who has experience with towers and tower foundations.
He or she will need engineering data from the manufacturer of the tower and
from the possible suppliers of the new bottom section. He or she will need
to know if there are exceptional facts about your site. They include wind
experience, soil type, and expected antenna loads.

"Real world experience with" your tower, I submit, is of little value to
the goal of having the tower installed with reasonable safety factors.
Almost anything for a tower "bottom" will "work" for a while.

In lieu of professional assistance, the advice of Mr. Ferrell is of
value.

It sounds as if you do not need to use anywhere near the safety factor I
used in a recent tower installation that is in a populated area that is not
too far from a several story building. The building can cause extra wind
pressure. The top many feet of soil was just fill. Severe damage and risk
to life could result from a failure. The resulting foundation removed all
of the soil down to a hard-pan, built up the base a little with manufactured
and well compacted soil, and then used enough reinforced concrete to
counter-balance the tower even if there had been no soil on the sides of the
foundation. I do not use such extreme measures with towers out in the
country and well away from houses or people. However, my experience is that
the wind loads under those circumstances are significantly above those
specified by building codes. The building codes seem not to assume open
spaces.

Good luck. Mac (and a P.E.) N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home:
"steve" wrote in message
oups.com...
Any more suggestions? I amlooking for folks with real world experience
with this tower. Thanks
Steve K9SL