In a message dated 99-07-09 14:36:06 EDT, K0HB@ARRL.ORG writes:
> My tentative plan is a bit more devious. The current tower sits on
> 6 (three sets of two) channel-iron stubs (from old telephone
> central office equipment rack) buried 4 feet into the concrete.
>
> I have a 5/8" thick carbon-steel plate which I'm considering attaching
> (probably weld) to those stubs. In this plate I would drill
> a bolt pattern to match the bottom of the Wilson and insert four 1"
> by 8" bolts pointing up, spot weld the bolt heads in place, excavate
> a bit around the existing base, and bury the whole mess in another
> half-yard of concrete (about 6" deep on top and the rest around the
> outside of the existing block).
>
> Maybe I should just dig a new hole!
>
I didn't get your original post so maybe you could let me know what
the existing base size is and what size you need for the Wilson.
I take it you're trying to use an existing base for a new tower -
that's a good idea. A new hole is the best idea but with good engineering you
can adapt the existing one. Instead of welding the new plate to the existing
stubs, I'd rather see the stubs cut right at the top of the concrete. Then
you can drill new holes in the concrete and use epoxy to install new anchor
bolts. You can rent a concrete drill at your local rental yard. Then the
plate will be sitting on or near the top of the concrete with no tricky
welding required.
If you're going to expand the anchor, you'll need to attach the existing
concrete to the new stuff. Use your rented concrete drill to drill some hole
that you'll epoxy rebar into the new pour.
Cheers, Steve K7LXC
Champion Radio Products
Tower Tech
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