J. Bradshaw wrote:
> Hello ALL,
> Our local club has a tower that was donated to us. It is a 58 1/2
> foot, three section tower with 21" from leg to leg at the base,
> tapering to abt 15" at the top.
> The tower is made of steel rod throughout, galvanized. Each foot (3)
> and each section bolts together with a four bolt 1/2" thick pad
> centered on the rod.
> What do we do for a footing? I can't even see aligning four bolts in
> the concrete at each foot. The tower has NO markings whatsoever. We
> assume it is free-standing.
> We have a hole, 4'x4'x 6' deep already dug.
> Any thoughts?
> Jim, AC6TK for the Yucaipa Valley Amateur Radiio Club.
1)Conscript addtl club members to help u lift foot of base sec.
approx. a foot and place support underneath legs (jack stands, cinder
be sure twr sec. is braced well laterally so can't slip off above) so
cuss more than necc. while proceed to Step 2.
2)Rip 4x8' sheet of suitable plywood in half (3/8" may be a bit flimsy,
but use what you have on hand or can spare) to give you 4x4' piece.
3)Using this piece as template, center bottom of sec. on it and drill
of appropriate dia. through existing pad holes in leg and thru plywood.
4)Obtain suitable anchor bolts for application. If, as someone has
this is SSV...consult Rohn book for appropriate spec required.
Engineering docs for
my Tristao call out for 1" by 36"length, w/ 6" hook at bottom, but this
is for a tilt-
over base that would no doubt be subjected to higher lateral loads
during that process
than a non-tilting free-standing tower (disclaimer: I are not an
injuneer). You may be
able to get by w/less than this, but use whatever Rohn calls out for the
size and windload
you plan on supporting.
5)Insert anchor bolts thru holes in plywood and place appropriate
combo on threaded end on "top" of template w/ "hook" end of bolt
6)Use this template as top of form to cover existing 4x4x6' hole. If
SSV calls for larger dim. form., center on longer pieces of 2"x to
support and enlarge hole
7)Pour suitable concrete mix (don't forget the re-bar "cage"!) and wait
8)Conscript new (or now rested) club members to help erect tower and
antennas (don't forget
to test rotor before going up tower and determining "North" =:0...)
9) CU in the pileups!
73 es gud DX, Gerald W5BA
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com