This is my work in progress, a 31' telescopic aluminum tower that will be
used primarily for local UHF / VHF and experimental work. The tower has
been in the making for nearly a year to date. It seems there is always
something impeding my time and/or ambition on the project. Our long term
design focus was to build a hurricane resistant structure that would
function in the lowered position up to the maximum wind load of any
attached antenna.
Pictured here is the wall mount to telescopic tube clamp. Machined in a
CNC vertical machining center out of a solid block of aluminum, the
complete assembly was designed with hurricane resistance in mind.
The part pictured below fastens to the top of the bottom tube section. It
manages the raising and lowering of the upper tube via nylon rope and
the custom made pulley. The pulley support does double duty by also
providing a clamping mechanism to lock the upper tube in place when
desired. These parts were also CNC machined from solid aluminum plate.
Pictured to the left is the keyway and upper tube spacer. Attached inside
the lower tube to the bottom of the upper tube, this spacer allows the
nylon raising and lowering cord to attach as well as provides a key are
to prevent rotation of the telescopic sections.
The telescopic aluminum tubes were cut to length and fitted with the
machined fixtures. The lower tube required holes longitudinally to
support the fixture key that runs 12 feet inside the tube! The
base fixture plates were machined and drilled for the support bolts to
the base and four 2 foot long 3/4" bolts were purchased to create the
concrete footer base for support. The next task is to dig, pour and set
the base as well as mount the wall bracket, raise the tower and install
lightning protection; connecting to the ground array already in place.
