Hi Friends,
Had an epic tower party today. We put up 100' of Rohn 80/90
using a heavy lift helicopter. The tower is almost 4' across
with two sets of 1/2" guys, and the base sits on a pier pin.
Its heavy stuff, and the supports for the two 3" thrust
bearings and the prop pitch (system from K6NA) I made from
galvanized 3" x 5" x 1/4" angle iron along with the 26' x 3"
4130 mast and guy wires all added a lot of weight. The
sections seemed too heavy to gin pole, and the area is way
too far from pavement for a crane.
The tower and all other main steel was painted with
excellent zinc dust and epoxy paint, which really works well
in this salty environment but must be mixed in small batches
since it goes off pretty quickly in our high humidity. The
tower was wired on the ground, with the rotator wires and
coax (six 9880 runs) in 2" pvc conduit with 12" square pvc
junction boxes top and bottom.
The huey came on time at 8am and it was breathless still,
after two weeks of 30 to 60 mph winds (62 was my high gust
last wednesday, our original scheduled day). It lifted the
tower upright, but took about ten minutes for a breeze
strong enuf to get the bottom off the ground and onto the
pin, and eventually we got the pin in the hole and started
working the top guys (pilot's weight guage topped out at
5200#). Problem, the huey had 20 minutes fuel on board (he
unloaded drums in my field) so he could pick max weight. I'm
on the av. radio with pilot as he counts down, and the three
teams cranking the guy wires with boat trailer winches
mounted on the rear of the I-beam guy anchors seem to be
cranking and cranking and cranking... then we realize the
old preforms from the original installation I'm using as
grips are slipping on the guys. Horror.
The pilot is ready to drop the load, since he can't lift it
off the pier pin, and I beg him for minutes as we scramble
for the new preforms, which are within arms reach, and the
one klein grip. We made it! Got the Huey on the ground by
8:30 with 2 minutes fuel in the tank, and the tower at a
crazy angle. Now its levelled and tensioned and feels solid
as the rock of Gibralter. Exciting project. Luckily I had a
real quick, smart crew to overcome my stupid error. The old
preforms (surplus, came with the tower) were 9/16" even
though all the paperwork said 1/2", and I thought I had once
measured. As uncle Bernie used to say, "next time measure
twice and cut once".
Soon, the antennas.
Aloha,
Jonathan KH6X
Helen KH6T
kalepa@maui.net
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