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Installing new
200-foot Rohn 45G Tower
Rohn 65G
Rotating Tower
page
Lightning
Station Grounds and
grounding
Contesting and
Boatanchor Room
Antenna System and
my house station
In an effort to
upgrade towers I
needed to replace a
195-foot Rohn 25G
with a Rohn 45G
tower. Rather
than totally
disassemble the
25G tower section-by-section
and install the 45G
section-by-section, we used the
following method……
The 25G coming
down from 195 feet
to 110 feet for the
crane lift.
Removing erection
fixture prior to attaching the
sling to the Rohn
25G.
This Rohn 25G
floats on an single
insulator, and was
195 feet high. It
supported my 160
meter four square
and served as an
omni directional
antenna. The Rohn
25G was stripped
section-by-section
to 110 feet. In this
picture Justin
Storey climbs down
after attaching the
cloth crane sling to
the tower at the 75
foot level. A new
Rohn 45G is waiting
to be lifted.
WW4LL Fred acts
as a spotter
directing the lowering
effort
as W8JI Tom and
Justin walk the
tower base out away
from the insulator
as the Rohn 25G
tower is lowered.
The Rohn 25G is
at 45 degrees. There
is hardly any bend
or flex in the
tower, it comes down
smoothly in one 110
foot piece.
This is the
worse-case bending
point for the 25G,
since it is almost
horizontal. Notice
there is almost no
sag in the tower.
Despite being over
20 years old the 25G
didn’t bow or bend
with a single lift
point at 66%
of tower height.
Never lift at a
section joint, lift
in the middle of a
section and attach
a soft sling around the whole
tower while wrapping
around one leg to
avoid sling
slippage.
The new 140 foot
tall 45G ready to
lift. Because the
fully extended crane
jib was too close to
load limit, we
removed two
sections. This made
the actual lift
length120 feet.
Guylines are
attached to the
tower while on the
ground.
As the 45G goes
up, the tractor
moves the base
towards the
insulator. The tower
went up smoothly.
Notice the base
is held off the
ground. Guylines at
35, 70, and 105 feet
are dangling from
the tower. You can
see the 20 feet of
45 we removed laying
to the left. This
would have lifted
fine, but the boom
extension required
would have put the
jib too close to the
limit. Instead we
picked the tower at
the 75 foot level.
Again this was at
about 2/3 of the
full height in the
middle of a section.
The tower is now
nearly vertical and
the base is getting
close to the
insulator. The
insulator is a
single pin point
that floats. If all
three legs are
attached solidly to
three insulators, it
creates huge
stresses on the
insulators. For this
reason I always use
a single floating
pin insulator. To
restore torsional
stability, guys at
70 and 140 feet are
star bracket guyed.
This will allow
stacking of 20
through 10 meter
Europe yagis on the
tower. The
tower will become
the run tower for
20-10 meters while
still working as an
insulated base
series-fed tower on
160 meters.
This new 200-foot
tower will also
support 160 meter
four square elements
(each 1/4 wave long)
and long ropes that
attach to ends of 80
and 160 meter
dipoles on the
300-foot tower in
the background and a
rotating tower.
Antennas are in the
clear and well away
from other antennas.
The 300-foot tower
is 500 feet away.
This system is
carefully planned to
avoid interaction or
having antennas
beaming through
obstructions.
The copper pipe
forms spark-gaps for
lightning
protection. The base
is home-made from a
standard Rohn pier
plate. The
rectangular steel
tubing is welded to
a vertical 1-inch
diameter solid steel
rod that is machined
to fit the insulator
pin. The rod floats
on the insulator top
pin to prevent
insulator twisting
or rocking stress.
Radials and copper ring are brazed to copper pipes.
After installation, radials and ring were covered with landscaping cloth and
driveway stone.
Copper pipes are bent in or out to set spark gap distance.
The 140-foot
level star guying
bracket is lifted
into place. The
105-foot guy bracket
is visible at the
photo bottom.
The 45G at 170
feet. Waiting the
final sections and
upper two sets of
guy lines.
The erection
fixture is moved up
into position to
lift more tower. The
175- foot guy
bracket is visible
near the top.
The new tower,
still incomplete and
not at full height,
but after a good
day’s work.
Below…the full
tower completed
after two weekends.
Top two layers of
guys are 3/8 inch
fiberglass rod.
Bottom layers all
1/4 inch EHS.
Two of the legs
are aligned so the
Yagis can be bolted
directly to the flat
face using crossover
plates. This
simplifies aiming
fixed beam antennas
at Europe.
Part of an
ongoing upgrade with
the
New Contest Room
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