TM 11-5840-360-14-1-1
2.11.1.2 Rotary Joint Waveguide Positioning. - The
2.11.4 Mounting Instructions
waveguide section on the S-band antenna pedestal
When installing the antenna pedestal and
rotary joint which mates with the RF coaxial cable or
antenna, the antenna and pedestal should be assembled
waveguide run from the receiver transmitter can be
on deck, per paragraph 2.11.1.1, then hoisted into
installed in three different positions (see Figure 2-16).
position and mounted on the mast as a unit. The
The position should be selected to facilitate the most
antenna pedestal is provided with three eye-bolts to
direct transmission line run between the receiver
facilitate hoisting. Nylon web straps (1-1/2-inch wide)
transmitter and pedestal. The pedestal is shipped with
with spring closed hooks should be used to attach and
the waveguide section installed; if it is necessary to
lift the unit.
change the position of the waveguide section, the
When hoisting the pedestal and array, a
following procedure should be used.
spreader bar must be used to prevent the lifting straps
from rubbing against the array face.
NOTE
CAUTION
The following procedure should be
EXERCISE EXTREME CARE TO
performed
before
the
antenna
PREVENT
DAMAGE
TO
THE
pedestal is mounted on the mast.
ANTENNA ARRAY, PARTICULARLY
CAUTION
THE ARRAY FACE PROTECTIVE
EXERCISE EXTREME CARE TO
COVER, WHEN LIFTING.
PREVENT
DAMAGE
TO
THE
Hoist the antenna pedestal (and the antenna
ROTARY
JOINT
ASSEMBLY
array) as follows:
THROUGHOUT PERFORMANCE OF
NOTE
THE FOLLOWING PROCEDURE
The position of the rotary joint
1. Remove all stuffing tubes from the bottom of
waveguide
section
should
be
the pedestal.
checked before the antenna pedestal
2. Remove the coax-to-waveguide transition from
is mounted on the mast; refer to
the rotary joint.
paragraph 2.11.1.2 if it is necessary
3. Turn the rotary joint to one of its three mounting
to change the position.
positions (see Figure 2-16) which will facilitate the most
1. Remove two 6-32 screws from drain holes in
direct transmission line run from the pedestal to the
bottom of array.
receiver transmitter.
2. Rotate the antenna so that the array faces aft
4. Reconnect the coax-to-waveguide transition to
(toward the single eye-bolt); maintain the antenna in this
the rotary joint.
position while hoisting.
5. Install stuffing tubes removed in step 1.
3. Attach three lifting straps to the pedestal eye
2.11.2 Service Platform
bolts and to the shackles on the bottom of the spreader
A service platform is required where the
bar.
antenna is mounted at greater than stand-up working
4. Attach hoisting line to spreader bar and apply
height from the deck or mounting surface. Figures 2-5
sufficient lift to tense straps; insure aft strap is well clear
and 2-6 include (for reference only) details of the
of antenna face.
servicing platform. The guard rail and support gussets
are necessary components of the servicing platform.
5. Carefully hoist unit into position above
2.11.3 Mounting Hardware
preinstalled mounting plate; align mounting holes in
When installing the antenna, the following
pedestal with those on mounting plate and carefully
general rules must be observed as applicable:
lower unit.
1. Corrosion-resistant (i.e.
stainless steel)
6. Shim pedestal supports to assure sound
mounting hardware should be used.
mechanical interface between mounting plate and
pedestal.
2. Mating surfaces of the steel mounting plate and
the aluminum antenna casting should be coated with a
7. Secure pedestal to mounting plate using
silicone compound such as Dow Corning DC4 (Part
stainless steel 3/4-inch bolts, lockwashers, flatwashers
Number 230-1014P3) to prevent dissimilar metal action.
and nuts (four each) before lifting straps are removed.
3. Where guy wires are required, they must be
interrupted by strain type insulators to minimize their
effect on communications equipment.
2-59
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