TM 11-5985-335-15
a.
Unload the wooden box and the cartons containing the AS-1425/GRC near the mast.
b.
Attach the antenna backmount to the antenna reflector with the pins provided in the reflector assembly
as illustrated in figure 2-3.
c. Using two people, lift the antenna reflector assembly and slide it onto the mast cap as shown in figure 2-4, and
make sure that the index marks on the two units match.
d.
Tighten the crosshandle bolts on the antenna backmount as illustrated in figure 2-5.
e.
Secure antenna to mast cap by inserting quick release pin through holes in antenna frame and mast cap
until head of pin is against frame tube.
f Insert the feedhorn through the circular opening in the antenna reflector. Turn the feedhorn assembly so that the
index arrow on the feedhorn mounting plate matches the appropriate polarization index arrow on the reflector, as shown
in figure 2-6.
g.
Mount the feedhorn to the reflector with the four wingbolts as shown in figure 2-7. Stow the feedhorn
flange cover plate, using the stowage bolt holes near the flange.
h.
If use of the deicer equipment is anticipated, connect ac power (115 volts, 60 Hz) at the power connector
shown covered in figure 2-7 on the feedhorn assembly.
CAUTION
There is a possibility of antenna failure due to a lack of
proper waterproofing and RF leakage. This is caused by
failure of Neoprene Rubber "O" rings to remain seated
in the grooves of the antenna waveguide joints during
installation. The retention of the "O" rings can be
accomplished by applying silicon adhesive to the rings
prior to assembling the waveguide sections (ADHESIVE
SEALANT, RTV, GENERAL PURPOSE, TYPE I,
CLEAR (NSN 8040-00-833-9563)).
i. Clamp one 4 1/2-foot section of CG-3251/GRC flexible waveguide to the feedhorn (fig. 2-8). A clamp is
provided on the waveguide section. Stow the flexible waveguide cover in the clip provided on the waveguide.
j. Attach the four yellow-coded guy cables and the messenger cable to the eyebolts on the antenna backmount.
Figure 2-9 shows a typical guy cable arrangement for the antenna.
k. Clamp one 15-foot section of CG-3307/GRC flexible waveguide to the 4 1/2-foot section of CG-3251/GRC
flexible waveguide. The clamp is provided on the 15-foot waveguide section.
CAUTION
Make sure that the guy cables are manned when raising
the AS-1425/GRC.
l. Attach waveguide clamps (fig. 2-10) and additional waveguide sections as the mast is being raised.
m.
Complete the waveguide run (and power cable run, if used) to the shelter, using cable hanger assemblies
as required with the messenger cable.
Change 2
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