Furuno FAR-2157-D - Manual (Page 10)

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Assembling the antenna unit
The antenna unit should be assembled before mounting it. Follow the procedure below to
assemble the antenna unit. The numbers in parentheses refer to the parts numbers shown in the
illustration on the next page.
1. Grease the O-ring(1) and set it to the O-ring groove in the flange on the rotation coupler on the
antenna base. Fasten the feeder waveguide to the antenna base with hex bolts B(2). Coat the
surface of the waveguide flange with silicon rubber, referring to the illustration below for instruc-
tions.
2. Loosely fasten the antenna radiator to the antenna base with hex bolts(3) and(6), flat
washers(5) and (7), spring washers(4) and (8) and hex nut(9).
3. Grease the O-ring(1) for the antenna radiator and set it to the O-ring groove on the feeder
waveguide flange on the antenna radiator. Fasten the feeder waveguide to the antenna radiator
with hex head bolts(2).
4. Fasten the waveguide clamp(13) to the waveguide clamp insulator(14) with hex head bolt(10),
flat washer(12) and spring washer(11).
5. Securely fasten the antenna radiator to the antenna base.
How to coat waveguide flange with silicon rubber
How to coat waveguide flange with silicon rubber
Choke guide
O-ring
O-ring
Silicon
rubber
Silicon rubber
(1) Do not let sealant contact O-ring groove.
(2) Evenly coat flange with silicon rubber at the locations shown
below.
Use enough silicon rubber so that it oozes out when
fastening bolts. Wipe off surplus. Be sure silicon rubber
does not contact choke guide or feeder waveguide.
Note: The surface to be coated with silicon rubber should be
cleaned beforehand to remove foreign material or silicon
rubber previously applied.