Furuno FAR-2157 Assembling the antenna unit, How to coat waveguide flange with silicon rubber

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

(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.

Silicon

O-ring rubber

Choke guide

O-ring

Silicon rubber

Note: The surface to be coated with silicon rubber should be cleaned beforehand to remove foreign material or silicon rubber previously applied.

How to coat waveguide flange with silicon rubber

1-2