Andrew operation and maintenance Specifications download pdf (Page 32)

Chapter 2 - Installation

42S315F 2-20

2.4.6.6 Subreflector Alignment

1. Apply a small amount of light grease or oil to the target mirror shaft. Screw the

target mirror into the hole in the apex of the subreflector a few turns. It does not

need to be tightened.

2. Rotate the mirror so that the Crosshairs are aligned with the adjustment directions of

the subreflector mounting frame.

3. Use the right angle lens set of the theodolite to set the theodolite elevation angle to 0°

(vertical) and view the mirror crosshairs. Rotate the theodolite azimuth to orient the

theodolite crosshairs even with the mirror crosshairs.

4. Using the three threaded subreflector adjusting rods, adjust the distance of the

subreflector from the panel mounting ring to match the dimension given in

Figure

2-1

for the appropriate antenna operational frequency band. Make the measurement

the same at the edge of the subreflector near each of the three rods.

5. Focus the theodolite toward infinity until the theodolite telescope barrel becomes

visible in the mirror. Adjust the subreflector tilt using the three threaded

subreflector adjusting rods. The theodolite crosshairs should appear centered in the

end of the theodolite telescope barrel.

6. Reduce the focal distance of the theodolite until the mirror crosshairs are clearly

visible. Adjust the lateral location of the subreflector until the mirror crosshairs and

the theodolite crosshairs coincide.

7. Tighten all the subreflector adjusting fasteners. Verify that all adjustments have been

maintained.

8. Remove the mirror from the subreflector.

9. Apply duct tape to the lower nuts on the three threaded subreflector adjusting rods

to maintain the tilt and focal length setting; then remove the upper nuts from the

threaded rods. Lower and remove the subreflector from the mounting frame and set

it aside until the reflector has been lifted onto the mount.

2.4.7 Mount Installation

The antenna foundation must be structurally adequate and provide suitable

anchor bolts located and installed per foundation plan. Refer to Site

Preparation manual, #42S314, for site preparation and foundation details for

the appropriate mount [Model 8009A (120°), Model 8009AE (120°) or Model

8009AE (180°)].

WARNING

All personnel atop the mount must use safety belts and have

all ladders properly and safely secured.

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Andrew operation and maintenance Specifications Page 32