Andrew operation and maintenance Specifications download pdf (Page 54)

Chapter 3 - Operation

42S315F 3-2

3.2.3 Signal Peaking Procedure

With the RF components functioning, perform the signal peaking procedure

as follows: (The initial setting of the elevation angle should be very nearly

correct, having been set to a horizontal reference.)

1. Jog the antenna in azimuth until the satellite signal is peaked.

2. Loosen and calibrate the azimuth angle indicator by adjusting and

fixing the pointer at the known azimuth angle of the satellite. Tighten

the screws holding the pointer and the indicator plate.

3. If fine adjustment of the elevation angle is required, jog the antenna

slightly in the elevation axis to peak on the satellite signal.

4. If required, loosen and calibrate the elevation indicator by adjusting

and fixing the pointer at the known elevation angle of the satellite.

Tighten the pointer screw.

5. Peak the feed polarization on the signal as follows:

a. Rotate feed until the signal peaks.

b. Monitor receiver C/N meter or a power meter.

c. Rotate the feed counterclockwise until the signal decreases by

1 dB. Record the signal level. Mark a line on the feed

mounting plate and a matching line on the hub.

d. Rotate the feed clockwise until the meter has passed through

the peak and has decreased to the level recorded in Step c.

Make a mark on the hub in line with the mark of the feed

mounting plate.

e. Measure the distance between the marks on the hub.

Calculate the mid-point between these marks. Rotate the feed

until the mark on the feed mounting plate is aligned with the

mid-point.

6. With the antenna peaked on a satellite signal, monitor the receiver

C/N meter or a power meter. Loosen the nuts which lock the studs

and adjust the subreflector spacing for maximum received signal. Use

a scale to verify that the three subreflector adjustment studs are

equally spaced from the support clamps. This will verify that the

subreflector is not skewed and consequently steering the antenna

beam away from the feed. After the maximum received signal is

obtained, torque all 3/4-inch hardware to 6 ft-lb. If further

adjustment of the subreflector is required, refer to Subreflector

Adjustment procedure later in this section.

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Andrew operation and maintenance Specifications Page 54