ANTENNA ALIGNMENT PROCEDURE
Alignment with the satellite is obtained by setting polar- ization, elevation and azimuth. Charts 1, 2 & 3 are to determine the values for your earth station antenna site. “∆L” is the difference between the earth station antenna site longitude and the satellite longitude. Use “∆L” and your earth station latitude to obtain polarization, elevation or azimuth setting.
POLARIZATION OF FEED
Loosen feed horn M6 clamp bolts (12) and turn feed clockwise or counterclockwise, depending on being east or west of the satellite as shown on Chart 1. Align marks on the horn clamp and appropriate mark on the horn scale clamp is installed with arrow pointed toward antenna as shown in Fig. 3.0. Keep cable groove on header in the down position when adjusting polarization. NOTE:
Single Polarity Feed is factory assembled for vertical polarity. If horizontal polarity is desired, rotate feed 90˚ (clockwise or counterclockwise).
ELEVATION
FEED
ASSEMBLY
ARROW
12
ALIGNMENT | +40 |
MARK
FIG. 3.0 - POLARIZATION OF THE FEED
POLARIZATION CHART
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L" IS THE DIFFERENCE BETWEEN THE EARTH STATION ANTENNA SITE LONGITUDE AND THE SATELLITE LONGITUDE
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| NORTHERN | SOUTHERN |
90 |
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| POLARIZATION CHART SIGN VALUES (+ OR | HEMISPHERE | HEMISPHERE | |
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| ANTENNA SITE WEST OF SATELLITE LONGITUDE | - | + | ||
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| ANTENNA SITE EAST OF SATELLITE LONGITUDE | + | - | |
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80 | ANTENNA |
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70 |
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+ | – |
| FEED |
60 |
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To obtain elevation value for your satellite, refer to chart
2.Loosen bolts in curved slots of AZ/EL Housing ¹⁄₈ to ¹⁄₄ a turn (Ref. Fig. 3.1). Turn elevation adjustment bolt clockwise to decrease elevation and counterclockwise to increase elevation. Align the edge of clamp with appropriate mark at the desired elevation reading (Ref. Fig. 3.1). NOTE: Degree values shown on eleva- tion scale are Beam; that is when the antenna face is vertical mechanical elevation is 0˚, while the Beam Elevation (signal) is 22.6˚. This will be an approximate setting. Optimum setting achieved when fine tuning. Temporarily tighten elevation bracket nuts.
AZIMUTH
Align this edge with desired elevation setting (shown at 22.5˚)
20˚ | 10 |
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30˚ | 30˚ |
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40˚ | 40˚ |
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| 50˚ |
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| 70 |
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| 80 | ˚ |
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| 90 | |
ELEVATION ADJUSTING BOLT
POINTER
PIVOT BOLT
AZ/EL
HOUSING
CLAMP
BOLT
ILLUSTRATION) |
| Feed Rotation (Facing Antenna) | |
| For + Polarization, Rotate CCW (Counter Clockwise) | ||
50 | For - Polarization, Rotate CW (Clockwise) | ||
– (SEE |
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| 75° | ||
+ OR |
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40 | 60° | ||
POLARIZATION | |||
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| 40° | ||
30 | 30° | ||
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Use Chart 3 and determine your azimuth setting. Values in chart must be adjusted for magnetic deviation for your location for correct compass reading. Rotate the antenna and mount, pointing it to the correct compass reading for your location and satellite (Ref. Fig. 3.2). Slowly sweep the antenna in azimuth until a signal is found. If the desired signal is not found, increase or decrease elevation setting and repeat the azimuth sweep.
FINE TUNING
Use a signal strength measuring device for final adjust- ments to obtain maximum antenna performance. Alternate between elevation and azimuth fine tuning to reach maximum signal strength until no improvement can be detected. Tighten all hardware. Torque for M8 round head, square neck bolts is 15
FIG. 3.1 - SETTING ANTENNA ELEVATION
AZIMUTH |
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| 20° |
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| 15° |
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20 |
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| 10° |
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| 5° |
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10 |
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0 |
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0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 |
EARTH STATION LATITUDE IN DEGREES NORTH OR SOUTH OF EQUATOR
6 | FIG. 3.2 - ROTATING ANTENNA FOR AZIMUTH | CHART 1 | 7 |
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