POLARIZATION CHART
ANTENNA ALIGNMENT PROCEDURE
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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 |
Alignment with the satellite is obtained by setting polariza- tion, elevation and azimuth. Charts 1, 2 & 3 are to determine these values for your earth station antenna site. “ΔL” is the difference between the earth station antenna site longitude and the satellite longitude. Use “ΔL” and your earth station latitude to obtain polarization, elevation or azimuth setting.
POLARIZATION OF THE FEED
Loosen Feed Horn Clamp Bolts and turn Feed clockwise or counterclockwise, depending on being east or west of the satellite as shown on Chart 1. For course setting, align marks on the Horn Scale (Ref. Fig. 3.0). Polarization chart assumes antenna system polarization is Tx vertical and satellite vertical Pol is perpendicular to plane of geostation- ary arc. For horizontal Tx of antenna, Feed must be rotated
HORN SCALE
CLAMP BOLT |
| ALIGNMENT MARK |
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FIG. 3.0 - Polarization of the Feed
| 70 |
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| + | — | |
ILLUSTRATION) |
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| FEED | |
60 |
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| Feed Rotation (Facing Antenna) | |||
| For + Polarization, Rotate CCW (Counter Clockwise) | |||
50 | For - Polarization, Rotate CW (Clockwise) | |||
— (SEE | ||||
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| 75O |
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OR |
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90˚ from values shown. (Starting point for polarization adjustment is 0˚, as shown in Figure 3.0.) Use a signal strength measuring device for final polarization setting and tighten horn clamp bolts to 4
ELEVATION
Use Chart 2 and determine your elevation setting. Loosen Elevation Pivot Bolts and Bolts in curved slots (both sides) of AZ/EL housing approximately 1 complete turn (Ref. Fig. 3.1). Turn Elevation Adjustment Bolt clockwise to decrease elevation and counterclockwise to increase elevation. Align the edge of the Clamp with appropriate mark on housing at the desired elevation reading. This will be an approximate setting. Optimum setting achieved when fine tuning.
EDGE OF CLAMP
BRACKET
EXAMPLE:
18" ELEVATION
ELEVATION ADJUSTING
SCREW
CURVED SLOT BOLT
ELEVATION
PIVOT
BOLT
CLAMP BOLT
(4 PLCS)
+ | 40 |
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| 60O |
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POLARIZATION |
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| 40O |
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30 |
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| 30O |
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| 20O |
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| 15O |
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| 20 |
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| 10O |
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| 5O |
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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
CHART 1
9
NOTE: Degree values shown on Elevation Scale are Beam; there is no need to compensate for any offset angle. (See Appendix A, Outline Drawing).If clinometer is used, you must compensate for offset angle.
AZIMUTH
Use Chart 3 and determine your azimuth setting. Values in chart must be adjusted for magnetic deviation for your loca- tion for correct compass reading. Rotate Reflector and Mount pointing it to the correct compass reading. Slowly sweep the antenna in azimuth until signal is found. If the desired signal is not found, increase or decrease elevation setting and repeat the azimuth sweep (Ref. Fig. 3.2). Tighten Half Clamp Bolts .
FINE TUNING
Use Signal Tuning Device for final adjustments to obtain maximum antenna performance. Alternate between eleva- tion and azimuth fine tuning to reach maximum signal strength, until no improvement can be detected. Certain models utilize the optional azimuth fine tune feature (refer to Figure 3.2). This allows the azimuth to be fine tuned by loos- ening the (4) Carriage Head Bolts and Swivel Nut which allows adjusting the Azimuth Fine Tune Adjusting Bolt for the peak signal. When fine tuning is complete, tighten and torque all AZ/EL hardware to 12
IMPORTANT: Recheck and repeat torque on four Clamp Bolts, Fig. 3.1 in alternating sequence, until all Bolts are equally torqued to 18
FIG. 3.1 - Setting the Elevation
AZIMUTH FINE TUNE
ADJUSTING BOLT
HEX NUT,
CARRIAGE BOLT (4)
HEX NUT,
AZIMUTH
SWIVEL NUT
FIG. 3.2 - Rotating Antenna for Azimuth
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