ViaSat Series 8345, Installation Manual

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Chapter 3 - Operation
3.3.1 Adjustment Procedure
The following is the focal length adjustment procedure.
1. Subtract the feed measurement M from 62.12, giving difference D.
D=62.12 - M
2. Attach the feed spars to the dish with the slotted brackets. Use only one
screw, in the hole near the end of the spar.
3. Set each spar screw so that it is located a distance D above the mark on
the spar bracket and tighten. Refer to Figure 3-1.
Figure 3-1. Focal Length Inspection and Adjustment
4. Re-measure the feed location, and verify that its new distance L from the
reflector is given by the equation:
L=62.12 + (1.5 x D)
If not, incrementally adjust all spars by equal amounts to obtain measurement L.
5. Re-measure C/N.
42S199F 3-2