Andrew operation and maintenance Specifications download pdf (Page 57)

Chapter 3 - Operation

42S315F 3-5

level will peak at the antenna focus; however, this change will

not be as sensitive as the change in the null depths. Peak main

beam signal level and minimum first null depths should

coincide for the best subreflector position.

c. As the subreflector is adjusted toward the optimum focal

position, the first sidelobe levels should decrease and remain

symmetrical within 2 dB. The minimum sidelobe level will

occur approximately at the same subreflector position as the

highest signal level and lowest nulls. Should the sidelobes

become asymmetrical (greater than 2 dB), Step 3 above should

be repeated. It is recommended that after each adjustment of

the subreflector, the antenna azimuth and elevation

adjustments be re-peaked to compensate for any beam

steering due to axial misalignment.

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Andrew operation and maintenance Specifications Page 57