Question 31C4

The ability to manually point the antenna and acquire a signal is key to diagnosing this problem. 1. **Faulty antenna control module (B):** The control module is the "brain" of the antenna system. It's responsible for calculating satellite positions, driving the motors to the correct azimuth and elevation, interpreting position feedback (from encoders, not gyros for typical ground stations), and executing the initialization sequence. If the antenna moves but fails to initialize and can be pointed manually, it strongly suggests the motors and RF chain (antenna, coax, LNB, IF amp) are functional. The issue lies in the module's logic, its ability to interpret position sensors during initialization, or its command execution for the automatic sequence. It might be commanding movement but failing to confirm its "home" or initial position correctly. 2. **Defective coax cable (A) or Bad I.F. amplifier (C):** If either of these were faulty, you would not be able to acquire a signal at all, even when manually pointing the antenna. Since signal acquisition is possible, these are incorrect. 3. **Bad Gyro repeater motor (D):** This term is somewhat ambiguous in this context for a fixed ground station. Satellite antennas use azimuth and elevation motors. While a motor *could* be bad, the fact that the antenna "goes past" the AZ/EL and can be manually pointed successfully indicates the motors themselves are functioning. The problem isn't the mechanical movement, but the *control* of that movement during the initialization phase.