SBCA System Maintenance 3

Question 1

What is the purpose of a waveguide pressure window in a satellite uplink system?

Accepted Answer

To maintain pressurized dry air inside the waveguide and prevent moisture entry

Answer

Waveguide pressure windows seal the waveguide system to keep it pressurized with dry nitrogen or air, preventing moisture from causing arcing or signal degradation.

Question 2

Which parameter is checked to verify that a high-power amplifier (HPA) is operating within its linear region?

Accepted Answer

Output back-off (OBO) relative to the saturated power rating

Answer

Output back-off measures how far below saturation the HPA is operating; maintaining adequate OBO ensures linear, interference-free amplification.

Question 3

During a scheduled maintenance window, a technician discovers that the BUC (Block Up-Converter) output power is 3 dB below spec. What should be checked first?

Accepted Answer

DC power supply voltage and current draw of the BUC

Answer

A 3 dB power drop often indicates a power supply issue, so verifying DC voltage and current is the first diagnostic step before replacing the BUC.

Question 4

What maintenance task is critical when replacing a feedhorn on a prime-focus dish?

Accepted Answer

Re-peaking the antenna for maximum signal after feedhorn installation

Answer

After replacing a feedhorn, the antenna must be re-peaked to ensure the new feedhorn is correctly positioned at the focal point for maximum gain.

Question 5

A satellite dish's actuator motor moves the dish but the position sensor reports no change. What component has most likely failed?

Accepted Answer

The position sensor (reed switch or encoder)

Answer

If the motor operates but position feedback is absent, the position sensor (reed switch or optical encoder) that tracks dish movement has failed.

(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test

(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test

SBCA System Maintenance 3