System Troubleshooting & Maintenance Flashcards
7 cards from real SBCA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 System Troubleshooting & Maintenance flashcards as text
A technician measures an LNB output and finds the signal is 6 dB weaker than expected. If the cable runs are within spec, what is the most likely remaining cause?
Answer: LNB noise figure degradation or internal gain reduction due to component aging
A 6 dB drop with cables in spec and proper alignment most likely indicates LNB internal component degradation reducing conversion gain.
When troubleshooting a satellite system using a spectrum analyzer, what does a signal with symmetrical sidebands spaced at equal intervals from the carrier indicate?
Answer: Intermodulation distortion products from amplifier nonlinearity
Symmetrical intermodulation products (IMD) at equal spacing are characteristic of nonlinear amplifier distortion, often caused by an overdriven amplifier stage.
What is the correct procedure when a DiSEqC 1.0 switch stops responding to commands from the IRD?
Answer: Verify 13/18V switching voltage is present at the switch input, check cable continuity, then test with a known-good IRD
DiSEqC faults are often caused by insufficient voltage at the switch or cable issues, so systematic verification starting with power and continuity is the correct first step.
A broadcast facility notices periodic audio/video dropouts occurring every 24 hours at exactly the same time. What is the most likely cause?
Answer: A scheduled automated process or equipment cycle causing interference
Perfectly periodic dropouts at fixed times are characteristic of a scheduled process such as a backup, reboot cycle, or automated maintenance task causing interference.
What does an excessively high noise temperature (Tsys) in a satellite receive system indicate?
Answer: Additional noise sources are degrading receiver sensitivity beyond design specifications
High Tsys means the system is adding more thermal noise than designed, reducing sensitivity and degrading C/N ratio on received signals.
During preventive maintenance on a satellite uplink facility, which safety precaution is MOST critical before working on the HPA (High Power Amplifier)?
Answer: Lockout/tagout the HPA power supply and confirm RF output is at zero before physical access
HPAs produce dangerous RF radiation and high voltages; lockout/tagout and confirming zero RF output are mandatory safety steps before physical access.
A receive-only satellite system works perfectly in clear weather but suffers complete signal loss (not just degradation) during heavy rain. What is the most likely explanation beyond simple rain fade?
Answer: The dish is undersized creating a very small rain fade margin, causing complete signal loss
When rain causes complete outage rather than gradual degradation, it indicates the link margin is so small that moderate rain exceeds available fade margin.