Practice Test Geeks(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test
← All SBCA Flashcard Decks

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

  1. A satellite technician notices that a dish's signal peaks at an azimuth 3 degrees off from the calculated value. What is the most likely reason?

    Answer: Local magnetic declination was not applied when using a compass for alignment

    Magnetic compasses show magnetic north, which differs from true north by the local declination angle; ignoring this offset causes azimuth pointing errors.

  2. What is the function of a waveguide pressurization system in a satellite uplink antenna system?

    Answer: To prevent moisture ingress and maintain consistent dielectric properties inside the waveguide

    Pressurization with dry nitrogen or dehumidified air prevents condensation inside waveguides, which would cause arcing, corrosion, and signal attenuation.

  3. When a satellite modem reports 'ACM mode: no coding found,' what does this indicate in a DVB-S2X adaptive link?

    Answer: The uplink controller cannot find a valid modulation and coding scheme for current link quality

    ACM (Adaptive Coding and Modulation) requires a valid coding scheme selection; 'no coding found' means link conditions are below the minimum threshold for any available MODCOD.

  4. A headend technician observes that signal quality on C-band drops every evening between 6-8 PM but not on Ku-band systems. What is the most plausible cause?

    Answer: Terrestrial microwave interference from C-band frequency reuse links increasing at peak traffic hours

    C-band (3.7-4.2 GHz) shares spectrum with terrestrial microwave links that may experience higher traffic and interference during business peak hours.

  5. After replacing a faulty LNB, a technician confirms signal strength returns to normal but BER remains high. What should be investigated next?

    Answer: The LNB connector or cable between LNB and IRD may have damage causing phase noise or signal distortion

    Good signal strength with poor BER after an LNB swap often points to connector or cable issues that degrade signal quality without significantly reducing amplitude.

  6. What is the primary purpose of monitoring a satellite transponder's power spectral density (PSD) at a receive site?

    Answer: To detect interference, carrier power imbalances, and unauthorized transmissions within the transponder

    PSD monitoring allows operators to identify unexpected carriers, interference sources, and anomalies that would degrade legitimate services sharing the transponder.

  7. A VSAT hub operator receives reports that multiple remote sites lost connectivity simultaneously at the same time. What should be checked FIRST?

    Answer: Hub-side common equipment: HPA, modem, network routing, and uplink signal integrity

    Simultaneous failure at multiple remotes points to a common shared component — the hub-side equipment is the single point of failure that should be investigated first.