Practice Test Geeks(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test
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Network Design 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.

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  1. What is the function of a 'guard band' in satellite frequency plan design?

    Answer: A reserved frequency buffer between adjacent carriers to reduce inter-carrier interference

    Guard bands are unused frequency gaps placed between adjacent carriers to reduce spectral spillover and prevent adjacent channel interference in the transponder.

  2. When designing a satellite network for a geographically dispersed enterprise, what is the primary disadvantage of GEO satellite links for latency-sensitive applications?

    Answer: The approximately 240ms one-way propagation delay causes issues for real-time protocols

    The approximately 35,786 km altitude of GEO satellites results in roughly 240ms one-way (480ms round-trip) propagation delay, which disrupts latency-sensitive protocols like VoIP and interactive gaming.

  3. Which parameter in a satellite link budget accounts for losses due to imperfect antenna illumination and edge-of-coverage beam rolloff?

    Answer: Off-axis satellite antenna gain reduction

    Off-axis or edge-of-coverage gain reduction accounts for the lower satellite antenna gain experienced by earth stations located away from the center of the satellite's coverage beam.

  4. In a satellite broadcasting network, what is the role of a conditional access system (CAS)?

    Answer: To encrypt content and control subscriber authorization to decrypt it

    CAS encrypts broadcast content using entitlement control messages (ECMs) and entitlement management messages (EMMs) to ensure only authorized, paying subscribers can decrypt and view the content.

  5. What is the primary reason satellite network designers specify a 'clear-sky' link margin in their link budgets?

    Answer: To provide a reserve of signal strength to overcome rain fade and other impairments

    Clear-sky margin is the excess signal strength above minimum threshold under ideal conditions, providing the reserve needed to maintain the link during rain fade, atmospheric absorption, and other degradation events.

  6. A network designer is evaluating whether to use single-channel-per-carrier (SCPC) or multi-channel-per-carrier (MCPC) for a point-to-point trunk link. When is SCPC preferred?

    Answer: When traffic is continuous and high-volume between two fixed points

    SCPC is preferred for dedicated high-volume point-to-point trunks where continuous full-time capacity is needed, offering simple operation without the need for multiplexing equipment.

  7. In a satellite network employing spread spectrum techniques, what is the primary advantage of CDMA over FDMA for the return link?

    Answer: CDMA allows all terminals to transmit simultaneously on the same frequency using unique codes

    CDMA assigns unique spreading codes to each terminal, allowing simultaneous transmission on the same frequency band without frequency planning, though all terminals contribute to aggregate interference.