SBCA Network Design 5

Question 1

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

Accepted Answer

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

Answer

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

Question 2

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

Accepted Answer

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

Answer

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.

Question 3

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

Accepted Answer

Off-axis satellite antenna gain reduction

Answer

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.

Question 4

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

Accepted Answer

To encrypt content and control subscriber authorization to decrypt it

Answer

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.

Question 5

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

Accepted Answer

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

Answer

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.

(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test

(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test

SBCA Network Design 5