Satellite Communications Flashcards
7 cards from real Telecommunications practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Satellite Communications flashcards as text
What is a 'link budget' in satellite communications?
Answer: A calculation of all signal gains and losses along a satellite communication path
A link budget accounts for all gains (antenna gain, amplifier power) and losses (free-space path loss, atmospheric attenuation) to determine whether a satellite link has sufficient signal-to-noise margin.
EIRP (Effective Isotropic Radiated Power) is calculated as the product of:
Answer: Transmitter power and antenna gain
EIRP = Transmitter Power × Antenna Gain, and it represents the equivalent power an isotropic antenna would need to radiate to achieve the same signal strength in the direction of the beam.
Which technique transmits two independent signals on the same frequency using orthogonal signal polarizations (e.g., horizontal and vertical) to double satellite capacity?
Answer: Polarization frequency reuse
Polarization frequency reuse exploits the fact that orthogonally polarized signals do not interfere with each other, allowing the same frequency band to carry two separate signals and effectively doubling capacity.
Adjacent Satellite Interference (ASI) in the geostationary arc is caused by:
Answer: Signals from nearby satellites being captured along with the intended satellite's signal
ASI occurs when the antenna beam of a nearby satellite in the geostationary arc overlaps the receive pattern of a ground station, introducing an unwanted signal alongside the intended one.
The G/T ratio used to characterize satellite receiver performance stands for:
Answer: Gain-to-Noise Temperature ratio
G/T (Gain-to-Noise Temperature) is a figure of merit for a satellite earth station receiver; a higher G/T means the station is better at detecting weak signals relative to its own internal noise.
Which satellite was the first commercial geostationary communications satellite, launched in 1965?
Answer: Intelsat I (Early Bird)
Intelsat I, nicknamed Early Bird, launched in April 1965, was the world's first commercial geostationary communications satellite, providing telephone and TV service between North America and Europe.
In satellite communications, a 'spot beam' antenna pattern refers to:
Answer: A focused antenna beam that illuminates a small geographic area with higher power density
A spot beam concentrates the satellite's radiated power onto a small geographic region, delivering higher EIRP and enabling frequency reuse between non-overlapping spot beam areas.