What causes spin fading of satellite signals?

What causes spin fading of satellite signals?

• A. Circular polarized noise interference radiated from the sun
• B. Rotation of the satellite and its antennas
• C. Doppler shift of the received signal
• D. Interfering signals within the satellite uplink band

Answer: (B)

Spin fading of satellite signals primarily arises from the rotation of the satellite and its antennas. As a satellite orbits the Earth, it typically spins to maintain thermal stability and to average out its exposure to solar radiation. This rotation can cause variations in the received signal strength at a ground station due to the changing orientation of the satellite’s antenna relative to the receiving station. When the antenna points directly toward the receiver, the signal is strongest, but as the satellite rotates, the signal may partially weaken or fluctuate as the angle of incidence changes. This results in the phenomenon known as spin fading. The characteristics of the satellite's antenna radiation pattern can also contribute to these fluctuations, although the fundamental cause remains linked to the satellite's rotation. Other factors, such as atmospheric conditions or interference from other signals, do not primarily govern spin fading in this context.

Spin fading of satellite signals primarily arises from the rotation of the satellite and its antennas. As a satellite orbits the Earth, it typically spins to maintain thermal stability and to average out its exposure to solar radiation. This rotation can cause variations in the received signal strength at a ground station due to the changing orientation of the satellite’s antenna relative to the receiving station.

When the antenna points directly toward the receiver, the signal is strongest, but as the satellite rotates, the signal may partially weaken or fluctuate as the angle of incidence changes. This results in the phenomenon known as spin fading. The characteristics of the satellite's antenna radiation pattern can also contribute to these fluctuations, although the fundamental cause remains linked to the satellite's rotation. Other factors, such as atmospheric conditions or interference from other signals, do not primarily govern spin fading in this context.