This set of Antennas Multiple Choice Questions & Answers (MCQs) focuses on “Radio Wave Propagation – Ground Wave Propagation”.
1. Ground wave is always __________ polarized.
a) Vertically
b) Horizontally
c) Either vertical or horizontal
d) Neither horizontal nor vertical
View Answer
Explanation: If the wave is horizontally polarized, then the electric field is short circuited by the earth. So the ground wave is always vertically polarized and vertical antennas are used.
2. Ground wave propagation is used for signals up to frequency __________
a) 2MHz
b) 2GHz
c) 30MHz
d) 30GHz
View Answer
Explanation: Ground wave propagation is used for signals up to frequency of 2MHz. Ground waves are vertically polarized and transmitting and receiving antennas are placed closely and the wave follows the curvature of the earth.
3. The broadcast signals received at low frequencies during day-time are due to _________
a) Ground wave
b) Space wave
c) Sky wave
d) Tropospheric waves
View Answer
Explanation: Ground wave propagation is used for signals up to frequency of 2MHz. It is useful for the broadcast and low frequency signals. Space waves are also known as tropospheric waves useful for FM reception. Sky wave propagation is used for long distance communication.
4. Ground wave propagation is also known as _________
a) Surface wave
b) Tropospheric wave
c) Ionospheric wave
d) Stratospheric waves
View Answer
Explanation: Ground waves are also known as Surface waves as the wave propagates close to the surface of earth. Space waves are known as tropospheric waves and Sky waves as Ionospheric waves.
5. The ground wave propagation uses horizontal polarized antennas
a) True
b) False
View Answer
Explanation: If the wave is horizontally polarized, then the electric field is short circuited by the earth. So the ground wave is always vertically polarized and vertical antennas are used.
6. Which of the following is particularly used for VLF?
a) Surface wave
b) Tropospheric wave
c) Ionospheric wave
d) Stratospheric waves
View Answer
Explanation: Ground waves are also known as Surface waves are used for low frequencies and broadcasting. Tropospheric waves are used for Mf and HF signals. Ionospheric waves are used for long distance communications.
7. Ground wave field strength is given by E= _________
a) AEo/d
b) A(Eo)2/d
c) dEo
d) AEo/d2
View Answer
Explanation: The ground wave field strength at a point \(E=\frac{AE_o}{d} V/m \)
Where Eo is field strength of wave at unit distance from transmitting antenna
A is factor of ground losses
D is distance of point from Transmitting antenna.
8. Which of the following propagates by gliding over the surface of earth?
a) Surface wave
b) Tropospheric wave
c) Ionospheric wave
d) Stratospheric waves
View Answer
Explanation: Ground waves are also known as Surface waves. Ground waves are vertically polarized and transmitting and receiving antennas are placed closely and the wave follows the curvature of the earth.
9. How the ground wave losses vary with high frequencies?
a) Increases
b) Decreases
c) Does not depend on frequency
d) Increase or decrease
View Answer
Explanation: Ground wave propagation is used at below 2MHz frequency. Ground wave propagation is used for short distance. By using sufficient power and low frequencies it can be used effectively. Ground wave losses increase rapidly with frequencies.
10. The electric field of the component increases in ground wave when it tilts more at the surface.
a) True
b) False
View Answer
Explanation: As the wave front tilts more and more towards the surface then the electric field gets short circuited. As it gets reduced with tilt, at some point it is completely attenuated.
Sanfoundry Global Education & Learning Series – Antennas.
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