Trivia Questions On Antenna Theory And Wave Propagation! Quiz
Questions and Answers
- 1.
Top loading is used in an antenna in order to increase its ______.
- A.
Practical height
- B.
Beamwidth
- C.
Effective height
- D.
Input capacitance
Correct Answer
C. Effective heightExplanation
Top loading is used in an antenna in order to increase its effective height. Top loading refers to the addition of an element or structure at the top of the antenna to extend its height. By increasing the height, the effective height of the antenna is increased, which improves its performance in terms of signal reception and transmission. This is especially important for antennas operating at lower frequencies, where a taller antenna is needed to achieve better coverage and increased gain.Rate this question:
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- 2.
A horizontal antenna is _____.
- A.
Vertically polarized
- B.
Horizontally polarized
- C.
Centrally polarized
- D.
Circularly polarized
Correct Answer
B. Horizontally polarizedExplanation
A horizontal antenna is horizontally polarized because the orientation of the antenna elements is parallel to the ground, resulting in the electromagnetic waves being transmitted or received in a horizontal plane. This polarization is commonly used in applications such as television broadcasting and long-range communication, where the signals need to propagate over long distances with minimal interference.Rate this question:
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- 3.
All elements in a beam _____ antennas are in line
- A.
Collinear
- B.
Yagi
- C.
Broadside array
- D.
Log-periodic
Correct Answer
A. CollinearExplanation
The correct answer is collinear. In a collinear antenna array, all the elements are aligned in a straight line. This configuration allows for a more focused and directional radiation pattern, which is useful for long-distance communication. Yagi, broadside array, and log-periodic antennas have different configurations and radiation patterns, so they are not the correct answers in this case.Rate this question:
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- 4.
Which does not use vertical polarization antenna?
- A.
AM Broadcasting
- B.
FM Broadcasting
- C.
Mobile Communications
- D.
Satellite Communications
Correct Answer
B. FM BroadcastingExplanation
FM broadcasting does not use vertical polarization antenna. FM stands for Frequency Modulation, and it uses horizontal polarization for transmitting signals. Horizontal polarization is preferred in FM broadcasting because it helps minimize signal interference and provides better signal quality.Rate this question:
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- 5.
Lightning rods must be mounted a top structure not less than ___ above the highest point.
- A.
10 cm
- B.
20 cm
- C.
30 cm
- D.
40 cm
Correct Answer
C. 30 cmExplanation
Lightning rods must be mounted at a height of at least 30 cm above the highest point of a structure. This is because lightning rods are designed to attract lightning strikes and provide a path for the electrical discharge to safely reach the ground, thus protecting the structure from damage. By placing the lightning rod at a higher point, it increases the likelihood that it will be the target for lightning strikes, rather than the structure itself.Rate this question:
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- 6.
_____ is an antenna with a number of half-wave antenna on it.
- A.
Antenna array
- B.
Tower
- C.
Omni-directional
- D.
Rhombic
Correct Answer
A. Antenna arrayExplanation
An antenna array is a collection of individual antennas that are arranged in a specific pattern. Each individual antenna in the array is typically a half-wave antenna. The purpose of the array is to enhance the performance of the antenna system, such as by increasing the gain or directing the radiation pattern in a specific direction. Therefore, an antenna array can be described as an antenna with a number of half-wave antennas on it.Rate this question:
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- 7.
Which antenna radiates an omnidirectional pattern in the horizontal plane with vertical polarization?
- A.
Marconi antenna
- B.
Discone antenna
- C.
Horn antenna
- D.
Helical antenna
Correct Answer
A. Marconi antennaExplanation
The Marconi antenna is the correct answer because it radiates an omnidirectional pattern in the horizontal plane with vertical polarization. This means that the antenna emits signals in all directions horizontally, making it suitable for applications where a signal needs to be broadcasted evenly in all directions. The other options, such as the Discone antenna, Horn antenna, and Helical antenna, may have different radiation patterns or polarization orientations, making them unsuitable for this specific requirement.Rate this question:
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- 8.
An antenna with very high gain and very narrow beamwidth
- A.
Helical antenna
- B.
Discone antenna
- C.
Horn antenna
- D.
Parabolic dish antenna
Correct Answer
D. Parabolic dish antennaExplanation
A parabolic dish antenna is the correct answer because it has a very high gain and a very narrow beamwidth. The parabolic shape of the dish allows it to focus radio waves onto a single point, resulting in a highly concentrated signal and increased gain. The narrow beamwidth means that the antenna can transmit and receive signals in a very specific direction, making it ideal for long-range communication and satellite applications.Rate this question:
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- 9.
_____ is the horizontal pointing angle of an antenna
- A.
Azimuth
- B.
Angle of elevation
- C.
Right angle
- D.
Beamwidth
Correct Answer
A. AzimuthExplanation
Azimuth is the horizontal pointing angle of an antenna. It represents the direction in which the antenna is pointed horizontally, measured in degrees clockwise from true north. This angle is crucial in determining the direction in which the antenna is transmitting or receiving signals. The other options, such as angle of elevation, right angle, and beamwidth, do not specifically refer to the horizontal pointing angle of an antenna.Rate this question:
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- 10.
What determines antenna polarization?
- A.
The frequency of the radiated wave
- B.
The direction of the radiated wave
- C.
The direction of the magnetic field vector
- D.
The direction of the electric field vector
Correct Answer
D. The direction of the electric field vectorExplanation
The direction of the electric field vector determines antenna polarization. Antenna polarization refers to the orientation of the electric field in the radiated wave. It can be either vertical or horizontal, depending on the direction of the electric field vector. The orientation of the electric field vector is crucial in determining the efficiency and effectiveness of the antenna in transmitting or receiving signals.Rate this question:
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- 11.
A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW. What is the gain in dB, obtained by the use if the reflector. (Gain referred to this particular dipole).
- A.
4.75
- B.
2.6
- C.
1.81
- D.
4.24
Correct Answer
B. 2.6Explanation
The gain in dB is calculated using the formula: Gain (dB) = 10 * log10 (Pout / Pin), where Pout is the output power and Pin is the input power. In this case, the input power without the reflector is 20 kW and with the reflector is 11 kW. Plugging these values into the formula, we get: Gain (dB) = 10 * log10 (20/11) = 2.6 dB.Rate this question:
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- 12.
What is the estimated medium wind loading in the Philippines for antenna tower design?
- A.
300 kph
- B.
100 kph
- C.
200 kph
- D.
250 kph
Correct Answer
C. 200 kphExplanation
The estimated medium wind loading in the Philippines for antenna tower design is 200 kph. This means that the antenna tower should be designed to withstand wind speeds of up to 200 kilometers per hour. This is an important consideration in the design process to ensure the structural integrity and stability of the tower in high wind conditions.Rate this question:
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- 13.
Discone radiation pattern is ______.
- A.
Omnidirectional/vertical polarized
- B.
Unidirectional
- C.
Bidirectional
- D.
Figure of eight
Correct Answer
A. Omnidirectional/vertical polarizedExplanation
The correct answer is omnidirectional/vertical polarized. A discone antenna is designed to have a radiation pattern that is omnidirectional, meaning it radiates and receives signals equally in all directions. Additionally, the discone antenna is typically vertically polarized, meaning the electric field of the radio waves is oriented vertically. This combination of omnidirectional and vertical polarization makes the discone antenna suitable for applications where a wide coverage area is desired, such as in communication systems or radar systems.Rate this question:
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- 14.
_____ is an open-ended slot antenna
- A.
Helical antenna
- B.
Rhombic antenna
- C.
Notch antenna
- D.
Cassegrain antenna
Correct Answer
C. Notch antennaExplanation
A notch antenna is an open-ended slot antenna that is designed to suppress or reject signals in a specific frequency range. It consists of a narrow slot cut into a conducting surface, which creates a resonant circuit that attenuates signals at the desired frequency. This antenna is commonly used in applications where interference needs to be minimized or eliminated, such as in wireless communication systems or radar systems.Rate this question:
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- 15.
Which antenna is a properly terminated?
- A.
Marconi
- B.
Rhombic
- C.
Dipole
- D.
Yagi-Uda
Correct Answer
B. RhombicExplanation
A properly terminated antenna is one that has a termination impedance that matches the characteristic impedance of the transmission line it is connected to. The Rhombic antenna is known for its ability to be properly terminated, meaning that it can be matched to the transmission line impedance without causing reflections or signal loss. The Marconi, Dipole, and Yagi-Uda antennas may also be properly terminated, but the Rhombic antenna is specifically mentioned as the correct answer.Rate this question:
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