MCQs in Antennas Part I

This is the Multiples Choice Questions Part 1 of the Series in Antennas as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

Online Questions and Answers Topic Outline

• MCQs in Basic considerations
• MCQs in Wire Radiators in Space
• MCQs in Isotropic Radiator
• MCQs in Current and Voltage Distributions
• MCQs in Resonant and Non-resonant Antennas
• MCQs in Antenna Terms and Definition
• MCQs in Antenna Gain and Resistance
• MCQs in Bandwidth, Beamwidth and Polarization
• MCQs in Grounded and Ungrounded Antennas
• MCQs in Grounding Systems and Matching Systems
• MCQs in Antenna Types
• MCQs in Directional and Non-directional Antennas
• MCQs in Microwave Antennas
• MCQs in Wideband and Special Purpose Antennas

MCQs in Antennas Series

Following is the list of multiple choice questions in this brand new series:

Antennas MCQs

PART 1: MCQs from Number 1 – 50                        Answer key: PART I

PART 2: MCQs from Number 51 – 100                   Answer key: PART II

PART 3: MCQs from Number 101 – 150                 Answer key: PART III

PART 4: MCQs from Number 151 – 200                 Answer key: PART IV

PART 5: MCQs from Number 201 – 250                 Answer key: PART V

PART 6: MCQs from Number 251 – 300                 Answer key: PART VI

PART 7: MCQs from Number 301 – 350                 Answer key: PART VII

PART 8: MCQs from Number 351 – 400                 Answer key: PART VIII

PART 9: MCQs from Number 401 – 450                 Answer key: PART IX

PART 10: MCQs from Number 451 – 500                 Answer key: PART X

SEE: More Questions and Answers in Antennas

Start Practice Exam Test Questions Part I of the Series

1. What is the polarization of a discone antenna?

• A. Vertical
• B. Horizontal
• C. Circular
• D. Spiral

2. If the antenna increases 3.3 times how much does the radiated power increase?

• A. 3.3 times
• B. 10.89 times
• C. 9.9 times
• D. 6.6 times

3. When speaking of antennas. ______ is a section which would be a complete antenna by itself.

• A. image
• B. top loading
• C. bay
• D. quarterwave

4. In what range of frequencies are most omnidirectional horizontally polarized antennas used?

• A. VHF, UHF
• B. VLF, LF
• C. SH, EHF
• D. MF, HF

5. If the current ratios of the two or more elements must be held 5% and the phase angle to 3° the antenna is called a

• A. end fire array
• B. critical phased array
• C. broadband array
• D. wideband array

6. A device that converts high frequency current into electromagnetic wave.

• A. Antenna
• B. Loudspeaker
• C. Microphone
• D. Transducer

7. Which is a non-resonant antenna?

• A. Rhombic antenna
• B. Folded dipole
• C. End-fire array
• D. Yagi-Uda antenna

8. Gain of a half-wave dipole antenna over isotropic.

• A. 2.15 dB
• B. 1.76 dB
• C. 1 dB
• D. 0dB

9. Very low signal strength in antenna.

• A. Minor lobes
• B. Null
• C. Antenna patterns
• D. Major lobes

10. What is the gain of the Hertzian dipole over isotropic antenna?

• A. 1.64 dB
• B. 2.15 dB
• C. 1.76 dB
• D. 1.55 dB

11. ______ is the measurement of a unilateral antenna properties of directivity

• A. Phase angle
• B. Antenna gain
• C. Beamwidth
• D. Bandwidth

12. In testing transmitter to prevent interfering with other stations, which type of antenna must be used?

• A. Void antenna
• B. Dummy antenna
• C. Hertzian antenna
• D. Isotropic antenna

13. The best solution to fading is _____.

• A. space diversity
• B. frequency diversity
• C. polarization diversity
• D. wavelength diversity

14. _____ is the amount of uncertainty in a system of symbols

• A. Bandwidth
• B. Enthalpy
• C. Entropy
• D. Quantum

15. If an antenna has a gain of 3 dB, it increases the output of the transmitter by

• A. 10,000 times
• B. 1000 times
• C. 100 times
• D. 1 million times

16. Top loading is used in an antenna in order to increase its ______.

• A. practical height
• B. beamwidth
• C. effective height
• D. input capacitance

17. A horizontal antenna is _____.

• A. vertically polarized
• B. horizontally polarized
• C. centrally polarized
• D. circularly polarized

18. All elements in a beam _____ antennas are in line

• A. collinear
• B. yagi
• C. broadside array
• D. log-periodic

19. Which does not use vertical polarization antenna?

• A. AM Broadcasting
• B. FM Broadcasting
• C. Mobile Communications
• D. Satellite Communications

20. 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

21. _____ is an antenna with a number of half-wave antenna on it.

• A. Antenna array
• B. Tower
• C. Omni-directional
• D. Rhombic

22. 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

23. An antenna with very high gain and very narrow beamwidth.

• A. Helical antenna
• B. Discone antenna
• C. Horn antenna
• D. Parabolic dish antenna

24. 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

25. _____ is the horizontal pointing angle of an antenna

• A. Azimuth
• B. Angle of elevation
• C. Right angle
• D. Beamwidth

26. 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

27. 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

28. Discone radiation pattern is ______.

• A. omnidirectional/vertical polarized
• B. unidirectional
• C. bidirectional
• D. figure of eight

29. _____ is an open-ended slot antenna

• A. Helical antenna
• B. Rhombic antenna
• C. Notch antenna
• D. Cassegrain antenna

30. Which antenna is a properly terminated?

• A. Marconi
• B. Rhombic
• C. Dipole
• D. Yagi-Uda

31. What is the radiation characteristic of a dipole antenna?

• A. Omnidirectional
• B. Bidirectional
• C. Unidirectional
• D. Hemispherical

32. What is the theoretical gain of a Hertzian dipole?

• A. 1.76 dB
• B. 2.15 dB
• C. 3 dB
• D. 0 dB

33. An antenna with unity gain

• A. Rhombic
• B. Half-wave dipole
• C. Isotropic
• D. Whip

34. How will you increase the gain of an antenna?

• A. By adding several antennas in parallel
• B. By focusing the radiated energy in one desired direction
• C. By making antenna rods thicker
• D. By making the antenna size larger

35. An antenna which is one-tenth wavelength long

• A. Hertzian dipole
• B. Loop antenna
• C. Marconi antenna
• D. Elementary doublet

36. What is the minimum number of turns a helix antenna must have?

• A. 3
• B. 5
• C. 4
• D. 6

37. What is the gain of isotropic antenna?

• A. 10
• B. 1
• C. 10
• D. 100

38. Which of the following improves antenna directivity?

• A. Driven element
• B. Reflector element
• C. Director element
• D. Parasitic element

39. The antenna radiates _____ polarized waves when the transmitter antenna is horizontally installed.

• A. Vertically
• B. negatively
• C. horizontally
• D. circularly

40. The length of a Marconi antenna to operate with 985 kHz is ______.

• A. 200 ft
• B. 500 ft
• C. 250 ft
• D. 999 ft

41. What is the front-to-back ratio of an antenna which radiates 500 watts in a northernly direction and 50 watts in a southernly direction?

• A. 25000 dB
• B. 10 dB
• C. 100 dB
• D. 20 dB

42. If 4 kW in antenna produces 50 μV/m in a receiving antenna, a 15 kW will produce _____.

• A. 200 μV/m
• B. 10 μV/m
• C. 100 μV/m
• D. 20 μV/m

43. If the radiated power increase 10.89 times, the antenna current increases by ______.

• A. 3.3 times
• B. 6.6 times
• C. 1.82 times
• D. 10.89 times

44. The frequency of operation of a dipole antenna cut to a length of 3.4 m.

• A. 88 MHz
• B. 44 MHz
• C. 22 MHz
• D. 11 MHz

45. Comparing the signal strength arriving at the driven element from the desired direction to the signal strength reaching the driver from the opposite direction.

• A. Directivity
• B. Sensitivity
• C. Beamwidth
• D. Front-to-back ratio

46. What is the capture area of a dipole operated at 75 MHz?

• A. 4 mm
• B. 2 m²
• C. 2.088 m²
• D. 4.088 m²

47. _____ of an antenna is a measure of how the antenna concentrates its radiated power in a given direction.

• A. Efficiency
• B. Power
• C. Gain
• D. Polarization

48. Shortening effect of an antenna that makes it appear as if it were 5% longer.

• A. End effect
• B. Flywheel effect
• C. Skin effect
• D. Capture effect

49. Harmonic suppressor connected to an antenna.

• A. Low-pass filter
• B. High-pass filter
• C. M-derived filter
• D. Constant-K

50. A simple half-wavelength antenna radiates the strongest signal

• A. at 45 degrees to its axis
• B. parallel to its axis
• C. at right angles to its axis
• D. at 60 degrees to its axis

Complete List of MCQs in Communications Engineering per topic

Series of Multiple Choice Questions in Electronics Systems and Technologies

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