ANTENNAS 1. What is the polarization of a discone antenna?
A. end fire array B. critical phased array C. broadband array
A. Vertical B. Horizontal C. Circular
D. wideband array 6. A device that converts high frequency current into electromagnetic wave.
D. Spiral 2. If the antenna increases 3.3 times how much does the radiated power increase?
A. Antenna B. Loudspeaker C. Microphone
A. 3.3 times B. 10.89 times
D. Transducer 7. Which is a non-resonant antenna?
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. Rhombic antenna B. Folded dipole C. End-fire array D. Yagi-Uda antenna
A. image B. top loading
8. Gain of a half-wave dipole antenna over isotropic.
C. bay D. quarterwave 4. In what range of frequencies are most omnidirectional horizontally polarized antennas used?
A. 2.15 dB B. 1.76 dB C. 1 dB D. 0dB 9. Very low signal strength in antenna.
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. 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
C. Entropy D. Quantum 15. If an antenna has a gain of 3 dB, it increases the output of the transmitter by
B. 2.15 dB C. 1.76 dB
A. 10,000 times
D. 1.55 dB
B. 1000 times
11. ______ is the measurement of a unilateral antenna properties of directivity
C. 100 times
A. Phase angle
D. 1 million times 16. Top loading is used in an antenna in order to increase its ______.
B. Antenna gain C. Beamwidth
A. practical height
D. Bandwidth
B. beamwidth
12. In testing transmitter to prevent interfering with other stations, which type of antenna must be used?
C. effective height D. input capacitance 17. A horizontal antenna is _____.
A. Void antenna B. Dummy antenna C. Hertzian antenna D. Isotropic antenna 13. The best solution to fading is _____.
A. vertically polarized B. horizontally polarized C. centrally polarized D. circularly polarized 18. All elements in a beam _____ antennas are in line
A. space diversity B. frequency diversity C. polarization diversity D. wavelength diversity 14. _____ is the amount of uncertainty in a system of symbols
A. collinear B. yagi C. broadside array D. log-periodic 19. Which does not use vertical polarization antenna?
A. Bandwidth B. Enthalpy
A. AM Broadcasting
D. Parabolic dish antenna
B. FM Broadcasting
24. What determines antenna polarization?
C. Mobile Communications D. Satellite Communications 20. Lightning rods must be mounted a top structure not less than ___ above the highest point.
A. The frequency of the radiated wave B. The direction of the radiated wave C. The direction of the magnetic field vector
A. 10 cm
D. The direction of the electric field vector
B. 20 cm
25. _____ is the horizontal pointing angle of an antenna
C. 30 cm D. 40 cm 21. _____ is an antenna with a number of half-wave antenna on it.
A. Azimuth B. Angle of elevation C. Right angle
A. Antenna array
D. Beamwidth
B. Tower
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).
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. 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. Helical antenna B. Discone antenna
A. 300 kph
C. Horn antenna
B. 100 kph
C. 200 kph
B. 2.15 dB
D. 250 kph
C. 3 dB
28. Discone radiation pattern is ______.
D. 0 dB 33. An antenna with unity gain
A. omnidirectional/vertical polarized B. unidirectional
A. Rhombic
C. bidirectional
B. Half-wave dipole
D. figure of eight
C. Isotropic
29. _____ is an open-ended slot antenna
D. Whip
A. Helical antenna
34. How will you increase the gain of an antenna?
B. Rhombic antenna C. Notch antenna
A. By adding several antennas in parallel
D. Cassegrain antenna
B. By focusing the radiated energy in one desired direction
30. Which antenna is a properly terminated?
C. By making antenna rods thicker D. By making the antenna size larger
A. Marconi
35. An antenna which is one-tenth wavelength long
B. Rhombic C. Dipole D. Yagi-Uda 31. What is the radiation characteristic of a dipole antenna?
A. Hertzian dipole B. Loop antenna C. Marconi antenna D. Elementary doublet
A. Omnidirectional
36. What is the minimum number of turns a helix antenna must have?
B. Bidirectional C. Unidirectional D. Hemispherical 32. What is the theoretical gain of a Hertzian dipole?
A. 3 B. 5 C. 4 D. 6
A. 1.76 dB
37. What is the gain of isotropic antenna?
B. 10 dB A. 10
C. 100 dB
B. 1
D. 20 dB
C. 10
42. If 4 kW in antenna produces 50 μV/m in a receiving antenna, a 15 kW will produce _____.
D. 100 38. Which of the following improves antenna directivity?
A. 200 μV/m 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.
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 A. Vertically B. negatively C. horizontally D. circularly
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.
40. The length of a Marconi antenna to operate with 985 kHz is ______. A. 88 MHz 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?
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 A. 25000 dB
B. Sensitivity C. Beamwidth
D. Front-to-back ratio
A. at 45 degrees to its axis
46. What is the capture area of a dipole operated at 75 MHz?
B. parallel to its axis C. at right angles to its axis D. at 60 degrees to its axis
A. 4 mm B. 2 m2 C. 2.088 m2
1. Vertical
D. 4.088 m2
2. 10.89 times
47. _____ of an antenna is a measure of how the antenna concentrates its radiated power in a given direction.
3. bay 4. VHF, UHF
A. Efficiency B. Power
5. critical phased array 6. Antenna
C. Gain D. Polarization
7. Rhombic antenna
48. Shortening effect of an antenna that makes it appear as if it were 5% longer.
8. 2.15 dB 9. Null
A. End effect
10. 1.76 dB
B. Flywheel effect C. Skin effect
11. Beamwidth
D. Capture effect
12. Dummy antenna
49. Harmonic suppressor connected to an antenna.
13. space diversity 14. Entropy
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
15. 1000 times 16. effective height 17. horizontally polarized 18. collinear 19. FM Broadcasting
20. 30 cm
42. 100 μV/m
21. Antenna array
43. 3.3 times
22. Marconi antenna
44. 44 MHz
23. Parabolic dish antenna
45. Front-to-back ratio
24. The direction of the electric field vector
46. 2.088 m2 47. Gain
25. Azimuth 48. End effect 26. 2.6 49. Low-pass filter 27. 200 kph 50. at right angles to its axis 28. omnidirectional/vertical polarized 29. Notch antenna 30. Rhombic 31. Bidirectional
51. The current maximum in a Marconi antenna is found at
A. the base of the antenna
32. 1.76 dB
B. the center of the antenna
33. Isotropic
C. some point between the base and the center of the antenna
34. By focusing the radiated energy in one desired direction 35. Elementary doublet
D. the top of the antenna 52. If an antenna is too short for the wavelength being used, the effective length can be increased by adding:
36. 3 A. capacitance in series 37. 1 38. Parasitic element 39. horizontally 40. 250 ft 41. 10 dB
B. inductance in series C. resistance in parallel D. resistance in series 53. Which of the following antennas is used for testing and adjusting a transmitter for proper modulation,
amplifier operation and frequency accuracy?
A. Elementary
D. By connecting an inductor in series with the antenna 57. Which of the following antennas receive signals in the horizontal plane equality well from all directions?
B. Real C. Isotropic D. Dummy 54. The power fed to a two-bay turnstile antenna is 100 watts. If the antenna has a 2 dB power gain, what is the effective radiated power?
A. 317 watts
A. Horizontal Hertz antenna B. Vertical loop antenna C. Vertical Yagi antenna D. A vertical antenna which is a quarterwavelength long 58. If the length of a Hertz dipole is decreased
B. 158 watts C. 200 watts D. 400 watts 55. What is the gain, in dB of a helical antenna with diameter of λ/3, 10 turns at pitch of λ/4, used at 100 MHz?
A. 16 B. 41.1 C. 31.4 D. 1.25 56. How is it possible to lower the resonant frequency of Hertz dipole antenna?
A. By reducing the frequency at the transmitter B. By connecting a capacitor in series with the antenna C. By the connecting a resistor in series with the antenna
A. its resonant frequency will be lowered its distributed inductance will be increased B. its distributed inductance will be decreased C. its resonant frequency will be increased D. its distributed capacitance between the antenna and ground will be increased. 59. A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, what is the antenna current at the feed-point?
A. 4.0 A B. 2.2 A C. 1.25 A D. 2.0 A 60. A one-quarter wavelength shunt-fed vertical Marconi antenna
A. has maximum radiation in a vertical direction
64. What is the effect of adding a capacitor in series with an antenna?
B. must have a horizontal receiving antenna for the best reception
A. The antenna’s resonant frequency will increase
C. must use a receiving antenna for the best reception
B. The antenna’s resonant frequency will decrease
D. must have a vertical receiving antenna for the best reception
C. The antenna will be physically 5% longer than its electrical length
61. A shunt-fed quarter-wavelength Marconi antenna
D. A capacitor is never added in series with an antenna
A. has maximum RF impedance to ground at its feedpoint
65. How does the electric field strength of a standard broadcast station vary with the distance from the antenna?
B. has a current null at its feedpoint C. has a zero DC resistance to ground D. has zero RF resistance to ground 62. The parasitic element of an antenna system will
A. The field strength of a standard broadcast station vary with the distance from the antenna B. The field strength is directly proportional to the distance from the antenna
B. increase its directivity
C. The field strength remains constant regardless of the distance from the antenna
C. give the antenna unidirectional properties
D. The field strength varies inversely as the distance from the antenna
D. both B and C
66. Stacking elements in a transmitting antenna system
A. decrease its directivity
63. If the length of an antenna is changed from 2.5 meters to 2.8 meters, its resonant frequency will
A. increase B. depend on the velocity factor so the resonant frequency can either be increased or decreased
A. increases the field strength at the receiving antenna B. increases the directivity of the transmitter antenna C. decrease the size of the lobe in the radiation pattern
C. will be unchanged
D. both A and B
D. decrease
67. A vertical loop antenna has a
A. ground wave propagation A. unidirectional radiation pattern in the horizontal plane B. unidirectional radiation pattern in the vertical plane C. omnidirectional radiation pattern in the horizontal plane D. a bidirectional radiation pattern in the horizontal plane 68. In order to get maximum radiation to all surrounding points in the horizontal plane, the antenna used is a
B. space wave propagation C. ionosphere scatter propagation D. sky wave propagation 72. What antenna radiates equally in all directions?
A. Vertical antenna B. isotropic antenna C. Horizontal antenna D. Dipole antenna
A. vertical loop
73. Actual height of antenna should be at least
B. vertical quarter-wavelength rod C. array which includes parasitic elements D. a horizontal Hertz dipole 69. What is the electrical wavelength of a 500 MHz signal?
A. one wavelength B. half wavelength C. quarter wavelength D. three-fourth wavelength
A. 60 centimeters
74. Which antenna is not properly terminated?
B. 6 meters C. 0.06 meter D. 60 meters 70. If the antenna current is doubled, the field strength at a particular position is
A. Resonant B. Non-resonant C. Isotropic D. Whip
A. doubled B. halved
75. ______ is an antenna array which is highly directional at right angles to the plane of the array?
C. multiplied by a factor of four D. divided by a factor of four
A. Broadside array
71. The rhombic antenna is primarily used for
B. End-fire array C. Turnstile array D. Log-periodic array
76. The directivity pattern of an isotropic radiator is
A. a figure-8 B. a sphere
B. Three-quarters of the way from the feed point toward the end C. One-half of the way from the feed point toward the end D. At the feed point
D. a parabola
81. A theoretical reference antenna that provides a comparison for antenna measurements.
77. An isotropic radiator is
A. Marconi antenna
C. a unidirectional cardioid
B. Isotropic radiator A. in the northern hemisphere
C. Yagi-Uda array
B. an antenna high enough in the air
D. Whip antenna
C. an antenna whose directive pattern is substantially incredible
82. A Hertz antenna is operating on a frequency of 2182 kHz and consists of a horizontal wire that is hanged between two towers. What is the frequency of its third harmonic?
D. a hypothetical, omnidirectional antenna 78. The purpose of stacking elements on an antenna.
A. 727 kHz A. Sharper directional pattern B. increased gain C. Improved bandpass D. All of these 79. The advantage of using top loading in a shortened HF vertical antenna is
B. 6546 kHz C. 436 kHz D. 6.546 kHz 83. In horizontal-dipole antenna, the polarization is
A. in the vertical direction A. lower quality factor B. greater structural strength C. higher losses D. improved radiation efficiency 80. Where are the voltage nodes in a halfwave antenna?
B. in the horizontal direction C. circular D. measured at the center of the antenna 84. Increasing the electrical length of an antenna means
A. add an inductor in parallel A. At the ends
B. add a capacitor in series
D. coil
C. add an inductor series
89. What is the gain of an antenna over a half-wavelength dipole when it has 6 dB gain over an isotropic radiator?
D. add a resistor is series 85. Stacking antennas at various angles results in
A. 6.0 dB A. a more omnidirectional reception B. a more unidirectional reception C. a more omnidirectional reception D. an overall reception signal increase
B. 8.1 dB C. 3.9 dB D. 10.0 dB 90. What is the usual electrical length of a driven element in an HF beam antenna?
86. What is driven element? A. ¼ wavelength A. Always the rearmost element B. Always the forward most element C. The element fed by the transmission line D. The element connected to the rotator 87. What is antenna bandwidth?
A. Antenna length divided by the number of elements B. The angle between the half-power radiation points C. The angle formed between two imaginary lines drawn through D. The frequency range over which an antenna can be expected to operate satisfactorily 88. To lengthen an antenna electrically, add a
B. ¾ wavelength C. ½ wavelength D. 1 wavelength 91. What happens to the bandwidth of an antenna as it is shortened through the use of loading coils?
A. It is increased B. It is decreased C. No change occurs D. It becomes flat 92. To electrically decrease the length of an antenna.
A. add an inductor in series B. add an inductor in parallel C. add a resistor in series
A. resistor B. battery C. condult
D. add a capacitor in series 93. Strong interference from one particular station can be eliminated by the use of
A. noise limiters B. squelch circuits C. negative feedback D. wave traps in the antenna circuitry 94. It is useful to refer to an isotropic radiator.
A. Antenna open circuit stops transmission B. An inductor of equal value must be added C. No change occurs to antenna D. Antenna resonant frequency increases 98. Where are the current nodes in a halfwave antenna?
A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio
A. At the ends B. At the center
C. when (in the northern hemisphere) directing the transmission
C. Three-quarters of the way from the feed point toward the end
D. when using a dummy load to tune a transmitter
D. One-half of the way from the feed point toward the end
95. A disadvantage of using a trap antenna.
99. For a shortened vertical antenna, where should a loading coil be placed to minimize losses and produce the most effective performance?
A. It will radiate harmonics B. It can only be used for single-bad operation C. It is too sharply directional at lower frequencies D. It must be neutralized 96. The input terminal impedance at the center of a folded dipole antenna is
A. As low as possible on the vertical radiator B. Near the center of the vertical radiator C. As close to the transmitter as possible D. At a voltage node 100. The effect of adding parasitic elements of a Hertz dipole is to
A. 72 Ω B. 300 Ω C. 50 Ω D. 73 Ω 97. When a capacitor is connected in series with a Marconi antenna?
A. make the antenna more omnidirectional B. reduce its resonant frequency C. increase the antenna’s power gain D. All of these 51. the base of the antenna
52. inductance in series
71. sky wave propagation
53. Dummy
72. isotropic antenna
54. 158 watts
73. quarter wavelength
55. 16
74. Resonant
56. By connecting an inductor in series with the antenna
75. Broadside array 76. a sphere
57. A vertical antenna which is a quarter-wavelength long
77. a hypothetical, omnidirectional antenna
58. its resonant frequency will be increased
78. All of these
59. 2.0 A
79. improved radiation efficiency
60. must have a vertical receiving antenna for the best reception
80. At the feed point
61. has a zero DC resistance to ground 62. both B and C 63. decrease 64. The antenna’s resonant frequency will increase 65. The field strength varies inversely as the distance from the antenna 66. both A and B 67. a bidirectional radiation pattern in the horizontal plane 68. vertical quarter-wavelength rod 69. 60 centimeters 70. doubled
81. Isotropic radiator 82. 6546 kHz 83. in the horizontal direction 84. add an inductor series 85. a more omnidirectional reception 86. The element fed by the transmission line 87. The frequency range over which an antenna can be expected to operate satisfactorily 88. coil 89. 3.9 dB 90. ½ wavelength 91. It is increased
92. add a capacitor in series 93. wave traps in the antenna circuitry 94. when comparing the gains of directional antennas 95. It will radiate harmonics 96. 300 Ω 97. Antenna resonant frequency increases 98. At the ends 99. Near the center of the vertical radiator 100. increase the antenna’s power gain
