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 ho w much does the radiated power increase?
8. Gain of a half-wave dipole antenna over isotropic.
A. 3.3 times B. 10.89 times C. 9.9 times D. 6.6 times
A. image B. top loading C. bay D. quarterwave
A. VHF, UHF B. VLF, LF C. SH, EHF D. MF, HF
A. end fire array B. critical phased array C. broadband array D. wideband array
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?
6. A device that converts high frequency current curren t into electromagnetic wave.
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
5. If the current ratios of the two or more elements must be held 5% and the phase angle to 3° the antenna ante nna is called call ed a
A. Minor lobes B. Null C. Antenna patterns D. Major lobes
10. What is the gain of the Hertzian dipole over isotropic antenna?
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.
3. When speaking of antennas. ______ is a section which would be a complete antenna by by itself.
B. Folded dipole C. End-fire array D. Yagi-Uda antenna
A. Void antenna B. Dummy antenna C. Hertzian antenna D. Isotropic antenna
13. The best solution to fading is _____.
A. Antenna B. Loudspeaker C. Microphone D. Transducer
A. space diversity B. frequency diversity C. polarization diversity D. wavelength diversity
7. Which is a non-resonant antenna?
A. Rhombic antenna
14. _____ is the amount of uncertainty in a system of symbols
A. Bandwidth B. Enthalpy C. Entropy D. Quantum
21. _____ is an antenna with a number of halfwave antenna on it.
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
22. Which antenna radiates an omnidirectional pattern in the horizontal plane with vertical polarization?
16. Top loading is used in an antenna in order to increase its ______.
A. practical height B. beamwidth C. effective height D. input capacitance
A. vertically polarized B. horizontally polarized C. centrally polarized D. circularly polarized
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
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. Helical antenna B. Discone antenna C. Horn antenna D. Parabolic dish antenna
24. What determines antenna polarization?
18. All elements in a beam _____ antennas are in line
A. Marconi antenna B. Discone antenna C. Horn antenna D. Helical antenna
23. An antenna with very high gain and very narrow beamwidth.
17. A horizontal antenna is _____.
A. Antenna array B. Tower C. Omni-directional D. Rhombic
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?
34. How will you increase the gain of an antenna?
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
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 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
30. Which antenna is a properly terminated? 37. What is the gain of isotropic antenna?
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
38. Which of the following improves im proves antenna directivity?
32. What is the theoretical gain of a Hertzian dipole?
A. 1.76 dB B. 2.15 dB C. 3 dB D. 0 dB
A. Rhombic B. Half-wave dipole C. Isotropic D. Whip
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.
33. An antenna with unity gain
A. 10 B. 1 C. 10 D. 100
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?
47. _____ of an antenna is a measure of how the antenna concentrates its radiated power in a given 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 m 2 C. 2.088 m2
A. the base of the antenna B. the center of the antenna C. some point between the base and the center of the antenna D. the top of the antenna
52. If an antenna is too short for the wavelength being used, the effective length can be increased i ncreased by adding:
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
51. The current maximum in a Marconi antenna is found at
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. End effect B. Flywheel effect C. Skin effect D. Capture effect
49. Harmonic suppressor connected to an antenna.
A. Efficiency B. Power C. Gain D. Polarization
48. Shortening effect of an antenna that makes it appear as if it were 5% longer.
D. 4.088 m2
A. capacitance in series 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 fr equency accuracy?
A. Elementary 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 B. 158 watts C. 200 watts D. 400 watts
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?
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 D. By connecting an inductor in series with the antenna
A. Horizontal Hertz antenna B. Vertical loop antenna C. Vertical Yagi antenna D. A vertical antenna which is a quarter-wavelength long
A. has maximum RF impedance to ground at its feedpoint 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
58. If the length of a Hertz dipole is decreased
A. has maximum radiation in a vertical direction B. must have a horizontal receiving antenna for the best reception C. must use a receiving antenna for the best reception D. must have a vertical receiving antenna for the best reception
61. A shunt-fed quarter-wavelength Marconi antenna
57. Which of the following antennas receive r eceive signals in the horizontal plane equality well from all directions?
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. 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.
A. decrease its directivity B. increase its directivity C. give the antenna unidirectional properties D. both B and C
63. If the length of an antenna is changed from 2.5 meters to 2.8 meters, its resonant frequency fr equency will
A. increase B. depend on the velocity factor so the resonant frequency can either be increased or decreased C. will be unchanged D. decrease
64. What is the effect of adding a capacitor in series with an antenna?
68. In order to get maximum radiation to all surrounding points in the horizontal plane, the antenna used is a
A. The antenna’s resonant frequency will increase B. The antenna’s resonant frequency will decrease C. The antenna will be physically ph ysically 5% longer than its electrical length D. A capacitor is never added in series with an antenna
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 C. The field strength remains constant regardless of the distance from the antenna D. The field strength varies inversely as the distance from the antenna
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 D. both A and B
67. A vertical loop antenna has a
A. 60 centimeters 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. doubled B. halved C. multiplied by a factor of four D. divided by a factor of four
71. The rhombic antenna is primarily used for
66. Stacking elements in a transmitting antenna system
A. vertical loop 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?
65. How does the electric field strength of a standard broadcast station vary with the distance from the antenna?
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
A. ground wave propagation 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
73. Actual height of antenna should be at least
A. one wavelength B. half wavelength
C. quarter wavelength D. three-fourth wavelength
74. Which antenna is not properly terminated?
80. Where are the voltage nodes in a half-wave antenna?
A. Resonant B. Non-resonant C. Isotropic D. Whip
75. ______ is an antenna array which is highly directional at right angles to the plane of the array?
81. A theoretical reference antenna that provides pr ovides a comparison for antenna measurements.
A. Broadside array 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 C. a unidirectional cardioid D. a parabola
A. At the ends 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
A. Marconi antenna B. Isotropic radiator C. Yagi-Uda array D. Whip antenna
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?
A. 727 kHz B. 6546 kHz C. 436 kHz D. 6.546 kHz
77. An isotropic radiator is
A. in the northern hemisphere B. an antenna high enough in the air C. an antenna whose directive pattern is substantially incredible D. a hypothetical, omnidirectional antenna
78. The purpose of stacking elements on an antenna.
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
A. lower quality factor B. greater structural strength C. higher losses D. improved radiation efficiency
83. In horizontal-dipole antenna, the polarization polari zation is
A. in the vertical direction 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 B. add a capacitor in series C. add an inductor series D. add a resistor is series
85. Stacking antennas at various angles results in
A. a more omnidirectional reception B. a more unidirectional reception C. a more omnidirectional reception D. an overall reception signal increase
86. What is driven element?
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 bet ween two imaginary lines drawn through D. The frequency range over which an antenna can be expected to operate satisfactorily
93. Strong interference from one particular station can be eliminated by the use of
88. To lengthen an antenna electrically, add a
A. resistor B. battery C. condult D. coil
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. add an inductor in series B. add an inductor in parallel C. add a resistor in series D. add a capacitor in series
A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio C. when (in the northern hemisphere) directing the transmission D. when using a dummy load to tune a transmitter
95. A disadvantage of using a trap antenna. 89. What is the gain of an antenna over a halfwavelength dipole when it has 6 dB gain over an isotropic radiator?
A. 6.0 dB 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?
96. The input terminal impedance at the center of a folded dipole antenna is
A. ¼ wavelength 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. 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
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. 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 half-wave antenna?
A. At the ends B. At the center C. Three-quarters of the way from the feed point toward the end D. One-half of the way from the feed point toward the end
99. For a shortened vertical antenna, where should a loading coil be placed to minimize losses and produce the most effective performance?
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. make the antenna more omnidirectional B. reduce its resonant frequency C. increase the antenna’s power gain D. All of these
