Description : What quarterwave transformer will match a 100Ω line to an antenna whose value is 175Ω? A. 132.29 Ω B. 150 Ω C. 16.58 Ω D. 137.5 Ω
Last Answer : A. 132.29 Ω
Description : Indicate which of the following reasons for using metal counterpoise with antennas is false. A. Impossibly of a good ground connection B. Protection of personnel working underneath C. Provision of an earth for the antenna D. Rockiness of the ground itself
Last Answer : B. Protection of personnel working underneath
Description : Top loading is used in an antenna in order to increase its ______. A. practical height B. beamwidth C. effective height D. input capacitance
Last Answer : C. effective height
Description : One of the following makes an antenna physically long but electrically short A. Adding L in series B. Adding C in series C. Top loading D. Both A and C
Last Answer : B. Adding C in series
Description : 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
Last Answer : D. improved radiation efficiency
Description : What makes an antenna physically long but electrically short? A. Top loading B. Adding C in series C. Adding L in series D. All of these
Description : Top loading is used in an antenna in order to increase its ___________. A. input capacitance B. beamwidth C. bandwidth D. effective height
Last Answer : D. effective height
Description : Factors that determine the radiation resistance of an antenna A. Transmission line length and height of antenna B. The location of the antenna with respect to nearby objects C. It is a constant for all antennas since it is physical D. Sunspot activity and the time of day
Last Answer : B. The location of the antenna with respect to nearby objects
Description : 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
Last Answer : C. increase the antenna’s power gain
Description : What is the effect of adding a capacitor in series with an antenna? A. The antenna’s resonant frequency will increase B. The antenna’s resonant frequency will decrease C. The antenna will be physically 5% longer than its electrical length D. A capacitor is never added in series with an antenna
Last Answer : A. The antenna’s resonant frequency will increase
Description : Which of the following antennas receive signals in the horizontal plane equality well from all directions? A. Horizontal Hertz antenna B. Vertical loop antenna C. Vertical Yagi antenna D. A vertical antenna which is a quarter-wavelength long
Last Answer : D. A vertical antenna which is a quarter-wavelength long
Description : 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
Last Answer : B. By focusing the radiated energy in one desired direction
Description : Which of the following antennas require good grounding? A. Yagi antenna B. Hertz antenna C. Marconi antenna D. Isotropic antenna
Last Answer : C. Marconi antenna
Description : Which of the following antennas receives signals equally well from all directions in a horizontal plane? A. Hetz antenna B. Vertical Marconi antenna C. Yagi antenna D. Helical antenna
Last Answer : B. Vertical Marconi antenna
Description : In shipboard satellite dish antennas system, azimuth is referred as the _______. A. 0 to 90 degrees B. Vertical aiming of the antenna C. North to East D. Horizontal aiming of the antenna
Last Answer : D. Horizontal aiming of the antenna
Description : What is the gain of four identically polarized antennas stacked one above the other and fed in phase? A. 3 dB over the gain of one antenna B. 10 dB over the gain of one antenna C. 4 dB over the gain of one antenna D. 6 dB over the gain of one antenna
Last Answer : D. 6 dB over the gain of one antenna
Description : 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
Last Answer : B. Near the center of the vertical radiator
Description : 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
Last Answer : A. It is increased
Description : 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
Last Answer : C. 200 kph
Description : Known as the technique for adding a series inductor at or near the center of an antenna element in order to cancel the capacitive reactance of an antenna. A. Dipole B. Center loading C. Reflector D. loading coil
Last Answer : D. loading coil
Description : What is the estimated medium wind loading in the Philippines for antenna tower design? A. 200 kph B. 250 kph C. 300 kph D. 100 kph
Last Answer : A. 200 kph
Description : 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
Last Answer : B. 158 watts
Description : ______ is an antenna array which is highly directional at right angles to the plane of the array? A. Broadside array B. End-fire array C. Turnstile array D. Log-periodic array
Last Answer : A. Broadside array
Description : 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
Last Answer : A. 3.3 times
Description : The length of a Marconi antenna to operate with 985 kHz is ______. A. 200 ft B. 500 ft C. 250 ft D. 999 ft
Last Answer : C. 250 ft
Description : ______ is the measurement of a unilateral antenna properties of directivity A. Phase angle B. Antenna gain C. Beamwidth D. Bandwidth
Last Answer : C. Beamwidth
Description : The antenna current is doubled when the modulation index is doubled in ______ AM system. A. A5C B. A3J C. A3 D. A3H
Last Answer : B. A3J
Description : The stability of transmitted signal from a simple Hartley oscillator single transmitter which is coupled to and antenna wire affected by ______. A. Chirping of oscillator B. Closer coupling between the oscillator and the antenna. C. Location of antenna D. Material of antenna
Last Answer : B. Closer coupling between the oscillator and the antenna.
Description : A helical antenna is used for satellite tracking because of ______. A. Broad bandwidth B. Good front-to-back C. Maneuverability D. Circular polarization
Last Answer : D. Circular polarization
Description : ______ is the first component of any MATV system to received broadcast signals. A. Receiver B. Antenna C. Filter D. Transmitter
Last Answer : B. Antenna
Description : When antennas are closed to the ground, _______ polarization is ideal A. horizontally polarized B. vertically polarized C. circularly polarized D. both A and B
Last Answer : B. vertically polarized
Description : Which of the following antennas is best excited from a waveguide? A. Biconical B. Horn C. Helical D. Discone
Last Answer : B. Horn
Description : Good grounding is important for A. horizontal antennas B. broadside array antennas C. vertical antennas D. Yagi-Uda antennas
Last Answer : C. vertical antennas
Description : It is useful to refer to an isotropic radiator. 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
Last Answer : A. when comparing the gains of directional antennas
Description : 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
Last Answer : A. a more omnidirectional reception
Description : Which of the following antennas is used for testing and adjusting a transmitter for proper modulation, amplifier operation and frequency accuracy? A. Elementary B. Real C. Isotropic D. Dummy
Last Answer : D. Dummy
Description : All elements in a beam _____ antennas are in line A. collinear B. yagi C. broadside array D. log-periodic
Last Answer : A. collinear
Description : In what range of frequencies are most omnidirectional horizontally polarized antennas used? A. VHF, UHF B. VLF, LF C. SH, EHF D. MF, HF
Last Answer : A. VHF, UHF
Description : The radiation patterns of earth coverage antennas have a beamwidth of approxiamately A. 21˚ B. 5˚ C. 17˚ D. 35˚
Last Answer : C. 17˚
Description : How does spatial isolation technique in satellite communications avoid interference? A. Use of different polarity antennas B. Use of different types of antennas C. Employment of highly directional spot-beam antennas D. Use of low gain antennas
Last Answer : C. Employment of highly directional spot-beam antennas
Description : When is it useful to refer to an isotropic radiator? A. When comparing the gains of directional antennas B. When testing a transmission line for standing wave ratio C. When (in the northern ... ) directing the transmission in a southerly direction D. When using a dummy load to tune a transmitter
Last Answer : A. When comparing the gains of directional antennas
Description : Which of the following refers to the smallest beam of a satellite antenna’s radiation pattern A. Global beam B. Spot beam C. Zone beam D. Hemispheric beam
Last Answer : B. Spot beam
Description : Space diversity transmission means transmitting and receiving on _______. A. Two or more antennas operating on two different frequencies B. Two or more identical frequencies C. Two or more antennas operating on the same frequency D. Two or more different frequency
Last Answer : C. Two or more antennas operating on the same frequency
Description : Which of the following refers to the smallest beam of satellite antenna’s radiation pattern? A. Hemispheric beam B. Spot beam C. Zone beam D. Global beam
Description : Two or more antennas separated by 9 wavelengths are used. A. Hybrid diversity B. Space diversity C. Polarized diversity D. Frequency diversity
Last Answer : B. Space diversity
Description : Space diversity transmission means transmitting and receiving on A. two or more antennas operating on two different frequencies B. two or more identical frequencies C. two or more different frequencies D. two or more antennas operating on the same frequencies
Last Answer : D. two or more antennas operating on the same frequencies
Description : What is the free space loss, in dB, between two microwave parabolic antennas 38.0 kilometer apart operating at 7.0 GHz? A. 145.6 dB B. 138.5 dB C. 135.5 dB D. 140.89 dB
Last Answer : D. 140.89 dB
Description : ECE Board Exam March 1996 When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ________ wave. A. space or direct B. ground C. surface D. sky
Last Answer : A. space or direct
Description : The current maximum in a Marconi antenna is found at 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
Last Answer : A. the base of the antenna
Description : What is the meaning of forward power? A. The power traveling from the transmitter to the antenna. B. The power radiated from the top of an antenna system. C. The power produced during the positive half of an RF cycle. D. The power used to drive a linear amplifier.
Last Answer : A. The power traveling from the transmitter to the antenna.