Description : Whichofthe followingantennasis best excited fromawaveguide? a. Biconical b.Horn c. Helical d. Discone
Last Answer : b.Horn
Description : An antenna with very high gain and very narrow beamwidth. A. Helical antenna B. Discone antenna C. Horn antenna D. Parabolic dish antenna
Last Answer : D. Parabolic dish antenna
Description : 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
Last Answer : A. Marconi antenna
Description : Which antenna is not a wideband? A. Discone B. Folded dipole C. Helical D. Marconi
Last Answer : D. Marconi
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 : Indicate the antenna thatisnotwideband: a. Discone b. Folded Dipole c. Helical d. Marconi
Last Answer : d. Marconi
Description : Discone radiation pattern is ______. A. omnidirectional/vertical polarized B. unidirectional C. bidirectional D. figure of eight
Last Answer : A. omnidirectional/vertical polarized
Description : What is the polarization of a discone antenna? A. Vertical B. Horizontal C. Circular D. Spiral
Last Answer : A. Vertical
Description : Radiation pattern of a discone. A. Unidirectional B. Bidirectional C. Omnidirectional D. Figure of eight
Last Answer : C. Omnidirectional
Description : The polarization of a discone antenna is _____. A. Horizontal B. Vertical C. Omni D. Directional
Last Answer : B. Vertical
Description : Helical antennas are oftenused forsatellite trackingatVHFbecauseof a. troposcatter b. superrefraction c. ionospheric refraction d.theFaradayeffect
Last Answer : d.theFaradayeffect
Description : Write the application of the following antennas: 1) Rectangular antenna 2) Dish antenna 3) Horn antenna 4) Loop antenna 5) Yagi-Uda antenna.
Last Answer : Applications: 1.Rectangular antenna i)Used in Mobile and satellite communication ii)Used in Global Positioning System iii) Used for Radio Frequency Identification (RFID) iv) Radar Dish ... antenna. 2. Yagi-Uda antenna is used in conditional Access System (CAS) at the decryptor.
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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : When speaking of antennas. ______ is a section which would be a complete antenna by itself. A. image B. top loading C. bay D. quarterwave
Last Answer : C. bay
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 : 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 : 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 : 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 : 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 : 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 : 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 : A dielectric waveguide for the propagation of electromagnetic energy at light frequencies a. Stripline b. Microstrip c. Laser beam d. Fiber optics
Last Answer : d. Fiber optics
Description : Proposed the use of clad glass fiber as a dielectric waveguide a. Karpon and Keck b. Karpon and Bockham c. Bockham and Kao d. Kao and Keck
Last Answer : c. Bockham and Kao
Description : What device in a waveguide system used for stopping or diverting electromagnetic wave as desired? A. Mechanical switch B. Electric switch C. Push-button switch D. Waveguide switch
Last Answer : D. Waveguide switch
Description : A waveguide passive component that brings a smooth change in the direction of axis maintained perpendicular to the plane of polarization? A. L bend B. H bend C. T bend D. X bend
Last Answer : B. H bend
Description : Which of the following is not a bounded medium? A. Coaxial line B. Two-wire line C. Waveguide D. Free space
Last Answer : D. Free space
Description : Best reason for pressurizing waveguides with dry air A. To maintain propagation B. To maintain temperature of the waveguide C. To reduce the possibility of internal arcing D. To increase the speed of propagation
Last Answer : C. To reduce the possibility of internal arcing
Description : Propagation mode of microwave in a waveguide is known as _______. A. TM B. TE C. SW D. TEM
Last Answer : B. TE
Description : The advantage of periscope antenna in microwave A. Minimize interference to and from other neighboring stations B. Shorten waveguide link C. Reduce tower height D. All of these
Last Answer : B. Shorten waveguide link
Description : When electromagnetic wave are propagated through a waveguide, they A. are reflected from the walls but do not travel along them B. travel along all four walls of the waveguide C. travel along the broader walls of the guide D. travel through the dielectric without touching the walls
Last Answer : A. are reflected from the walls but do not travel along them
Description : Proposed the use of a clad glass fiber as a dielectric waveguide. A. Kao and Keck B. Karpon and Keck C. Karpon and Bockham D. Bockham and Kao
Last Answer : D. Bockham and Kao
Description : The first laser emitted a. Pulses of 694 nm red light b. A continuous red beam c. Pulses of white light from a helical flashlamp d. Spontaneous emission
Last Answer : a. Pulses of 694 nm red light