Description : _________ detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. A. Horn antenna B. LNA C. Satellite receiver D. Satellite dish
Last Answer : B. LNA
Description : ECE Board Exam March 1996 What is the purpose of the receiver's squelch circuit? A. To overcome fluctuations in the level the RF signal arriving at the receiver antenna B. To prevent ... signals D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal
Last Answer : D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal
Description : What is meant by referring to electromagnetic waves as having circular polarization? A. The electric field is bent into a circular shape. B. The electric field rotates C. The electromagnetic wave continues to circle the earth D. The electromagnetic wave has been generated by a quad antenna
Last Answer : B. The electric field rotates
Description : Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. AF amplifier B. Antenna C. Detector D. Crystal
Last Answer : B. Antenna
Description : A device that radiates electromagnetic energy and or intercepts electromagnetic radation. A. Antenna B. Transmitter C. Transmission line D. Transceiver
Last Answer : A. Antenna
Description : Conversion of sound energy into electrical energy is done by – (1) Solar cell (2) Gramophone (3) Microphone (4) Loudspeaker
Last Answer : (3) Microphone Explanation: Conversion of sound energy into electrical energy is done by microphone.
Description : Conversion of sound energy into electrical energy is done by (1) Solar cell (2) Gramophone (3) Microphone (4) Loudspeaker
Last Answer : Microphone
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 : The device which converts sound energy into electrical enemy is called – (1) Amplifier (2) Speaker (3) Microphone (4) Transmitter
Last Answer : (3) Microphone Explanation: A microphone converts sound energy to electrical energy this energy level is used as an output using same energy level, amplified or it could be used to record those ... coil within a strong magnetic field. The induced current duplicates the frequency of the sound wave.
Description : The device which converts sound energy into electrical energy is called (1) Amplifier (2) Speaker (3) Microphone (4) Transmitter
Description : 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
Last Answer : D. The direction of the electric field vector
Description : What type of transmission is radiated from an aircraft’s radio altimeter antenna? A. An amplitude modulated continuous wave B. A pulse position modulated UHF signal C. A differential phase shift keyed UHF signal D. A frequency modulated continuous wave
Last Answer : D. A frequency modulated continuous wave
Description : _______ detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. A. Feedhorn B. Satellite dish C. Satellite receiver D. LNB
Last Answer : D. LNB
Description : What is a device that detects both vertically and horizontally polarized signals simultaneously? A. Orthomode transducer B. Crystal detector C. Optoisolator D. Isomode detector
Last Answer : A. Orthomode transducer
Description : ______ is a device that detects both vertically and horizontally polarized signals simultaneously. A. Crystal B. Orthomode transducer C. Light transducer D. Optoisolator
Last Answer : B. Orthomode transducer
Description : When no signal is being received, the loudspeaker is not entirely silent as a result of the presence of A. parasitic oscillations in some of the receiver stages. B. negative feedback in each stage. C. spurious frequencies as a result of improper neutralization. D. internal receiver noise.
Last Answer : D. internal receiver noise.
Description : A loudspeaker cabinet has an internal volume of 5,184 in3 (84,950 cm3 ). It has a port area on the baffle of 50 in2 (322.58cm2 ) and a thickness of 0.70 in (18 mm). What is the Helmholtz resonance, in hertz, of this loudspeaker enclosure? A. 250 Hz B. 245 Hz C. 240 Hz D. 255 Hz
Last Answer : C. 240 Hz
Description : What is the relationship in degrees of the electrostatic and electromagnetic fields of an antenna? A. 0 degree B. 45 degrees C. 90 degrees D. 180 degrees
Last Answer : C. 90 degrees
Description : 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
Last Answer : A. At the ends
Description : At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? A. Minimum voltage and minimum current B. Equal voltage and current C. Minimum voltage and maximum current D. Maximum voltage and minimum current.
Last Answer : D. Maximum voltage and minimum current.
Description : If the modulation index of an AM wave is doubled, the antenna current is also doubled, the AM system being used is A. A5C B. A3J C. A3H D. A3
Last Answer : B. A3J
Description : A receiver is located 64 km from a space wave transmitting antenna that is 100 meters high. Find the required height of the receiving antenna. A. 36 meters high B. 64 meters high C. 100 meters high D. 182.25 meters high
Last Answer : A. 36 meters high
Description : If a transmitting antenna is 100 meters high and a separate receiving antenna is 64 meters high, what is the maximum space wave communication distance possible between them? A. 18 km B. 72 km C. 164 km D. 656 km
Last Answer : B. 72 km
Description : Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? A. 1.35 cm and 1.7 mm B. 5 mm and 2.5 mm C. 5 cm and 2.5 cm D. 1.35 mm and 1.7 μm
Last Answer : B. 5 mm and 2.5 mm
Description : ____ is defined as any radiation of energy by means of electromagnetic wave. A. Emission B. Radiation C. Radio D. Broadcasting
Last Answer : A. Emission
Description : Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? A. 1.35 mm and 1.7 μm B. 1.35 cm and 1.7 mm C. 5 cm and 2.5 cm D. 5 mm and 2.5 mm
Last Answer : D. 5 mm and 2.5 mm
Description : What are electromagnetic waves? A. Alternating currents in the core of an electromagnet B. A wave consisting of two electric fields at right angles to each other C. A wave consisting of an electric field ... to each other D. A wave consisting of two magnetic fields at right angles to each other
Last Answer : C. A wave consisting of an electric field and a magnetic field at right angles to each other
Description : What are electromagnetic waves? A. A wave consisting of two magnetic fields at right angles to each other B. A wave consisting of an electric field and a magnetic field at right angles to each ... core of an electromagnet D. A wave consisting of two electric fields at right angles to each other
Last Answer : B. A wave consisting of an electric field and a magnetic field at right angles to each other.
Description : An electromagnetic wave is ________ polarized when the electric field lies wholly in one plane containing the direction of propagation. A. Horizontally B. Linearly C. Circularly D. Vertically
Last Answer : B. Linearly
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 : Electromagnetic wave travel at __________ in free space. A. 300,000 km/sec B. 100,000 km/ sec C. 400,000 km/sec D. 200km/sec
Last Answer : A. 300,000 km/sec
Description : An electromagnetic wave consists of A. a magnetic field only B. both electric and magnetic fields C. an electric field only D. non-magnetic field only
Last Answer : B. both electric and magnetic fields
Description : The device that converts digital signals to analog signals at the start of long distance transmissions is (1) peripheral (2) modem (3) telephone (4) antenna
Last Answer : modem
Description : The antenna efficiency of an HF grounded vertical antenna can be made comparable to that of a half-wave antenna A. By installing a good ground radial system B. By isolating the coax shield from ground C. By shortening the vertical D. By lengthening the vertical
Last Answer : A. By installing a good ground radial system
Description : 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
Last Answer : D. wave traps in the antenna circuitry
Description : Where are the voltage nodes in a half-wave antenna? 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
Last Answer : D. At the feed point
Description : The rhombic antenna is primarily used for A. ground wave propagation B. space wave propagation C. ionosphere scatter propagation D. sky wave propagation
Last Answer : D. sky wave propagation
Description : An antenna with unity gain A. Rhombic B. Half-wave dipole C. Isotropic D. Whip
Last Answer : C. Isotropic
Description : _____ is an antenna with a number of half-wave antenna on it. A. Antenna array B. Tower C. Omni-directional D. Rhombic
Last Answer : A. Antenna array
Description : For a space wave transmission, the radio horizon distance of a receiving antenna with a height of 64 meters is approximately A. 8 km B. 32 km C. 64 km D. 256 km
Last Answer : B. 32 km
Description : What is the resultant field strength at the receiving antenna in space wave propagation under case 2? A. 0 B. ξd C. 2ξd D. 3ξd
Last Answer : C. 2ξd
Description : The polarization of a radio wave: A. Is perpendicular to the electrostatic field of the antenna B. Is the same direction as the electrostatic field of the antenna. C. Is the same direction ... field of the antenna. D. Is perpendicular to both the electrostatic and magnetic fields of the antenna.
Last Answer : B. Is the same direction as the electrostatic field of the antenna.
Description : For a space wave transmission, the radio horizon distance of a transmitting antenna with a height of 100 meters is approximately: A. 10 km B. 40 km C. 100 km D. 400 km
Last Answer : B. 40 km
Description : Where the voltage node of a half-wave antenna does exists? A. At feed point B. Near the center C. At center D. Near the feed point
Last Answer : A. At feed point
Description : How can the antenna efficiency of an HF grounded vertical antenna be made comparable to that of a half-wave antenna? A. By lengthening the vertical B. By installing a good ground radial system C. By shortening the vertical D. By isolating the coax shield from ground
Last Answer : B. By installing a good ground radial system
Description : Radio wave concentration in the direction of the signal emitted by a directional antenna. A. Back lobe radiation B. Side lobe radiation C. Major lobe radiation D. Transmitted signal
Last Answer : C. Major lobe radiation
Description : The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction. A. Peak envelope power B. ERP C. Rated power D. Carrier power’
Last Answer : B. ERP
Description : Unity gain antenna A. Isotropic B. Rhombic C. Half-wave dipole D. Dummy
Last Answer : A. Isotropic
Description : A type of array antenna which consists of one half-wave driven dipole, one reflector and one director A. Hertzian dipole B. Yagi-uda C. Broadside collinear D. Log periodic dipole array
Last Answer : B. Yagi-uda
Description : ECE Board Exam March 1996 The standard reference antenna for the directive gain is ___________. A. elementary doublet B. isotropic antenna C. half-wave dipole D. infinitesimal dipole
Last Answer : B. isotropic antenna