Description : One of the following is very useful as a multiband HF receiving antenna. A. Parabolic antenna B. Elementary doublet C. Log-periodic D. Square loop
Last Answer : C. Log-periodic
Description : An antenna which is one-tenth wavelength long A. Hertzian dipole B. Loop antenna C. Marconi antenna D. Elementary doublet
Last Answer : D. Elementary doublet
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
Description : The standard reference antenna forthe directive gain isthe a. infinitesimal dipole b. isotropic antenna c. elementary doublet d. half-wave dipole
Last Answer : b. isotropic antenna
Description : It consists of a number of dipoles of equal size, equally spaced along a straight line with all dipoles fed in the same phase from the same source. A. Log-periodic antenna B. Yagi antenna C. End-fire array D. Broadside array
Last Answer : D. Broadside array
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 : 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 : Which antenna is not grounded at one end? A. Hertz B. Marconi C. Dipole D. Whip
Last Answer : C. Dipole
Description : A theoretical reference antenna that provides a comparison for antenna measurements. A. Marconi antenna B. Isotropic radiator C. Yagi-Uda array D. Whip antenna
Last Answer : B. Isotropic radiator
Description : Which antenna is not properly terminated? A. Resonant B. Non-resonant C. Isotropic D. Whip
Last Answer : A. Resonant
Description : An antenna with unity gain A. Rhombic B. Half-wave dipole C. Isotropic D. Whip
Last Answer : C. Isotropic
Description : Refers to a type of beam antenna which uses two or more straight elements arranged in line with each other. A. Dipole antenna B. Yagi antenna C. Whip antenna D. Rhombic antenna
Last Answer : B. Yagi antenna
Description : Antenna which is not properly terminated A. Isotropic B. Non-resonant C. Whip D. Resonant
Last Answer : D. Resonant
Description : This is a flexible vertical rod antenna commonly used on mobiles. A. Marconi B. Hertz C. Whip D. Ground plane
Last Answer : C. Whip
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 : Modulation in which the modulated wave is always present. A. Carrier modulation B. Front-end C. Continuous modulation D. Log-periodic modulation
Last Answer : C. Continuous modulation
Description : Two wires that are bent 90 degrees apart. A. Hertz B. Dipole C. Log-periodic D. Rhomic
Last Answer : B. Dipole
Description : Type of emission produced by one of the early radio transmitter in trains of damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in radio telegraph and having sidebands on its carrier. A. Digital emission B. Key emission C. Cycle emission D. Spark emission
Last Answer : D. Spark emission
Description : Which one is an antenna coupling unit? A. Coupler B. Diplexer C. Lecher wire D. Duplexer
Last Answer : B. Diplexer
Description : 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
Last Answer : B. 6546 kHz
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 single conductor running from the transmitter to the antenna. A. RG-8/U B. Single line wire C. Twin-lead D. MIcrostrip
Last Answer : B. Single line wire
Description : The band of light wavelengths that are too long to be seen by the human eye a. Amber b. Visible c. Infrared d. Ultraviolet
Last Answer : c. Infrared
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 : _____ of an antenna is a measure of how the antenna concentrates its radiated power in a given direction. A. Efficiency B. Power C. Gain D. Polarization
Last Answer : C. Gain
Description : 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
Last Answer : C. 100 μV/m
Description : The antenna radiates _____ polarized waves when the transmitter antenna is horizontally installed. A. Vertically B. negatively C. horizontally D. circularly
Last Answer : C. horizontally
Description : _____ is an open-ended slot antenna A. Helical antenna B. Rhombic antenna C. Notch antenna D. Cassegrain antenna
Last Answer : C. Notch antenna
Description : _____ is the horizontal pointing angle of an antenna A. Azimuth B. Angle of elevation C. Right angle D. Beamwidth
Last Answer : A. Azimuth
Description : A horizontal antenna is _____. A. vertically polarized B. horizontally polarized C. centrally polarized D. circularly polarized
Last Answer : B. horizontally polarized
Description : The polarization of a discone antenna is _____. A. Horizontal B. Vertical C. Omni D. Directional
Last Answer : B. Vertical
Description : Is the width of the range of wavelengths emitted by the light source a. Bandwidth b. Chromatic Dispersion c. Spectral width d. Beamwidth
Last Answer : c. Spectral width
Description : What are the electromagnetic radiations of wavelengths less than 300 angstroms? A. X-rays B. Ultraviolet rays C. Infrared D. Microwaves
Last Answer : A. X-rays
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 : Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? A. 1.35 cm and 1.7 mm B. 1.5 mm and 5 mm C. 1.35 dm and 1.7 cm D. 1.5 cm and 5mm
Last Answer : A. 1.35 cm and 1.7 mm
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 : Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? A. 1.35 cm and 1.7 mm B. 1.5 mm and 5mm C. 1.35 dm and 1.7cm D. 1.5 cm and 5 mm
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 : 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 : 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 : 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 : 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 : 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 : It is an average power of a radio transmitter supplied to the antenna transmission line taken during a long sufficient interval of time and compared with the lowest frequency encountered in the modulation ... operating conditions. A. Carrier power B. Rated power C. Mean power D. Peak envelop power
Last Answer : C. Mean power
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 : Which of the following statements regarding cilia is not correct ? (a) Cilia contain an outer ring of nine doublet microtubules surrounding two singlet microtubules. (b) The organised beating of ... (c) Cilia are hair-like cellular appendages. (d) Microtubules of cilia are composed of tubulin
Last Answer : (b) The organised beating of cilia is controlled by fluxes of Ca2+ across the membrane.
Description : Since the radiation pattern of a dipole is similar to that of a doublet, what will happen to the pattern if the length of the doublet is increased?
Last Answer : The pattern would flatten.
Description : The 1H NMR spectrum of propane will consist of? a. a triplet and a singlet b. a triplet and a quartet c. a doublet and a sextet d. a triplet and a septet
Last Answer : d. a triplet and a septet
Description : Listing of the date and time events, programs , equipment, test, malfunctions and corrections in communication system. A. File B. Documentation C. Reporting D. Log
Last Answer : D. Log
Description : Sound intensity level is ________. A. 10 log I/I(ref) B. 10 log I(ref)/I C. 30 log I/I(ref) D. 20 log I/I(ref)
Last Answer : A. 10 log I/I(ref)