Description : When microwave energy is passed through a piece of ferrite in a magnetic field, another effect occurs. If the frequency of the microwave energy is much greater than the electron wobble frequency, the plane of polarization of the wavefront is rotated. This is known as
Last Answer : Faraday Rotation Effect
Description : It is the ratio of the power density radiated in a particular direction to the power density radiated to the same point by a reference antenna, assuming both antennas are radiating the same amount of power
Last Answer : directive gain
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 : If energy is applied at the geometrical center of antenna, the antenna is said to be ___
Last Answer : center-fed
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 : Picture frames are repeated at the rate of ___ per second
Last Answer : . 30
Description : The final power amplifier in an FM transmitter usually operates class ___
Last Answer : C
Last Answer : 30
Description : Germanium diodes are used in AM detectors because ___
Last Answer : they minimize distortion from nonlinearit
Description : A mode where the entire magnetic field is in the transverse plane and has no portion parallel to the length axis.
Last Answer : TM mode
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 : The fields surrounding the antenna do not collapse their energy back into the antenna but rather radiate it out in space
Last Answer : radiation field
Description : It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates
Last Answer : . Radiation resistance
Description : The line bisecting the major lobe, or pointing from the center of the antenna in the direction of maximum radiation is called _____
Last Answer : line of shoot
Description : The radiation pattern of collinear and a broadside antenna is __
Last Answer : bidirectional
Description : Hertz antenna are predominantly used with frequencies above
Last Answer : 2MHz
Description : The point on the antenna where the transmission line is connected is called _____
Last Answer : feedpoint
Description : The discone antenna is
Last Answer : useful as a UHF receiving antenna
Description : It is the same with directive gain except that the total power fed to the antenna is used and the antenna efficiency is taken into account.
Last Answer : power gain
Description : A class A FM station is limited in antenna height of ______ feet above average terrain.
Last Answer : 2000
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 : The electric field lines in a plane perpendicular to the earth’s surface. A. Elliptical polarization B. Circular polarization C. Horizontal polarization D. Vertical polarization
Last Answer : D. Vertical polarization
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 : Plots of field strength or power density with respect to the value at a reference point.
Last Answer : relative radiation pattern
Description : The radiation pattern plotted in terms of electric field strength or power density
Last Answer : absolute radiation pattern
Description : The vertical field-scanning frequency is ______ Hz
Last Answer : 60
Description : In IPv6, when a datagram needs to be discarded in a congested network, the decision is based on the _______ field in the base header.
Last Answer : priority
Description : In IPv4, what is the value of the total length field in bytes if the header is 28 bytes and the data field is 400 bytes?
Last Answer : 428
Description : When satellite radio beam is aimed towards earth, it illuminates on the earth for an oval shaped area called
Last Answer : footprint
Description : A GEO is at the ________ orbit and revolves in phase with Earth.
Last Answer : equatorial
Description : Low-Earth-orbit (LEO) satellites have _____ orbits.
Last Answer : polar
Description : Most AM broadcasts employ ___ polarization while most FM broadcasts employ ___ polarization of the radio wave. A. vertical, vertical B. vertical, horizontal C. horizontal, vertical D. horizontal, horizontal
Last Answer : B. vertical, horizontal
Description : Consider the following statements: 1. In a direct-to-home (DTH) system, the viewer dish antenna picks up signals from the satellite directly. 2. Cable operators receive signal from the satellite on large community dish antennas and ... ? (a) Only 1 (b) Only 2 (c) Both 1 and 2 (d) Neither 1 nor 2
Last Answer : Ans:(c)
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 : 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 : 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 : One ofthe followingconsistsof nonresonant antennas: a.The rhombic antenna b. The folded dipole c. The end-fire array d. The broadside array
Last Answer : a.The rhombic antenna
Description : Define the following terms related to antennas; (i) Antenna resistance (ii) Directivity (iii) Antenna gain (iv) Power density
Last Answer : Antenna Resistance - The resistance of an antenna has two components: 1. Its radiation resistance due to conversion of power into electromagnetic waves 2. The resistance due to actual losses in the ... the transmitter power divided by the surface area of a sphere (4πR2) at that distance.
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 : 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 : In horizontal-dipole antenna, the polarization is A. in the vertical direction B. in the horizontal direction C. circular D. measured at the center of the antenna
Last Answer : B. in the horizontal direction
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 : 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