Description : How is directivity of a collinear array affected when the number of elements is increased?
Last Answer : Directivity increases.
Description : What two main advantages of a parasitic array can be obtained by combining a reflector and a director with the driven element?
Last Answer : Increased gain and directivity.
Description : What is the advantage of adding parasitic elements to a Yagi array?
Last Answer : Increased gain.
Description : What are the disadvantages of the parasitic array?
Last Answer : Their adjustment is critical and they do not operate over a wide frequency range.
Description : The parasitic array can be rotated to receive or transmit in different directions. What is the name given to such an antenna?
Last Answer : Rotary array.
Description : The parasitic element of an antenna system will A. decrease its directivity B. increase its directivity C. give the antenna unidirectional properties D. both B and C
Last Answer : D. both B and C
Description : Which of the following improves antenna directivity? A. Driven element B. Reflector element C. Director element D. Parasitic element
Last Answer : D. Parasitic element
Description : The directivity pattern of an isotropic radiator is A. a figure-8 B. a sphere C. a unidirectional cardioid D. a parabola
Last Answer : B. a sphere
Description : Stacking elements in a transmitting antenna system A. increases the field strength at the receiving antenna B. increases the directivity of the transmitter antenna C. decrease the size of the lobe in the radiation pattern D. both A and B
Last Answer : D. both A and B
Description : What determines the ability of radar to determine the bearing to a target? A. Speed of light B. Speed of target C. Antenna directivity D. Frequency of signal
Last Answer : C. Antenna directivity
Description : In order to get maximum radiation to all surrounding points in the horizontal plane, the antenna used is a A. vertical loop B. vertical quarter-wavelength rod C. array which includes parasitic elements D. a horizontal Hertz dipole
Last Answer : B. vertical quarter-wavelength rod
Description : The reflector and director of an antenna array are considered as A. Parasitic elements B. Transcendental elements C. Feed-points D. Driven elements
Last Answer : A. Parasitic elements
Description : Whichoneofthe followingterms doesnot applyto theYagi-Uda array? a. Good bandwidth b. Parasitic elements c. Folded dipole d.Highgain
Last Answer : d.Highgain
Description : How do socio-economic factors determine the distribution pattern of population in India? Discuss. -Geography
Last Answer : (i) Evolution of settled agricultural development. (ii) Pattern of human settlement. (iii) Development of transport network. (iv) Industrialisation and urbanisation
Description : ________ command gives an array of object in 3D modeling a.Extrude b.Revolve c.Pattern d.All of the above
Last Answer : c.Pattern
Description : . What are two of the three physical factors that determine the values of capacitance and inductance of a transmission line?
Last Answer : (1) Type of line used, (2) dielectric in the line, and (3) length of line.
Description : What two factors determine the frequency of the output voltage of an alternator?
Last Answer : Speed of rotation and number of poles.
Description : . What three factors determine the amplitude of the voltage induced into a stator winding?
Last Answer : The amplitude of the primary voltage, the turns ratio, and the angular displacement between the rotor and the stator winding.
Description : What three main factors determine the amount of refraction in the ionosphere?
Last Answer : (a) density of ionization of the layer (b) frequency (c) angle at which it enters the layer
Description : The way a magnetic head will be used determines how it is constructed. Name three factors that determine the final construction of a magnetic head.
Last Answer : a. Type of head (record, reproduce, or erase). b. Frequencies it will record or reproduce. c. Whether it will be used on a single or multitrack recorder.
Description : What factors determine the rigidity of a gyro?
Last Answer : Rotor speed, weight, shape.
Description : What factors determine the direction of rotation in a dc motor?
Last Answer : Direction of armature current, and direction of magnetic flux in field.
Description : What factors determine the value of the multiplier resistor?
Last Answer : The current required for full-scale deflection, and the range of the voltage to be measured.
Description : What three factors determine the type, size, and shape of an antenna?
Last Answer : Frequency of operation of the transmitter, amount of power to be radiated, and general direction of the receiving set.
Description : Which abiotic factors would a parasitic strangler fig and its host tree compete for?
Last Answer : i dont know
Description : When more than two elements are used in a broadside array, how are the elements arranged?
Last Answer : Parallel and in the same plane.
Description : The broadside array consists of a flat reflector and what other elements?
Last Answer : Two or more half-wave dipoles.
Description : The Yagi antenna is an example of what type of array?
Last Answer : Multielement parasitic array.
Description : To maintain the required balance of phase relationships and critical feeding, how must the end-fire array be constructed?
Last Answer : Symmetrically.
Description : Where does the major lobe in the end-fire array occur?
Last Answer : Along the major axis
Description : What are some disadvantages of the end-fire array?
Last Answer : Extremely low radiation resistance, confined to one frequency, and affected by atmospheric conditions.
Description : As the spacing between elements in a broadside array increases, what is the effect on the major lobes?
Last Answer : They sharpen.
Description : How can the frequency range of a collinear array be increased?
Last Answer : By increasing the lengths of the elements of the array.
Description : Why is the number of elements used in a collinear array limited?
Last Answer : As more elements are added, an unbalanced condition in the system occurs which impairs efficiency.
Description : What is the maximum number of elements ordinarily used in a collinear array?
Last Answer : Four.
Description : Themaindisadvantage ofthe two-hole directional coupleris a. low directional coupling b. poor directivity c. high SWR d.narrowbandwidth
Last Answer : d.narrowbandwidth
Description : What is the ratio of the maximum radiation intensity to the average radiation intensity? A. Aperture gain B. Directivity gain C. Transmission gain D. Power gain
Last Answer : B. Directivity gain
Description : Comparing the signal strength arriving at the driven element from the desired direction to the signal strength reaching the driver from the opposite direction. A. Directivity B. Sensitivity C. Beamwidth D. Front-to-back ratio
Last Answer : D. Front-to-back ratio
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 : 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 : Define the following terms: (i) Polarization (ii) Antenna gain (iii)Antenna resistance (iv)Directivity
Last Answer : i) Polarization:- It is defined as the direction of electric field vector in the EM wave radiated by the transmitting antenna. ii) Antenna Gain:- Antenna gain is defined as the ratio of ... in only one direction in which the radiation is maximum. That is directivity = Max. directive gain
Description : An antenna has a radiation resistance of 72 Ω a loss resistance of 8 Ω and a power gain of 16. Find efficiency and directivity.
Last Answer : An antenna has a radiation resistance of 72 Ω a loss resistance of 8 Ω and a power gain of 16. Find efficiency and directivity.
Last Answer : A higher directivity is specified by High gain low BW.
Description : How does a man determine what size hat he wears?
Last Answer : To measure the size of a person's head, use a flexible tape measure
Description : Platelets have a wide array of functions in inflammation. Which of the following are among these? a. Synthesis and release of vasoactive eicosanoids b. Release of chemotactic factors c. ... coating of bacterial and tumor cells d. Increase of vascular permeability e. Phagocytosis of bacteria
Last Answer : Answer: a, b, c, d Platelets are anucleated cells derived from megakaryocytes in the bone marrow. Their central role in hemostasis is well known. Platelets possess a wide ... primitive precursor inflammatory cell. Platelets serve primarily as an amplifier or modulator of the inflammatory response
Description : Rotation of an rf-feed source to produce a conical scan pattern is identified by what term?
Last Answer : Nutation.
Description : What pattern would be formed if sawdust was sprinkled on the glass instead of iron filings?
Last Answer : No specific pattern, sawdust is a nonmagnetic material.
Description : What is the radiation pattern of a quarter-wave antenna?
Last Answer : A circular radiation pattern in the horizontal plane, or same as a half wave.
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 : . If a basic half-wave antenna is mounted vertically, what type of radiation pattern will be produced?
Last Answer : Nondirectional.