awp [uandistar.org]

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AWPJNTU ONLINE EXAMINATIONS [Mid 1 -AWP]1. Indicate which of the following reasons for using a counterpoise with antennas is false[01D01]a. impossibility of a good ground connectionb. protection of personnel working underneathc. provision of an earth for the antennad. rockiness of the ground itself2. If an antenna is at a height h, above the earth (radius R ) simple geometry gives line- of -sight dustance (d) to the holizen [01D02]a. d=2Rhb.c.d.3. In case of the wire antennas the aerodynamic cinsiderations limit the angle between afixed wire and the air stream to about. [01D03]a. 100

b. 150

c. 300

d. 450

4. Current distribution on a resonant of length of 3/2 λ [01D04]a. Shown in figure(a)Figure(a)b. Shown in figure(a)Figure(a)c. Shown in figure(a)Figure(a)d. Shown in figure(a)Figure(a)5. Current distribution on a resonant dipole of length of λ [01D05]a. Shown in figure(a)Figure(a)b. Shown in figure(a)Figure(a)c. Shown in figure(a)Figure(a)d. Shown in figure(a)Figure(a)6. Current distribution on a resonant dipole of length of [01D06]a. Shown in figure(a)Figure(a)b. Shown in figure(a)Figure(a)c. Shown in figure(a)Figure(a)d. Shown in figure(a)Figure(a)7. Indicate which one of the following reasons for the use of an earth mat with antennas isfalse [01M01]a. impossibility of a good ground connectionb. protection of personnel working underneathc. provision of an earth for the antennad. improvement of the radiation pattern of the antenna8. Low frequency parallel-wire transmission lines does not radiate because [01M02]a. the distance between two wires is very large compared to wavelengthb. there is mismatch between wires and surrounding spacec. the electromagnetic energy is dissipated in the surrounding spaced. the radiation from one tip will cancel that from the other9. The field surrounds any current carrying wire is [01M03]a. induction fieldb. radiation fieldc. no field presentd. combination of both induction and radiation fields10. An antenna is used to convert [01S01]a. low frequency current into electromagnetic wavesb. high frequency current into magnetic wavesc. high frequency current into electromagnetic waves


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d. high frequency current into electric waveswww.UandiSTAR.org11. Transmitting and receiving antennas behave [01S02]a. identicallyb. differentlyc. equal in physical lengthd. cannot determine12. To increase the radiation from the transmission line [01S03]a. decrease the distance between the wiresb. open circuit at the end of line is enlargedc. short circuit at the end of lined. connect the matched load at the end of line13. A dipole is same as [01S04]a. the two wires bent so as to be in same lineb. the two wires connected with matched loadc. the two wires shorted at the endd. the two wires bent so as to form circle14. The total length of two wires is a half-wavelength , then the antenna is called a [01S05]a. two wire lineb. opened-out transmission linec. half-wave dipoled. full wave dipole15. The voltage and current along the antenna are [01S06]a. fixed to certain valueb. vary from one point to the nextc. constant along the lengthd. equal to unity16. Antennas made of wire whose diameter compared to wavelength is [01S07]a. largeb. infinitely smallc. twiced. independent of wavelength17. For most antenns, the outer boundary of Reactive near field region is commonly taken toexist at a diatance R isHere D is the largest dimension of the antenna λ is the wavelength [02D01]a.b.c.d. Independent of D and λ ; ;18. Fresnel region does not exit if antenna has a [02D02]a. Maximum dimension smaller than the wavelengthb. Maximum dimension larger than the wavelengthc. Minimum dimension smaller than the wavelengthd. Minimum dimension larger than the wavelength19. In which region the angular field distribution is dependent upon the distance from theantenn. [02M01]a. Reactive near field regionb. Radiating near field regionc. Far field regiond. Farunhofer region20. In which region the angular field distribution is independent of the distance from theantenna [02M02]a. Reactive near- field regionb. Radiating near - field regionc. Frerrul regiond. Far- field region21. The near zone fields of an oscillating time varying dipole are [02M03]a. dynamicb. staticc. quasii-staticd. constant22. In a plane containing an isolated hertizian dipole the radiation pattern of the antenna is a[02M04]a. Circle and the radiation is circular polarizedb. Circle and the radiation is linearly polarizedc. Figure of eight and the radiation is circularly polarizedd. Figure of eight and the radiation is linealy polarized23. Which of a minor lobe that occupies the hemisphere in a direction opposite to that of themajor lobe [02M05]


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a. Side lobeb. Main lobewww.UandiSTAR.orgc. Opposite lobed. Back lobe24. The ratio of the power radiated by the antenna to the square of the current at the feedpoint is [02S01]a. antenna lossesb. radiation intensityc. radiation resistanced. antenna resistance25. The radiation resistance of antenna is a [02S02]a. dc resistanceb. ac resistancec. combination of ac and de resistanced. loss resistance26. The induction and radiation fields of an oscillating dipole becomes approximately equal ata distance of r when r= [02S03]a.b.c.d.27. The boundary between the near field and far field may be arbitorarily taken to be at aradius R which is related to the wavelength, λ and maximum direction L(in meters) of theantenna as, [02S04]a.b.c.d. 2 λ /L2

28. The radiation lobe containing the direction of maximum radiation is called [02S05]a. side lobeb. back lobec. mirror lobed. major lobe29. A radiation lobe in any direction other than the intended lobe [02S06]a. back lobeb. major lobec. side lobed. main lobe30. A radiation lobe whose axis makes an angle of apporoximately 1800 with respect to thebeam of an antenna [02S07]a. Major lobeb. Minor lobec. Back lobed. Main lobe31. The largest lobe minor lobes is called [02S08]a. Major lobeb. Side lobec. Back lobed. Main lobe32. Generally the horizontally polarized antennas are preferred at high frequencies becausemost of man made noise is [03D01]a. vertically polarizedb. horizontally polarizedc. linearly polarizedd. circularly polarized33. In relation to the directional characteristics of the dipole antennas the terms θ and Opolaization are synonymous with and may be used for the following terms in that order[03D02]a. Horizantal and vertical polalizationb. Vertical and Horizantal polalizationc. Circular and elliptical polalizationd. Elliptic and circular polarization34. Antenna radiation efficiency is defined asec is conduction efficiencyed is dielectic efficiency [03M01]a.


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b.c.www.UandiSTAR.orgd.35. Beam efficiency of an antenna is defined as=power transmitted within core angle θ 1

PT=power transmitted by the antenna [03M02]a.b.c.d.36. A very high beam efficiency generally in the older of [03M03]a. > 90b. < 90c. < 10d. < 5037. A 10:1 band with of an antenna indicates that [03M04]a. The lower frequency is 10 times grater than the upper frequencyb. The gain of antenna is 10 times grater than the standard antennac. The upper frequency is 10 times grater than the lower frequencyd. The center frequency is 10 times greater than operating frequency38. The beam width of an antenna is the [03S01]a. frequency separation between the two half power pointsb. angular separation between the two half power pointsc. amplitude separation between the two half power pointsd. directive gain between the two half power points39. The beam soild angle is approximately equal to the product of the half power beamwidthsin [03S02]a. two parallel planesb. two perpendicular planesc. two linear planesd. one parallel plane and another perpendicular plane.40. The total efficiency eo can be written interms of reflection efficiency er, conductionefficiency ec and dielectic efficiency ed as [03S03]a.b.c.d.41. Beam efficiency of an antenna will indicate [03S04]a. The amount of power in the side lobe compared to the major lobeb. The amount of power in the minor lobe compared to the total powerc. The amount of power in the back lobe compared to the total powerd. The amount of power in the major lobe compared to the total power42. The radiation efficiency inturms of radiation resistance Rr and conduction- dielectic loss RL

detined as [03S05]a.b.c.d.43. Radiation intensity is defined as [03S06]a. The power radiated from an antenna per unit solid angleb. The power radiated from an antenna per unit area.c. The power loss from an antennad. The total power applied to an antenna.44. Radiation intensity is express as- radiation density w/m2

R= distance [03S07]a.b.c.d.45. Radiation intensity of an antenna is [03S08]a. near field parameterb. far field parameterc. oscillating field parameterd. Reactive field parameter46. The relative gain of a glass- mounted antenna in comparison to the roof- mountedantenna is [04D01]


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a. Less by 3dBb. Less by 5dBc. Mole by 3dBwww.UandiSTAR.orgd. Mole by 6dB47. The directive gain of all practical antennas is [04M01]a. greater than unityb. less than unityc. Zerod. equal to unity48. The power gain and directivity both are same except that power gain takes into accountthe [04M02]a. antenna resistanceb. antenna lossesc. antenna aread. maximum intensity49. The standard reference antenna for the directive gain is the [04S01]a. infinitesimal dipoleb. isotropic antennac. elementary doubletd. half wave dipole50. The ratio of the power density radiated in that direction by the antenna to the powerdensity that would be radiated by an isotropic antenna [04S02]a. power gainb. radiation resistancec. directive gaind. radiation intensity51. The directive gain of an antenna is increased with [04S03]a. decreased lengthb. decreased radiation intensityc. increased lengthd. increased radiation resistance52. The maximum value of directive gain is called [04S04]a. power gainb. resistivityc. directivityd. maximum intensity53. The relation between power gain P and directivity D isη antenna efficiency [04S05]a. A = η Db. A = 1/η Dc. D = η Ad. A = η /D54. The directivity in terms of half power beamwidths is=half power beamwidth in one plane(radians) =half power beamwidth in a planerightangle to the other. [04S06]a.b.c.d.55. The maximum directivity of an antenna is expressed as=maximum rediation intensity =total radiation power [04S07]a.b.c.d.56. The directivity of an istropic source is [04S08]a. infinityb.c. zerod. unity57. The propagation velocity within the antenna is [05D01]a. more than in free spaceb. less than in free spacec. equal to free spaced. not related to free space58. MF broad casting transmitting antennas are generally vertical rediatoes with heightranging between [05D02]


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a.b.c.www.UandiSTAR.orgd.59. Top loading is sometimes used with an antenna in order to increase its [05S01]a. effective heightb. bandwidthc. beam widthd. input capacitance60. The antenna efficiency is defined as [05S02]a.b.c.d.61. An ungrounded antenna near the ground. [05S03]a. acts as a single antenna of twice the heightb. is unlike to need a ground screenc. act as an antenna arrayd. must be horizantally polarized62. The effictive length ell e of an antenna is expressed asEi= incident electric field=open circuit voltage at antenna terminals [05S04]a.b.c.d.63. The maximum effective length of an element with an ideal uniform current distribution is[05S05]a. equal to its physical lengthb. square of its physical lengthc. half of is physical lengthd. Independent of its physical length.64. The ratio of the avaliable power at the terminals of a receiving antenna to the power fluxdensity of a wave incident on the antenna is called [05S06]a. Effictive Lengthb. Gain of Antennac. Effective Aread. Directivity65. Scattering area is expressed aswi= power density of incident waveVT=induced voltage when wave impinges upon the antennaRr= rediation resistance.RL= loss resistance. [05S07]a.b.c.d.66. Capture area of antenna is sum of [05S08]a. Effective and loss areab. Scattering and loss areac. Effective and scattering aread. Effective, Scattering and loss area67. Aperture efficiency of an antenna is defined as [05S09]a. The ratio of maximum effiective area of antenna to its physical area.b. The ratio of capture area of antenna to its physical areac. The ratio of scattring area of antenna to its physical aread. The ratio of loss area of antenna to its physical area68. The strength of the radiated field from short dipole isd = distance of the point at which the field strength is measured from the elementarydoublet= is velocity of light in free spaceθ = angle of inclination [06D01]a.b.c.d.69. For a very short dipole or equivalent radiator, the outer foundary is commonaly taken to


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exit at a distance [06D02]a. from the antenna surfaceb. from the antenna surfacewww.UandiSTAR.orgc. from the antenna surfaced. from the antenna surface70. The radiation from the elementary dipole is [06S01]a. minimum at right angles to the dipoleb. maximum at in line with the dipolec. maximum at right angles to the dipoled. same in all directions71. The radiation pattern of half wave dipole is like that of the [06S02]a. circleb. elementary doubletc. elementary sphered. single lobe72. A direction of maximum radiation for a full wave dipole is at [06S03]a. 900

b. 00

c. 250

d. 540

73. The radiation pattren for resonant dipole of length [06S04]a. Shown in figure(a)Figure(a)b. Shown in figure(a)Figure(a)c. Shown in figure(a)Figure(a)d. Shown in figure(a)Figure(a)74. The radiation pattren for resonant dipole of length λ is [06S05]a. Shown in figure(a)Figure(a)b. Shown in figure(a)Figure(a)c. Shown in figure(a)Figure(a)d. Shown in figure(a)Figure(a)75. The radiation pattren for resonant dipole of length is [06S06]a. Shown in figure(a)Figure(a)b. Shown in figure(a)Figure(a)c. Shown in figure(a)Figure(a)d. Shown in figure(a)Figure(a)76. The radiation pattren for resonant dipole of length is [06S07]a. Shown in figure (a)Figure(a)b. Shown in figure (a)Figure(a)c. Shown in figure (a)Figure(a)d. Shown in figure (a)Figure(a)77. The H- field component present in the radiation fields of an infinitesimal dipole is [06S08]a. Hr

b.c.d.78. The reactance of an infiniterimal dipole is always [06S09]a. inductive


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b. resistivec. complexd. Capacitive79. The E field radiated by a small dipole in the far field region can be expressed asη= intensic impedancewww.UandiSTAR.orgk= propagation constantr= radial distanceIo= constant currentl= length of antenna [07D01]a.b.c.d.80. The time average power in near field region is [07M01]a. infinityb.c. zerod.81. The field components of infinitesimal dipole in far- field region form a [07M02]a. Transvrese electic waveb. Transvrese magnetic wavec. Transvrese electiomagnetic waved. standing wave82. The H field riadiated by a small dipole in far field region can be expressed ask=propagation constantr=radial distanceIo= uniform constant currentl=length of antenna [07M03]a.b.c.d.83. At intermediate distance, the an Er of electic dipole approach time phase quadrature sothe total electric field exhibiting the phenomenon of [07M04]a. Electric fieldb. Magntic fieldc. Cross fieldd. No field84. If the ground is good conductor, it converts grounded dipole into [07S01]a. a dipole of twice the heightb. two dipole arrayc. not effect on itd. dipole of same height85. If the ground is good conductor, it converts grounded dipole into [07S02]a. a dipole of twice the heightb. two dipole arrayc. not effect on itd. dipole of same height86. The power radited by an antenna can find by using [07S03]a. poynting vectorb. compiex vectorc. vector potentiald. complex input impedcuce87. The E field radiated by a small dipole in the far field region is [07S04]a.b. Er

c.d.88. The H field radiated by a small dipole in the far field region is [07S05]a. Hr

b.c.d.89. The directive gain of a eight wave dipole is [08D01]a. 1.64b. 1.5


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c. 7.1d. 1.090. The directivity of a monopole is [08D02]a. 1.5b. 1.64c. 3.00d. 3.28www.UandiSTAR.org91. The directivity of a short monopole is [08D03]a. 1.5b. 1.64c. 3.00d. 3.2892. Find the radiation resistance of an infinitesimal dipole whose overall length is l=[08M01]a. 30 Π 2

b. 73 ohmsc. 36 ohmsd. 0.316 ohms93. The 3-dB beam width of a dipole of length is [08M02]a. 870

b. 640

c. 780

d. 47.80

94. The 3-dB beam width of a dipole of length is [08M03]a. 870

b. 640

c. 780

d. 47.80

95. The 3-dB beam width of a monopole antenna is [08M04]a. 870

b. 640

c. 780

d. 47.80

96. The directive gain of a half wave dipole is [08S01]a. 1.64b. 1.5c. 1.0d. 1.7597. For a lossless antenna the real oart of the input impedance was designated as [08S02]a. Lossless resistanceb. Radiation resistancec. Lossless inductanced. Radiation inductance98. The radiation resistance of an infiniterimal dipolies [08S03]a.b.c.d.99. The vertical radiator taller than about 0.53 λ is not used in ground wave propagationbecause [09D01]a. their presence will cause high radiationb. they have high directivityc. their presence will cause high radiation resistanced. their presence will cause quite objectionable sky wave interference100.The actual height should be at least a [09M01]a.b.c.d.101.An antenna much shorter than has a [09M02]


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a. high resistanceb. low capacitive reactancec. poor input impedanced. efficient radiator102.The input impedance of a short dipole with length nearer to 0.23 λ contains a reactancewhich is normally [09M03]a. Large & capacitiveb. Small and capacitivewww.UandiSTAR.orgc. Large & inductived. Small and inductive103.The input impedance of a dipole antenna having tip- to-tip physical length equal to halfwave length is [09M04]a. Pure resistanceb. Pure capacitancec. Inductior impedanced. Capacioture impedance104.The top loading of antennas [09S01]a. decreases radiation resistanceb. increases radiation resistancec. increases capacitive reactanced. poor input impedance105.The effective area of a very short lossless dipole is [09S02]a. 0.13 λb. 0.119 λc. 0.119 λ 2

d. 0.13 λ 2

106.The current distribution along the length of a small dipole ( ) is [09S03]a. uniformb. sinusoidalc. rectangulard. exponential107.The current distribution along the length of linear antenna is [09S04]a. uniformb. sinusoidalc. rectangled. constant108.The impedance of half wave dipole antenna and radiating into an unbounded idealdielectic medium is [10D01]a. a pure resistanceb. a pure capacitancec. an impedance with capacitive reactanced. an impedance with inducture reactance109.If Z is the input impedance of a simple dipole, the impedance of n fold dipole is [10D02]a. n zb. n2zc. z/nd. z/n2

110.The far field of a symatrical, center- fed thin linear antenna of length L is [10D03]a.b.c.d.111.The radiation resistance ` R1 ` at a point which is not a current maximum isRo= radiation resistance x=distanceβ=propagation constant [10D04]a.b.c.d.112.The point at which a particular antenna is fed is determined by [10M01]a. directivityb. radiation intensityc. antenna impedanced. antenna efficiency


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113.A center fed full wave antenna is said to be [10M02]a. voltage fedb. current fedc. low impedance feedd. mixed fed114.A center fed half wave antenna is said to be [10M03]a. voltage fedb. current fedc. high impedance feedd. mixed fedwww.UandiSTAR.org115.A straight dipole radiator fed in the center will cause maximum radiation [10M04]a. In the plane parallel to its axisb. In the plane normal to its axisc. At the place of feedd. At its extreme ends116.A dipole antenna fed at the extrem left and will produce a beam, which will be [10M05]a. tilted towards leftb. tilted toward rightc. perpendicular to the dipoled. parallel to the dipole117.The patern factor of a symmetrical, center fed thin linear antenna of length L= is[10M06]a.b.c.d.118.The restriction for reciprocity to hold for the antennas in the transmit and receive modesare [11M01]a. matched feed linesb. same shapec. polarization matchedd. same size119.The transmitting antenna is circularly polarized and the probe antenna is linearlypolarized but used twice and it is oriented one time to measure the θ component and theother O component then the radiation pattern in both termitting and receiving modes is[11M02]a. sameb. differentc. opposite phased. the patteren in receiving mode is twice that of transmitting mode120.The receiving mode of opeaction for the test antenna is most widely used to measureradiation patteren to verify reciprocity theorem because [11M03]a. The receiving equipment is more accurateb. The receiving equipment as small and light weightc. The transmitting equipment small and light weightd. The transmitting equipment is not accurate121.Under condition of reciprocity, the power delivered in either direction (transmitting orreceiving)is [11S01]a. sameb. oppositec. 900 out of phased. 1800 out of phase122.The radiation pattern of an antenna is same for both transmitting and receiving modeunder the condition [11S02]a. Superpositionb. Reciprocityc. Dualityd. Equality123.The reciprocity principle is valid for the media of [11S03]a. nonlinear, passive and isotropicb. linear, passive and non-isotropicc. nonlinear, passive and non-isotropicd. linear, passive and isotropic124.To hold a reciprocity principle , the emfs in the terminals of the interchanged antenns areof the [11S04]a. same amplitude


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b. same frequencyc. outof phased. equal phase125.The reciprocity therom for antennas states that [11S05]a.b.c.d.126.An emf Va be applied to the terminals of antenna A and an emf Vb applied to the terminalsof antinna, if then by reciprocity theorem [11S06]a.www.UandiSTAR.orgb.c.d.127.The effective length of antenna either in transmitting or receiving mode is sameaccording to the theroem of [11S07]a. Equiprincipleb. Superpositionc. Mximum powerd. Reciprocity128.Identify the incorrect statement [12D01]a. Dipole antennas are balanced antennas if fed by two conductor transmission line.b. Dipole antennas are un-balanced antennas if fed by two conductor transmission linec. Dipole antennas are narrowest bandwidth antenna.d. Short dipole has the same directivity as that of a small loop.129.The radiation resistance of a circular loop with number of turns and diameter D is[12D02]a. 19000N(D/ λ)4

b.c.d.130.The loop antenna is suitable for direction finding because the radiation pattern is[12M01]a. no radiation is received in normal to the plane of the loopb. radiation is received in normal to the plane of the loopc. no radiation is received in the plane of the loopd. spherical distribution around the loop131.The directivity of the small loop and sholt dipole has the following ratio [12M02]a. 1:2b. 2:1c. 1:1d. 1:4132.The maximum radiation is directed toward the axis of loop forming [12M03]a. An end-fire antennab. Broad side antennac. A binomial arrayd. Scanned array133.To achive maximum radiation towards the axis of loop,the circumference of the loopshould be about [12M04]a. half of a free space wavelengthb. twice that of a free space wavelengthc. equal to one free space wavelengthd. square root of one free space wavelength134.The current throughout loop antenna may be assumed [12S01]a. out of phaseb. in phasec. zerod. infinity135.Electrically large loops are those whose circumference is about [12S02]a.b.c.d.136.Loop antenns with electcally small circumferences preferred only for receiving modebecause [12S03]a. they are very poor radiatoursb. loss resistance is more


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c. loss resistance is smalld. small in size137.The magnetic field components present due to a small circular loop are [12S04]a.b.c.d.138.The electic field components present due to small circular loop is/are [12S05]a.b.c. Er

d.www.UandiSTAR.org139.To qually as a small loop their dimensions should be [12S06]a.b.c.d.140.A magnetic dipole of magnetic moment is equivalent toa= radius of small loop =constant electric current [13D01]a.b.c.d.141.The radiation resistance of a single turn loop is [13D02]a. 31,171b. 31,171c. 31d. 31,171142.The total ohmic resistance for an `N` turn circular loop antenna with loop radius `a`wire radius 'b' isRs Surface impedance of conductorRp ohmic resistance per unit length due to proximity effectRo ohmic skin effect resistance per unit length. [13D03]a.b.c.d.143.A ferrite core of very high permeability is inserted in a loop to [13M01]a. Decrase radiation resistanceb. Decrease the magnetic field intensityc. Increse radiation resistanced. Increse its perimeter144.The radiation resistance of a single burn loop is 0.788 ohms, find radiation resistance of8-turns circular loop? [13M02]a. 1.576 ohmsb. 0.788 ohmsc. 50.43 ohmsd. 100.86 ohns145.The directivity of a small loop is [13M03]a. twice that of an infinitisimal electic dipoleb. twice that of an infinitisimal magnetic dipolec. same as that of an infinitisimal electic dipoled. half that of an infinitisimal magnetic dipole146.A small loop is equavalent to [13S01]a. an in finitesimal electric dipoleb. an infinitisimal magnetic dipolec. a array of small infinitisimal electic dipoled. a array of small halfwave dipole147.The radiation resistance of the loop can be increase by (indicate balse one) [13S02]a. Decreasing its perimeterb. Increasing no of turnsc. Increasing its perimeterd. Inserting ferrite rod148.The loss resistance of single turn loop is [13S03]a. equal to radiation resistanceb. less than radiation resistance


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c. grater than radiation resistanced. equal to input resistance149.The directivity of the loop is [13S04]a. 3/2b. 5/2c. 4/3d. 1/2150.The maximum effective aperture of the loop is [13S05]a.b.c.d.151.The elements in an antenna array are placed [14D01]www.UandiSTAR.orga. within each others induction fieldb. within radiation fieldc. within oscillating fieldd. away from each other152.An ungrounded antenna near the ground [14M01]a. acts a an single antenna of twice the heightb. is unlikely to need an earth matc. acts as an antenna arrayd. must be horizontally polarized153.The director behaves like a [14M02]a. concave lensb. convex mirrorc. convex lensd. mixed lens154.one of the following is very useful as multi-band HF receiving antenna [14M03]a. Half-wave dipoleb. Quarter wave momo-polec. Two- element arrayd. Log periodic antenna155.The radiation pattern of the an antenna array is the [14S01]a. scalar sum of the individual onesb. vector sum of the individual onesc. vector multiplication of the individual onesd. sum of phases of the individual ones156.An element in an array directly connected to the transmitter is called [14S02]a. parasitic elementb. directorc. driven elementd. reflector157.An element in an array not directly connected to the transmitter is called [14S03]a. parasitic elementb. source elementc. driven elementd. sink element158.A parasitic radiator receives energy through the [14S04]a. radiation field of driven elementb. induction field of driven elementc. radiation field of directord. induction field of director159.The parasitic element longer than driven element is called [14S05]a. reflectorb. directorc. driven elementd. radiator160.The parasitic element shorter than driven element is called [14S06]a. reflectorb. directorc. driven elementd. radiator161.A parasitic element shorter than driven element increase radiation in its [14S07]a. own directionb. opposite directionc. direction of reflectord. opposite direction of driven element162.A parasitic element longer than driven element increase radiation in its [14S08]a. own direction


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b. opposite directionc. direction of reflectord. opposite direction of driven element163.The init pattern of the following will be a figure of eight shape [14S09]a. two elements with λ spacingb. two elements with spacingc. two elements withd. two elements with spacing164.Side lobes is a broad side array will be entirely eliminated provided the spacing betweenadiacent antennas doesnot euceed [15G01]a.b. λwww.UandiSTAR.orgc.d.165.The directional pattern of an end fire array using isotropic radiators is substantiallyindependent of the spacing of the antenna radiators provided this spacing doesnot exceed[15G02]a.b.c.d.166.The elements of array are placed equally spaced and fed in same phase from samesource than the array is called [15S01]a. broadside arrayb. end fire arrayc. binomial arrayd. two element array167.The elements of array are placed equally spaced and fed in uniform phase differencefrom same source than the array is called [15S02]a. broadside arrayb. end fire arrayc. binomial arrayd. two element array168.The radiation pattern of broadside array is in the direction of [15S03]a. along the plane of arrayb. perpendicular to the arrayc. uniform radiationd. circle in shape169.The radiation pattern of end-fire array is in the direction of [15S04]a. along the plane of arrayb. perpendicular to the arrayc. uniform radiationd. circle in shape170.The end-fire array is [15S05]a. linear and non resonantb. non linear and resonantc. linear and resonantd. non linear and non resonant171.The broadside array is [15S06]a. linear and non resonantb. non linear and resonantc. linear and resonantd. non linear and non resonant172.The broadside array is used for [15S07]a. only for single frequency receptionb. only for multiple frequency transmissionc. only for multiple frequency receptiond. only for single frequency transmission173.The end-fire array is used for [15S08]a. only for single frequency receptionb. only for multiple frequency transmissionc. only for multiple frequency receptiond. only for single frequency transmission174.The broadside array is used only for single frequency transmission because [15S09]a. have a single frequency operationb. have a narrow bandwidthc. have a broad bandwidth


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d. have a multiple frequency operation175.The end-fire array is used only for single frequency transmission because [15S10]a. have a single frequency operationb. have a narrow bandwidthc. have a broad bandwidthd. have a multiple frequency operation176.Generally broad side array is not suitable for reception because it [15S11]a. have a single frequency operationb. have a narrow bandwidthc. have a broad bandwidthd. have a multiple frequency operation177.Generally end-fire array is not suitable for reception because it [15S12]a. have a single frequency operationb. have a narrow bandwidthwww.UandiSTAR.orgc. have a broad bandwidthd. have a multiple frequency operation178.An array consisting of a number of dipoles of equal size, equally spaced along a straightline, with all dipoles fed in the same phase from the same source is called [15S13]a. End-fire arrayb. Back fire arrayc. Broad side arrayd. Binomial array179.When the current ratios and phasings are properly chosen sharp directivity with an arrayof fixed length but sufficiently large number of elements can be obtained with thisphasing and close spacings between elements the radiation resistance [16D01]a. Reduces to very low valueb. Increases to very high valuec. Remains unaffectedd. Changes only slightly180.If the distribution of amplitude of element excitation of a center- symmetric linear arraywith is such that the farther the element from the center the lower is excitation,than compared to the uniformly excited array, the radiation pattern of such a gradedarray will have [16D02]a. wide beam widthb. narrow beam widthc. almost the same beam widthd. beam related with grading function181.At 450 MHz the half power beam width of a 3- element array is [16M01]a. 80

b. 100

c. 120

d. 280

182.At 450 MHz the half power beam width of a 7- element array is [16M02]a. 100

b. 120

c. 80

d. 280

183.The sidelobe less broadside arrays are called [16M03]a. Uniform arrayb. End-fire arrayc. Log periodic arrayd. Binomial array184.The width of the major lobe is almost- exact inversely proportional to the array length if[16M04]a.b.c.d.185.At the operating wavelength λ the active region of a log periodic dipole array consistsmainly of several dipoles whose lenghs approximately equal to [16M05]a.b. λc.d. several λ


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186.To obtainted the maximum radiation in any direction the required array is [16M06]a. Broad side arrayb. End fire arrayc. Binomial arrayd. Scanning array187.To accomplish the maximum radiation of the scanning array at an angkle , the requiredphase excitation β between the elements must be adjusted so that [16M07]a.b.c.d.188.An array consisting a number of radiators equally spaced along a line and carryingcurrent of the same phase, shell mainly radiate [16S01]a. in a plane parallel to the line of arrayb. in a plane perpendicular to the line of arraywww.UandiSTAR.orgc. at 300 angle from the line of arrayd. at 600 angle from the line of array189.The following antenna- array has no side lobes [16S02]a. End-fire arrayb. Back - fire arrayc. Broad side arrayd. Binomial array190.The relative amplitudes of the elements in binomial array can be determined by [16S03]a. Polynomial expansionb. Sinusoidal expansionc. Binomial series expansiond. TSChebyscheff expansion191.The length of the resonant antenna is increased, the number of lobes must be [17M01]a. decreasedb. increasedc. single lobed. independent of length192.Indicate the false statement with respect to non resonant antenna [17M02]a. matched termination is usedb. only a forward traveling wave will existc. two-thirds of the forward power is radiatedd. there are standing waves193.Resonant length antennas cannot be used at a frequencies of [17M03]a. HFb. UHFc. low and mediumd. VHF194.The effective length of the antenna is resonant then the impedance at its center will be[17M04]a. purely inductiveb. purely capacitivec. purely resistived. complex195.The tilt angle of the travelling wave antenna is increased then phase velocity & beamwidth are [17M05]a. increased and reducedb. reduced and increasedc. both are increasedd. both are reduced196.One of the following consists of non resonant antennas [17S01]a. rhombic antennab. folded dipolec. end-fire arrayd. broadside array197.The directive gain of non resonant antennas compared to resonant antennas of equallength [17S02]a. lessb. equalc. mored. un compared198.The length of the resonant antenna is increased, the number of lobes must be [17S03]a. decreased


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b. increasedc. single lobed. independent of length199.Identify the correct answer [17S04]a. only length is the resonant lengthb. only length λ is the resonant lengthc. both and λ are the resonant lengthd. only length is the resonant length200.A single wire antenna terminated in its characteristic impedance have a [17S05]a. Uniform travelling waveb. Standing wavec. No propagationd. Exponentially decreased201.The phase velocity of the travelling wave on the antenna is reduced, the beam width[17S06]www.UandiSTAR.orga. Increasedb. Decreasedc. Remain constantd. Not related to phase velocity202.There are four antenna configurations1) a simple dipole2) a flet sheet placed in front of simple dipole3) a flat sheet placed in front of two dipoles4) a flat sheet folded into a 900 square corner and is placed in front of simple dipole.The directivities of the above for configurations will be in the order of [18D01]a. 1.64 : 3:6:9b. 1.64:4:8:12c. 1.64:5:10:15d. 1.64:5:10:20203.The total field radiated by the long wire in the presence of the ground can be found byR0= The field radiated by the wire in free spaceAf= array factor of two element array [18D02]a.b.c.d. R0

204.Which of the following antenna is called Beverage antenna [18D03]a. Dipoleb. Loopc. Rhombicd. Long wire205.The radiation pattern of long wire antenna is [18M01]a. Single major lobeb. Figure of eightc. Sphericald. Multilobe pattern206.As the length of long wire antenna increases then the angle of the maximum ofthe major lobe approaches zero degrees then the structure becomes a [18M02]a. near end fire arrayb. near broadside arrayc. binomial arrayd. scanned array207.The radiation patterns for travelling and standing wave long wire antennas respectively[18M03]a. Un directional and Bidirectionalb. Bidirectional and unidirectionalc. Both area in unidirectionald. Both are in Bidirectional208.A long wire antenna is mostly used for receiving than transmitting because of its[18M04]a. Poor radiation efficiencyb. High gainc. Good sensiturtyd. Low radiation resistance209.As the wave travels along the long wire from the source toward the load, it continuosly


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[18S01]a. radiates energyb. leaks energyc. Amplifies energyd. remains constant210.An antenna is useually classified as a long wire antenna if it is a straight conductor witha length ` ` of [18S02]a.b.c.d.211.When the radiating medium is air, the loss of energy in a long wire due to leakage is[18S03]a. Largeb. Does not dependent on mediumc. Small and negligibled. Small and not negligible212.A long wire antenna is [18S04]www.UandiSTAR.orga. Circullary polarizedb. Linearly polarizedc. Elliptically polarizedd. Spherically polarized213.In a Rhombic antenna the angle of elevation of the main beam is contained mainly by[19M01]a. Height of antenna above the groundb. Length of the side wires forming the rhombicc. Tilt angled. The terminating resistance214.The input and terminating impedance in a rhombic antenna are usually about equal andof the order of [19M02]a. 150-200 ohmsb. 200-400 ohmsc. 300-600 ohmsd. 600-800 ohms215.The reflected waves can be reduced by making the inclined wires of the V- antennarelatively [19M03]a. Thickb. Thinc. shortd. Long216.The angle of inclination of radiation of V antenna is determined by [19M04]a. angle between two wiresb. open impedancec. length of each wired. characteristic impedance217.Rhombic antennas are usevally prefferred over V antennas because [19M05]a. more directiveb. lower side lobesc. easy to terminated. easy to form arrays218.The radiation pattern of rhombic antenna is [19S01]a. bidirectionalb. unidirectionalc. sphericald. uniform219.The rhombic antenna is [19S02]a. resonantb. non resonantc. isotropicd. array220.The rhombic antenna is used at high frequencies [19S03]a. only for transmissionb. only for receptionc. for both transmission and receptiond. it is not used at high frequencies221.The rhombic antenna is used for both transmission and reception because [19S04]a. have a single frequency operationb. have a narrow bandwidth


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c. have a broad bandwidthd. have a bidirectional pattern222.To get a maximum directivity in a longer V antennas the included angles becomes[19S05]a. Largerb. Smallerc. Doesnot dependentd. Constant223.To acheive the unidirectional characteristics, the wire of the V antenna must be [19S06]a. Resonantb. Non resonantc. Seriesd. Parallel224.The pitch angle `α of the helix antenna is defined by [20D01]a.b.c.d.225.In the normal mode the helix consists of (N turns) [20D02]a. N small loopswww.UandiSTAR.orgb. N short dipolec. N small loops and N short dipoles connected together in seriesd. N small loop and N short dipoles connected together in parallel226.A helical antenna is used for satellite tracing because of its [20M01]a. circular polarizationb. maneuverabilityc. broad bandwidthd. good front-to-back ratio227.If the circumference of helix of helical antenna is very small compared to a wavelengththen the radiation is [20M02]a. a combination of small dipole and a small loopb. only due to a small dipolec. only due to a small loopd. equal to a wire228.When a mono- filar helical antenna is operated in normal mode, the maximum radiationoccurs in the plane [20M03]a. parallel to the helix axisb. perpendicular to the helix axisc. located at450 to the helix axisd. artritiarily located in respect to the helix axis229.The ground plane of the helical antenna should be atleast [20M04]a.b.c. λd.230.The axial ratio AR= =1 in helical antenna operating in normal mode, the radiated fieldis [20M05]a. linearly polarized wave of horizantal polarizationb. linearly polarized wave of vertical polauizationc. circularly polorizedd. elliptically polarized231.The bandwidth of helical antenna in normal and axial mode corespondingly [20M06]a. narrow and greaterb. greater and narrowc. both greaterd. both narrow232.An antenna that is circularly polarized is the [20S01]a. helicalb. small circular loopc. rhombicd. V antenna233.Helical antenna is used at frequencies of [20S02]a. Low frequenciesb. high microwave frequenciesc. VHF and UHFd. Ku and Ka bands234.The circumference of helix in helical antenna is approximately [20S03]


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a.b.c.d. λ235.Helical antenna will accept the polarization of [20S04]a. only verticalb. only horizontalc. both vertical and horizontald. only circular236.Helical antenns are often used for satilite tacking at VHF range bacuase of [20S05]a. Troposcatterb. Super refractionc. Ionospheric refractiond. the faraday effect.237.The pitch angle alpha = 00 then the helix antenna reduces to a [20S06]a. linear wireb. dipolec. loopd. half wave dipole238.The pitch angle alpha = 900 then the helix antenna reduce to a [20S07]www.UandiSTAR.orga. linear wireb. dipolec. loopd. V- antenna

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