by which name is an ionospheric propagation, also known as

C. Maximum radiated power along main axis According to the geometry, how many sterdians are present in a full sphere? B. A. Sinusoidal In this region signals on some frequencies are attenuated much less than might normally be experienced and as a result signals can be received at surprisingly high levels over very long distances - even from the other side of the globe. Why are beverage antennas not used as transmitting antenna? The height of the layers follows alphabetical order. 43. B. B. A. B. Self impedance of an antenna is basically __________, A. Hey Engineers, welcome to the award-winning blog,Engineers Tutor. Only Refraction If an observation point is closely located to the source, then the field is termed as ________, A. The nature of the interaction of electromagnetic waves with the ionosphere depends strongly on the frequency of operation. Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to unity? C. Reflective region 40) By which name/s is an ionospheric propagation, also known as? 47. B. | Principles of Operating Systems, Temperature and pressure decrease as you go higher up the troposphere. A. 59. C. Both a & b By how many times is an input impedance of a folded dipole at resonance greater than that of an isolated dipole with same length as one of its sides? Our system of global communication depends on radio waves. In flared transmission line, the radiation phenomenon increases due to ________ in flaring, A. Frequencies in UHF range (TV signals) propagated by means of space waves. More Topics. 13. C. Plane angle C. Fraunhofer region If the path difference of two waves with single source traveling by different paths to arrive at the same point, is λ/2, what would be the phase difference between them? 60. 98. A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. B. Axial Ionospheric correction using NTCM driven by GPS Klobuchar coefficients for GNSS applications Initial Moderate 0.047 m2 Low Equal to Introduction This page is about the Ionosphere, how it was discovered, what it is, and what you can do with it. D. None of the above, Ans: Wave is incident normal to plane of the loop with no induced voltage. The Earth’s magnetic field has a major influence on the occurrence of scintillation and regions of the globe with similar scintillation char… Propagation means how radio waves travel from one point to another point on the earth through free-space. B. Rectangular A. D. Gyrator. C. Both a and b What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis? 84. D. Poisson’s. Which mechanism/s is/are likely to occur in mid-frequency operation corresponding to ionospheric region? 57. ionosphere and from there to the receiver on Earth is known as Sky Wave Propagation. C. Power Pattern ionospheric propagation. ANSWER: Reflection or Scattering. Which among the following is an application of high frequency? A. Here extreme ionization takes place. According to Secant law, which frequency is greater than critical frequency by a factor of secθi? 87. A dipole carries r.m.s. Due to this layer, all over the world can be reached via radio. Ground waves travel along the surface of the earth. What is /are the advantages of using ferrite loops? C. Capacitive Antenna and Wave Propagation Question and Answer. D. Invasion layer. 25. 16. Dipole antenna is symmetrical in nature where the two ends are at equal potentials with respect to _____point, A. Usually happens above 50 MHz, and unlike the ionosphere, it is weather-related. Linear Narrowest Increase in radiation resistance English-Chinese dictionary. 95. Therefore, the choice of the most convenient model of the resulting propagation phenomena also depends on the frequency. 1 m – 10 m 34. Wavefront is basically a locus of points acquiring similar _______, A. Copyright 2020 , Engineering Interview Questions.com, ANTENNA and WAVE PROPAGATION Objective Questions and Answers :-. D. Opposite. D. Square. 80. B. Voltage Pattern A. Permittivity C. Conformal B. The atoms take on or loose electrons – become positive or negative ions. Plane 35. D. None of the above. Reflection, refraction and diffraction may occur. What is the far-field position of an electric short dipole? 51. Field pattern estimation due to any length of antenna D. All of the above. Ultraviolet radiation interacts with the upper atmosphere to form an ionized layer known as the ionosphere. D. Metallic device for radiating or receiving radio waves, Ans: Metallic device for radiating or receiving radio waves. This makes received signals particularly strong at the skip distance. C. Array 44. All these EM Waves differ in frequency and wavelength. 94. D. Square. 7. B. EM waves are cobination of Electric and Magnetic waves. C. 0.5521 m2 Active region 40. This communication method is variable and unreliable, with reception over a given path depending on time of day or night, the seasons, weather, and the 11-year sunspot cycle. D. Wave equation. The F region is the most important part of the ionosphere in terms of HF communications. C. Angle inclination (Ψp) D. Front to back ratio (FBR), 17. Towards B. D. Facsimile, 3. Required fields are marked *, Without hardwork nothing grows except weeds. Ionosphere is the ionized layer around the Earth’s atmosphere, which is suitable for sky wave propagation. Which pattern is generated due to plotting of square of amplitude of an electric field? D. None of the above. Along with temperature rise sharp changes caused by the corpuscular and ultraviolet solar radiation are observed in it. B. Sky waves are reflections from the ionosphere also known as ionospheric propagation. D. Inductive. Exist only during day light hours. D. Diffracted. 46. a. B. Loop A. Widest From the radiation point of view, small loops are _________radiators. C. Radio navigation C. Defraction ANSWER: Sky wave propagation. Normal E-region The test instrument is sometimes also known as a vertical incidence sounder, VIS, and this name gives an indication of the operation of the ionosonde. What would happen if the rms value of induced emf in loop acquires an angle θ = 90°? Reflection or Scattering b. Refraction c. Defraction d. All of the above. Overlaps the other atmospheric layers from above the earth, Located within the thermosphere & height: Up to 350 Km. A. In radio communication link, what is the shape/nature of waves generated by transmitting antenna? B. Planer D. None of the above, Ans: Distance of point from the source (R). Hey Engineers, welcome to the award-winning blog,Engineers Tutor. Which type of ground wave travels over the earth surface by acquiring direct path through air from transmitting to receiving antennas? Low radiation efficiency A. Ionospheric 41. Due to the ability of ionized atmospheric gases to refract high frequency (HF, or shortwave) radio waves, the ionosphere can reflect radio waves directed into the sky back toward the Earth. A. Ions D. Both Ex & Ey & out of phase. 65. Note that space waves are also known as direct waves. D. Phase. 0.0475 m2 Amateur radio operators, also known as ham radio operators, are radio hobbyists who are licensed to conduct two‐way communications on amateur radio frequencies for noncommercial purposes. a. 45 km – 85 km In solution evaluation process of inhomogeneous vector potential wave equation, if points are completely removed from the source, then by which factor does the time varying field & static solution differ? Solved assignment problems in communicaion |online Request, Examples of Algorithms and Flow charts – with Java programs, What is Operating System? Definition: A type of radio wave communication in which the electromagnetic wave propagates due to the reflection mechanism of the ionospheric layer of the atmosphere is known as sky wave propagation. A. D. None of the above. What is the nature of current distribution over the small dipoles? * 1966: (ITSA1): Lucas and Haydon (ESSA Tech. The lowest layer D (at a height of 30 to 60 miles) is the ionospheric layer that is closest to the surface of the earth. C. Along z-axis C. Transducer between guided wave & free space wave C. Partial reflection & refraction For which band/s is the space wave propagation suitable over 30 MHz? Ionosphere has important quality of bouncing radio signals transmitted from the earth. Note that at frequencies beyond 3 MHz the earth begins to attenuate radio signals. C. Triangular According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value? It is also known as a line of sight propagation as the signals are sent in a straight line from the transmitter to the receiver. They can travel at distances beyond the horizon and are always vertically polarised. Plane to spherical wave First null beam width (FNBW) Space wave communication occurs when both antennas are within LoS (Line of Sight) of each other. 73. D. All of the above The ionospheric layers used for skywave propagation are layers D, E, and F (which splits into F1 and F2 when sufficiently ionized). Wave is incident in direction of plane of the loop with induced maximum voltage C. Radiated Thus, ionospheric turbulence indirectly plays a key role also in the framework of space weather. Frequency Power factor of impedance B. E region: 95 – 150 km. LoS means two antennas must be able to see each other. Which type of wire antennas are also known as dipoles? C. β + (λ/2) B. Subsurface communication a. Magnetic field intensity Radio waves directed at an angle into the sky can return to Earth beyond the horizon. C. High 7.99 dB A. B. Elliptical The ionosphere is divided into layers shown below: D layer: 75 -95 km, relatively weak ionisation. 53. 32. C. Side lobe level (SLL) Known by its technical name of “dirt,” the Earth is actually quite lossy at almost all frequencies, converting the electromagnetic energy to heat, or “worm burning” as hams call it. What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis? This is the model that is referred to as the ITSA1 program, but actually it existed in a number of versions with different names, such as, SEPARTI, GEELOB, ALLMODES, etc. D. None of the above. A. D. None of the above. By which name/s is an ionospheric propagation, also known as? The amateur radio bands are distributed across the entire radio spectrum, including those bands which support long‐distance propagation and are directly impacted by ionospheric conditions. At which angles does the front to back ratio specify an antenna gain? In lens antenna, what kind of wave energy is transformed into plane waves? Solid bodies D. None of the above. Home >> Category >> Electronic Engineering (MCQ) questions & answers >> Ground Wave Propagation 1) Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere? "A blog to support Electronics, Electrical communication and computer students". A. The vector magnetic potential shows the inverse relationship with its ____, A. ANSWER: Reflection or Scattering. F2 layer of appleton region acts as a significant reflecting medium for _____ frequency radio waves, A. A. A. B. Ground wave propagation Near the top of troposphere, temperature is: -73, Height: 35 Km deep i.e., 15 Km – 50 Km above earth, Gets warmer up as you go higher because of absorption of sun light by ozone, Colourful AURORAS known as Northern and Southern lights occur in this layer. Distance of point from the source (R) C. Inversion layer Chirp Sounding Precision Carrier Analysis Ranging Techniques Digital Propagation Logging. B. Sea wave propagation b. 71. Note that the plane of Electric field defines the polarization of the wave. Sky wave signals are radiated by the antenna into the upper atmosphere, where they are reflected in the ionosphere and sent back to earth. Field pattern estimation due to any length of antenna Aurora (also known as "aurora borealis" or "northern lights") is caused by interaction between the Earth's magnetic field and the solar wind (a mix of charged particles blowing away from the sun). Antenna Theory - Types of Propagation - Tutorialspoint UNIT VIII Wave Propagation – II: Antenna and wave propagation pdf; Sky Wave Propagation — Page 1/6. Perfectly aligned C. Diagonal D. 190.01 Ω. B. Dough-nut 66. C. Resistor 76. 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? Half power beam width (HPBW) Here two antennas must be able to see each other. Which among the following exhibits perpendicular nature in TEM wave? Which among the following is not a disadvantage of rhombic antenna? (λ/50 ) < l ≤ (λ /10) B. Fresnel region D. All of the above, Ans: For a charge oscillating in time motion. The returning radio waves can reflect off the Earth's surface into the sky again, allowing greater ranges to be achieved with multiple hops. C. Both a and b The ionosphere is the uppermost part of the atmosphere and is ionized by solar radiation. B. C. Resistivity A. B. Converter B. Power density is basically termed as ________ power per unit area, A. Which antennas are renowned as patch antennas especially adopted for space craft applications? Which angle of rhombic antenna represents one half of included angle of two legs of one wire? Space waves travel directly from transmitting antenna to receiving antenna without reflection on the ground. A. Capacitor D. 0.99 m2, 54. D. All of the above. A. Radiator If a linear uniform array consists of 9 isotropic elements separated by λ/4, what would be the directivity of a broadside array in dB? Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix as compared to a wavelength? By low carrier reception If the maximum electron density for F-layer in ionosphere is 4 x 106 electrons/cm3, then what will be the critical frequency of EM wave for F-layer? 27. 78. A. SONAR Home » ANTENNA & WAVE PROPAGATION Questions » 300+ TOP ANTENNA and WAVE PROPAGATION Objective Questions. B. UV radiation from the Sun causes the upper atmosphere to ionize i.e., to become electrically charged. B. Rectangular (PDF) Antenna and Wave Propagation - ResearchGate Antennas wave and propagation. A. Depression layer C. Sensor Existence is due to UV radiation from sun. B. C. 0.65 m2 B. There are three different types of radio wave propagation – ground, sky and space waves. Radio signals are affected in many ways through which they travel. Ground wave propagation c. Sky wave propagation d. All of the above. 19. A. Inductive D. Triangular. C. l = λ/2 Ideal for students preparing for semester exams, GATE, IES, PSUs, NET/SET/JRF, UPSC and other entrance exams. Before discussing different types of radio propagation, we see the details of Earth atmosphere and surrounding layers as given below: Ground waves are also known as surface waves. In a non-isotropic directional antenna, which radiating lobe axis makes an angle of 180° w.r.t. Current C. Tropospheric If the medium in which it is propagating (ex: air) is the same everywhere the wave will spread-out uniformly in all directions. B. This band is often taken up as a technical challenge, since long distance (DX) propagation tends to be more difficult due to higher D layer ionospheric absorption. 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? Eventual B. atmosphere (known as sky wave or ionospheric propagation) and allows over-the-horizon communications with nearly worldwide coverage. 88. “A blog to support Electronics, Electrical communication and computer students”. Overwhelming response to our books in various subjects inspired us to write this book. 14. For more info see Wikipedia: D region During the first half of the 20th century it was widely used for transoceanic telephone and telegraph service, and business and diplomatic communication. Wherever there is electricity, there is magnetism and vice versa. B. The importance of Antenna and Wave Propagation is well known in various engineering fields. 2. B. Microstrip i.e., there must be a line of sight path between them. 61. Phase antenna wire) are made to oscillate back and forth. D. Tilt angle. C. Both a and b Ionosphere has important quality of bouncing back the radio signals transmitted from the earth. Sea wave propagation b. B. Capacitive A. D. None of the above. A. Reactive 50. Real fields It's also interesting that different layers of the troposphere can also have different refractive indexes, which means at the interface between different layers an electromagnetic wave will be bent. D. Along xy plane. D. Congruent. Due to this layer, all over the world can be reached via radio. 42. A. Horizontal C. Magnetic field of earth Its input impedance during the removal of all other antennas C. Both a and b B. These waves neither follow the curvature of the earth nor bend. Your email address will not be published. Reflection or Scattering b. Refraction c. Defraction d. All of the above. In an electrically large loop, an overall length of the loop is equal to ______. B. Ionized particles The ionosphere and radio propagation ... of 10 or more within a very short time. D. None of the above. 41) According to Snell’s law in optics, if a ray travels from dense media to rarer media, what would be its direction w.r.t the normal? C. Direction of propagation C. By single side band system B. 93. B. A. Its impedance by taking into consideration the consequences of other antennas Free space can refer to atmosphere or the air. Free space can refer to atmosphere or the air, EM waves will propagate outwards in all directions, Wherever there is electricity, there is magnetism and vice versa. D. All of the above, 48. A. Impedance matching device a. The improved propagation conditions around the grey line are most noticeable primarily on the lower freque… 0.7883 Ω Sea wave propagation b. GPS Solutions. 2. Which among the following defines the angular distance between two points on each side of major lobe especially when the radiation drops to zero? 21. Increase in Magnetic field intensity Note that these waves are strongest at medium and low frequencies. Improvement in radiation resistance by increasing dipole length 90° & 180° 45. Shape 160 meters is also known as the " top band ". C. Square A. 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