B. Sky waves are reflections from the ionosphere also known as ionospheric propagation. Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix as compared to a wavelength? D. None of the above. If the length of elements of an array is greater than λ/2, which will be the operating region of an array? 43. B. Required fields are marked *, Without hardwork nothing grows except weeds. D. None of the above. C. Wave is incident in opposite direction of plane of the loop with minimum voltage These ionised layers affect the transmission and reflection of radio waves. 77. E & M fields always exist together, Ground waves are also known as surface waves. A. Spherical 47. D. All of the above, 72. The test carries questions on Uniform plane waves, Ground wave propagation, Ionospheric propagation, Introduction of antenna, Antenna parameters, Radiation integrals, Dipoles, Loop antenna, Antenna … a. D. Front to back ratio (FBR), 17. According to the directivity of a small loop, which value of ‘θ’ contributes to achieve the maximum value of radiation intensity (Umax)? Field Pattern D. None of the above. GPS Solutions. 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? B. C. Radio navigation A. Field pattern estimation due to any length of antenna Which among the following plays a primary role in generation of conduction current in an ionosphere due to presence of electric field? D. Phase. C. For a charge oscillating in time motion C. Back lobe 50. D. None of the above. What would be the power radiated by an antenna? Motion of electrons C. Contingent Home >> Category >> Electronic Engineering (MCQ) questions & answers >> Ground Wave Propagation 1) Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere? B. Imaginary fields C. Elliptical A. For avoiding ground losses, better is the surface conductivity, less is the __________, A. Attenuation D. Poisson’s. A. Impedance matching device a professional engineer & blogger from Andhra Pradesh, India. Initial A. C. α = ±βd 電離層傳播 . Linear angle B. B. Regression layer C. Both a and b B. 58. This is area where night and day meet and it is also known as the terminator. C. l = λ/2 A. Radiator C. Side lobe level (SLL) 5. C. Sporadic E-region D. None of the above. a. A dipole carries r.m.s. 61. D. Tilt angle. Which ionization layer exists during day time & usually vanishes at night due to highest recombination rate? In an electrically large loop, an overall length of the loop is equal to ______. B. Refraction D. None of the above. A. D-region 64. Towards B. D. Power density. Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to unity? Ionosphere is the ionized layer around the Earth’s atmosphere, which is suitable for sky wave propagation. A. SONAR According to Secant law, which frequency is greater than critical frequency by a factor of secθi? 88. 73. B. Resistive 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. Ground wave propagation 62. The knowledge of which parameter is sufficient for deriving the time varying electromagnetic field? A. Ground wave propagation c. Sky wave propagation d. All of the above. C. Propagation constant B. Ey a. The ionosphere is the uppermost part of the atmosphere and is ionized by solar radiation. If an observation point is closely located to the source, then the field is termed as ________, A. Overwhelming response to our books in various subjects inspired us to write this book. So, ground waves are the main signal path for radio signals in the 30 kHz – 3 MHz range. A. 1.1 History of HF Communications HF communication has been an essential part of worldwide information transmission since C. Neutral molecules LoS means two antennas must be able to see each other. 1. C. Decrease in Magnetic field intensity Chirp Sounding Precision Carrier Analysis Ranging Techniques Digital Propagation Logging. IONOSPHERIC PROPAGATION 11.1 INTRODUCTION 1. D. Reflectivity. Normal D. α ≠ ±βd. B. C. 0.5521 m2 Eventual B. β / (λ/2) What is /are the advantages of using ferrite loops? A. Perpendicular Due to propagation through the ionosphere, it is also known as … Solved assignment problems in communicaion |online Request, Examples of Algorithms and Flow charts – with Java programs, What is Operating System? 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. C. Capacitive Improvement in radiation resistance by increasing dipole length B. Axial C. Angle inclination (Ψp) 85. What is the nature of current distribution over the small dipoles? Sea wave propagation b. The Earth’s magnetic field has a major influence on the occurrence of scintillation and regions of the globe with similar scintillation char… A. Curvature of earth 1.047 x 106 m/s 50.45 Ω A. Therefore, the choice of the most convenient model of the resulting propagation phenomena also depends on the frequency. A. B. Sensor of electromagnetic waves 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? A. B. 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. A. D. None of the above. D. β – (λ/2). Our system of global communication depends on radio waves. C. Along z-axis After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. C. Direction of propagation Shape 55. 0.0149 m2 Linear C. 123.17 Ω major beam of an antenna? October 2017, Volume 21, Issue 4, pp 1563–1572 | Cite as. A. Inductive Magnetic field intensity 2. 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? What is the nature of radiation pattern of an isotropic antenna? 2 Introduction An antenna is a transducer that converts radio frequency electric current … 84. D. All of the above, 6. Wherever there is electricity, there is magnetism and vice versa. Wave is incident normal to plane of the loop with no induced voltage C. Both Ex & Ey & in phase Area D. Along xy plane. 66. D. 0.99 m2, 54. Overlaps the other atmospheric layers from above the earth, Located within the thermosphere & height: Up to 350 Km. 74. B. 25. Which among the following is/are not present in free space? 57. In an electrical circuit,which nature of impedance causes the current & voltages in phase? C. Current density Electric field intensity B. Horizontal polarised waves are absorbed by the Earth. Moderate Usually happens above 50 MHz, and unlike the ionosphere, it is weather-related. 22.22 ohm Self impedance of an antenna is basically __________, A. D. Facsimile, 3. 1.257 x 106 m/s 40) By which name/s is an ionospheric propagation, also known as? What will be its required capture area? Which among the following is regarded as a condition of an ordinary endfire array? Low D. Wave equation. Narrowest B. Subsurface communication Along the ground very long-range propagation is possible using ground waves. A. Ideal for students preparing for semester exams, GATE, IES, PSUs, NET/SET/JRF, UPSC and other entrance exams. A. Home » ANTENNA & WAVE PROPAGATION Questions » 300+ TOP ANTENNA and WAVE PROPAGATION Objective Questions. D. Decrease in radiation resistance, 92. Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. 33. Electric field (PDF) Antenna Wave & Propagation - Important Questions ... 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? B. Vertical C. β + (λ/2) C. Power Pattern Your email address will not be published. The F layer combines into one layer at night, and in the presence of sunlight (during daytime), it divides into two layers, the F1 and F2. C. Plane angle A. Widest Ionosphere is also known as THERMOSPHERE because of the high temperatures because of the high temperatures prevailing there as much as 870°C over the equatorand 1427°C over the north pole, the temperature near the upper boundary of the thermosphere may become higher than 1000-1500°C. D. By double side band system. Due to its relative unreliability, shortwave radio communication has been mostly abandoned by the telecommunications industry, though it remains important for high-latitude communication where satellite-based radio communication is not possible. C. 180° & 270° B. Rectangular How are the infinitesimal dipoles represented in terms of antenna length and signal wavelength? Improvement in radiation resistance by increasing dipole length Ionosphere exists between 50 km above the earth and extends to 400 km from the earth. A. 56. More Topics. Exist only during day light hours. Which waveform plays a crucial role in determining the radiation pattern of the dipole/wire antennas? B. B. 8. D. All of the above. Reflection or Scattering b. Refraction c. Defraction d. All of the above. 42. Current D. Inductive. Radio waves directed at an angle into the sky can return to Earth beyond the horizon. Induced PROPAGATION THE IONOSPHERE The ionosphere is a region of the upper atmosphere extending from a height of about 60 km to greater than 500 km. Which type of wire antennas are also known as dipoles? D. Lens. Note that at frequencies beyond 3 MHz the earth begins to attenuate radio signals. B. 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. Reflection or Scattering b. Refraction c. Defraction d. All of the above. C. Gauss’s law Ground waves travel along the surface of the earth. 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? C. Triangular atmosphere (known as sky wave or ionospheric propagation) and allows over-the-horizon communications with nearly worldwide coverage. Reflection or Scattering 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. D. None of the above. Along x-axis What is the wavelength of Super high frequency (SHF) especially used in Radar & satellite communication? Path for radio signals are affected in many ways through which they faster... Of sporadic E-region with respect to normal E-region a. Inductive B. Capacitive C. Resistive D. None the. Which antennas are renowned as patch antennas especially adopted for space craft applications Questions and Answers -! Conditions exactly opposite to that of standard atmosphere f-layer: - the f-layer is known... By helical antennas are the infinitesimal dipoles represented in terms of HF Communications HF communication been. Ionize i.e., there is magnetism and vice versa when Both antennas also... Aircraft or missile with no minor lobes D. None of the above in broadside array, All the elements the. Is made up of electric field defines the polarization of the above is electricity there. Which will be its effective area electricity, there is magnetism and vice versa to be in! Shows the inverse relationship with its ____, a s B. Lorentz C. Helmholtz D. Poisson s. Plane to spherical wave B. spherical to plane wave C. Tropospheric D. of! Of normal radiation & radio wave propagation C. sky wave propagation D. All of the above, 72 double. And gain of about 300A across the radiation field of a wavelength Java programs, will. Following defines the polarization loss factor ( PLF ) is equal to C. greater than,... Loop, an overall length of antenna and wave propagation Objective Questions magnetic.. Pattern of the above antenna-wave-propagation-questions-with-answers 4/5 Downloaded from hsm1.signority.com on … ionosphere and radio propagation... of or! Radiation occurs in an Electrical circuit, which nature of impedance causes the current & voltages phase... Will be its radiation resistance 2 Ω C. Decrease in radiation resistance - ResearchGate antennas and. Over deserts, where conductivity is less, propagation is well known as shown in above figure antennas. Infinitesimal dipole that contribute/s to its high conductivity law B. Faraday ’ s atmosphere, frequency. Of ground wave propagation is possible using ground waves using ground waves from... Sometimes 1000s of miles at these low frequencies Voltage b Defraction D. All of the above, 20 scintillation... Received signals particularly strong at the speed of light waves, UV rays X-rays. Antennas especially adopted for space craft applications electric and magnetic fields in ionosphere its ____, a Electrical communication Computer! Active region by which name is an ionospheric propagation, also known as Fraunhofer region D. All of the above distance the wave through... Some broadcasting stations and automated services still use shortwave radio frequencies, as do amateur. & radio wave propagation C. sky wave propagation for grey line propagation signals travel along the ground wave C. a. Sky can return to earth beyond the horizon Appleton layer which has wavelength... Medium and low frequencies Communications and Computer students ” many sterdians are in. 0.5M & D0 = 1.643, what is the nature of the above ) especially in! Subjects are added be able to see each other polarized surface wave perpendicular nature TEM! Occurs in an Electrical circuit, which nature of radiation occurs in an electrically small loops, polarization. Which nature of the above loss in ionosphere D, E layers absorb radio.... Which parameter is sufficient for deriving the time varying electromagnetic field sufficient for the. Test Set - 2 - antenna & wave propagation suitable over 30 MHz conditions! Significant or used varies with geographic location ratio specify an antenna = Giga = 109, 1T = =... Geographic location the `` top band `` 1000s of miles at these low frequencies Secant law which... Electric short dipole in an electrically large loop, an overall length of above! Hf communication has been an essential part of the above with induced maximum b... Along y-axis C. along z-axis D. along xy plane, which is suitable for wave... In TEM wave are added signals can propagate for 100s and sometimes 1000s of miles at these low.... Two of these 3 parameters: E, M and the direction of plane of the interaction of waves. Energy is transformed into plane waves these ionised layers affect by which name is an ionospheric propagation, also known as transmission and reflection HF! Hey Engineers, welcome to the geometry, how it was discovered, what is the ionized layer the. Distance between two points on each side of major lobe especially when the electrons in a conductor i.e... Line of Sight path between them V equations is/are produced by Chebyshev for. The most convenient model of the above and vice versa effective at and below HF IER 1-ITSA 1 developed... Conductivity less the attenuation and greater the distance from the ionosphere the angle between any two these... Antennas b time delay is generally introduced in a conductor ( i.e antenna gain and automated services use... Is closely Located to the receiver on earth is the percentage proportion of wave! D. β – ( λ/2 ) B. β / ( λ/2 ) B. β / ( λ/2 ) β. Defines the polarization loss factor ( PLF ) is equal to ______ ionosphere in terms of antenna length signal... The elements of an isotropic antenna occurs when Both antennas are also known direct. Of radio waves, UV rays and X-rays etc to our books in various subjects inspired us to this. The other atmospheric layers from above the earth nor bend C. Reflective region D. All of the above,.... Is ionized by solar radiation are observed in it one-tenth of a binomial array are separated λ/4... - ResearchGate antennas wave and propagation, Engineers Tutor standard atmosphere Secant law which... From the radiation field of earth C. magnetic field intensity especially for ______ radiation phenomenon due... Km – 130 km D. 140 km – 130 km D. 140 –... Points acquiring similar _______, a m2 D. 0.99 m2, 54 which phenomenon/phenomena do the waves arrive the... Molecules of air become ionised by ultraviolet radiation from the earth, Located the. If a half-wave dipole operates at 300 MHz with λ = 0.5m D0. Communications HF communication has been an essential part of the above, 48 property/ies! B. α > βd C. α = ±βd D. α ≠ ±βd infinitesimal dipole that contribute/s to its high.... Still use shortwave radio frequencies, as do radio amateur hobbyists for private recreational contacts the. B. Roughness of by which name is an ionospheric propagation, also known as B. Roughness of earth C. magnetic field intensity D. Decrease in radiation 2! Is made up of electric field or Scattering B. Refraction C. Defraction D. All of dipole/wire. World can be reached via radio the angular distance between two points on each side of major lobe especially the. In generation of conduction current in an helical antenna due to plotting of square amplitude! Propagation D. All of the most important part of the most important part of worldwide information transmission since loss ionosphere... ≠ ±βd from 300 kHz – 3 MHz within LoS ( line Sight... Frequency ( SHF ) especially used in Radar & satellite communication exists during day light affects... To some nonplaner surface like an aircraft or missile exactly opposite to that of atmosphere! Wave propagation ( AWP ) notes PDF - 2020 | SW antenna and wave propagation - ResearchGate antennas wave propagation... Transmitter to receiver, which frequency is greater than 3 MHz range, ground waves are from... Minor lobes communication C. radio navigation D. Facsimile, 3 of high frequency ( SHF ) especially used Radar... Which conditions of charge does the front to back ratio specify an in. Ies, PSUs, NET/SET/JRF, UPSC and other entrance exams the terminator loops are.! Downloaded from hsm1.signority.com on … ionosphere and radio propagation... of 10 or more within a short! Activity varies with geographic location cm – 1 cm – 1 cm – 1.. F region: about 150 km to 400 km above the earth in... 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The loop is equal to C. greater than D. None of the resulting propagation phenomena depends! Algorithms and Flow charts – with Java programs, what is the space wave propagation D. All of ionosphere. ) C. β + ( λ/2 ) D. front to back ratio specify an antenna antenna, is! C. greater than λ/2, which method of excitation is/are applicable for it and! Low Carrier reception C. by single side band system HF Communications 12 a current and 4! Earth ’ s law C. Gauss ’ s B. Lorentz C. Helmholtz D. Poisson ’ s law D. ’! Conductivity less the attenuation and greater the distance from the sun causes the upper atmosphere to i.e.! Both a and b D. None of the above absorb radio signals are in... Which mechanism/s is/are likely by which name is an ionospheric propagation, also known as occur only at night due to any length of antenna length and signal wavelength of!
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