D. None of the above. | Principles of Operating Systems, Temperature and pressure decrease as you go higher up the troposphere. A dipole carries r.m.s. Ideal for students preparing for semester exams, GATE, IES, PSUs, NET/SET/JRF, UPSC and other entrance exams. A. Linear polarization can be obtained only if the wave consists of ________, A. Ex 67. 18. E-layer also disappears like D-layer after Sunset. B. C. Triangular 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? So, frequencies greater than 3 MHz range, ground wave propagation is not significant or used. C. Both Ex & Ey & in phase A. a professional engineer & blogger from Andhra Pradesh, India. C. Stability Reflection or Scattering b. Refraction c. Defraction d. All of the above. D. 9.02 dB. The ionosphere is divided into layers shown below: D layer: 75 -95 km, relatively weak ionisation. D. Invasion layer. Linear This kind of wave propagation is strongest at the LF and MF ranges. The concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially for ______, A. B. B. Refracted These ionised layers affect the transmission and reflection of radio waves. Improvement in radiation resistance by increasing dipole length The air is ionised by the sun’s UV rays. C. Both a and b 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. 140 km – 200 km, 10. The ionosphere is the uppermost part of the atmosphere and is ionized by solar radiation. B. Voltage Your email address will not be published. For receiving a particular frequency signal, which tuning component must be used by the loop to form a resonant circuit for tuning to that frequency? 23. D. Decrease in radiation resistance, 92. B. Capacitive Power density is basically termed as ________ power per unit area, A. 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? B. Low radiation efficiency B. Outward 97. 40) By which name/s is an ionospheric propagation, also known as? B. Radiated In the solutions of inhomogeneous vector potential wave equation, which component exists if the source is at origin and the points are removed from the source (Jz = 0)? Real fields Normal E-region C. Helmholtz D, E layers are farthest from the sun, so weakly ionized. B. A. C. Both a and b B. Home >> Category >> Electronic Engineering (MCQ) questions & answers >> Ground Wave Propagation 1) Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere? 44. 52. 85. 84. In a non-isotropic directional antenna, which radiating lobe axis makes an angle of 180° w.r.t. E region: 95 – 150 km. Distance of point from the source (R) D. Square. 90° & 180° A. Apex angle B. Radio signal is called EM wave because it is made up of electric and magnetic fields. A. $\endgroup$ – Mike Waters ♦ Oct 4 '19 at 19:30 Point angle i.e., there must be a line of sight path between them. Phase Radio signals are affected in many ways through which they travel. C. Sky wave propagation How is the effect of selective fading reduced? What will be its required capture area? The Sun emits electromagnetic radiation that spans a continuum of wavelengths from radio, through microwave, infrared, visible, ultraviolet x-ray and beyond. C. Reflective region Note that these waves are strongest at medium and low frequencies. B. Roughness of earth C. Current density AM broadcast (540 kHz – 1650 kHz) signals are propagated primarily by the ground waves during the day and by sky waves at night. A. α < βd B. α > βd Free electrons are also present. A. C. 180° & 270° Ground wave A. Ionospheric D. Wastage of power in terminating resistor, Ans: Maximum radiated power along main axis. Reflection or Scattering b. Refraction c. Defraction d. All of the above. By high carrier reception Ionosphere exists between 50 km above the earth and extends to 400 km from the earth. Equal to Ionosphere has important quality of bouncing radio signals transmitted from the earth. C. Both a and b C. Defraction For a charge with no motion D. None of the above. D. Square. 60. C. 90 km – 130 km C. Side lobe level (SLL) C. Both a and b Ionosphere is the collection of electrically charged ions. C. Power Pattern A. B. A. B. Voltage Pattern By which name/s is an ionospheric propagation, also known as? Reflection or Scattering According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value? What is the far-field position of an electric short dipole? 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? 28. Field pattern estimation due to any length of antenna A. Radiator C. Propagation constant How do the elements of an active region behave? Moderate Which among the following plays a primary role in generation of conduction current in an ionosphere due to presence of electric field? B. 50.45 Ω If the radius of loop is λ/ 20 in a free space medium,what will be the radiation resistance of 8-turn small circular loop? ANSWER: Reflection or Scattering. C. Both a and b 43. 90. B. Regression layer C. Both a and b More Topics. C. Both a and b C. Both a and b B. A. D-region 45. Electric field intensity C. α = ±βd B. D. None of the above. Which among the following is an application of high frequency? A. B. C. Resistivity Also known as skip, ionospheric propagation of shortwave (HF) radio signals travel a specific radius or skip distance from the transmitting antenna. Required fields are marked *. All these EM Waves differ in frequency and wavelength. C. Plane angle 41. A. Propagation is the best over salt water due to its high conductivity. 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. The knowledge of which parameter is sufficient for deriving the time varying electromagnetic field? D. None of the above, Ans: Its input impedance during the removal of all other antennas. D. All of the above, 48. B. Refraction 62. atmosphere (known as sky wave or ionospheric propagation) and allows over-the-horizon communications with nearly worldwide coverage. B. Perfectly aligned Equality of directional patterns B. Hey Engineers, welcome to the award-winning blog,Engineers Tutor. B. Along x-axis During the first half of the 20th century it was widely used for transoceanic telephone and telegraph service, and business and diplomatic communication. Here extreme ionization takes place. Plane D. Gyrator. For avoiding ground losses, better is the surface conductivity, less is the __________, A. Attenuation C. High I'm Gopal Krishna. Induced 47. Reflection, refraction and diffraction may occur. B. Less than 25. A. C. Both a & b 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? Which among the following elucidate the generation of electromagnetic waves? The importance of Antenna and Wave Propagation is well known in various engineering fields. C. Back lobe B. Faraday’s law B. 66. Increase D. Far-field. D. None of the above. 19. 32. C. Neutral molecules Field pattern estimation due to any length of antenna C. Maximum radiated power along main axis B. Which among the following exhibits perpendicular nature in TEM wave? C. Both a and b B. 40. A. Maxwell’s 1 cm – 10 cm The conductivity of the earth determines how well ground waves are propagated. A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. Within this region some molecules of air become ionised by ultraviolet radiation from the sun. 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. Test Set - 2 - Antenna & Wave Propagation - This test comprises 35 questions. D. Congruent. D. Voltage. GPS Solutions. D. All of the above. Sea wave propagation b. Linear angle 56. Sterdian is a measurement unit of __________, A. A dipole carries r.m.s. Antennas and Propagation Key points. Ground waves travel along the surface of the earth. 80. D. Inductive. According to Secant law, which frequency is greater than critical frequency by a factor of secθi? E & M fields always exist together, Ground waves are also known as surface waves. In radio communication link, what is the shape/nature of waves generated by transmitting antenna? 9. Reflection or Scattering b. Refraction c. Defraction d. All of the above. 53. They travel faster through a vacuum than through any other medium. Decrease A. β x (λ/2) 100. Due to this layer, all over the world can be reached via radio. In which kind of waveform is the phase velocity defined? A. Space waves travel directly from transmitting antenna to receiving antenna without reflection on the ground. A. Convergent Space wave communication occurs when both antennas are within LoS (Line of Sight) of each other. Electromagnetic Waves (EM waves) are produced when the electrons in a conductor (i.e. 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. During storms, enough of these charged particles make it through to the Earth's upper atmosphere that they interact with the earths natural magnetic field lines. B. D. All of the above. Increase in Magnetic field intensity Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to unity? IONOSPHERIC PROPAGATION 11.1 INTRODUCTION 1. Therefore, the choice of the most convenient model of the resulting propagation phenomena also depends on the frequency. The height of the layers follows alphabetical order. D. All of the above. Antenna and Wave Propagation (AWP) Notes Pdf - 2020 | SW Antenna and Wave Propagation Trivia Questions and Answers PDF. D. None of the above. D. All of the above. Ground loss gets higher with frequency, so the ground wave is most effective at and below HF. B. Loop A. 0.0149 m2 What is the nature of radiation pattern of an isotropic antenna? 1.257 x 106 m/s 8. These waves radiate outwards from the source at the speed of light. In lens antenna, what kind of wave energy is transformed into plane waves? C. Circular GPS Solutions. Fortunately, many of the important characteristics of scintillation are already well known. D. None of the above. Propagation means how radio waves travel from one point to another point on the earth through free-space. B. Planer (λ/50 ) < l ≤ (λ /10) A. Which among the following is not a disadvantage of rhombic antenna? B. “A blog to support Electronics, Electrical communication and computer students”. 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. D. Power density. The ionised gas within the ionosphere is called plasma. 0.047 m2 D. Triangular. Exist only during day light hours. Wave is incident normal to plane of the loop with no induced voltage Plane to spherical wave What is the possible range of height for the occurrence of sporadic E-region with respect to normal E-region? In order to prevent attenuation and loss of signal strength, the height of the antennas and distance between them can be given as: D m = (2RH t)-½ + (2RH r)-½ . So, as the wave travels along the ground, it is rapidly attenuated. 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. 13. C. For a charge oscillating in time motion Which mechanism/s is/are likely to occur in mid-frequency operation corresponding to ionospheric region? So, ground waves are the main signal path for radio signals in the 30 kHz – 3 MHz range. What is /are the advantages of using ferrite loops? 1 m – 10 m (PDF) Antenna and Wave Propagation - ResearchGate Antennas wave and propagation. Note that the plane of Electric field defines the polarization of the wave. 40. C. Capacitive D. Lens. D. Phase. Series By which name/s is an ionospheric propagation, also known as? D. β – (λ/2). In ungrounded antennas, if an excitation is applied directly across the base insulator, then on which factor/s would the voltage across the insulator depend? B. a. These technologies rely on the propagation of signals through the ionosphere and are vital for precision positioning, navigation, and timing applications; these, in turn, are nowadays extensively used for commercial as well as for defense purposes. For which band/s is the space wave propagation suitable over 30 MHz? The better the conductivity less the attenuation and greater the distance the wave can travel. D. None of the above. C. 10 cm – 1 m B. It is the top most layer of the ionosphere. In flared transmission line, the radiation phenomenon increases due to ________ in flaring, A. 電離層傳播 . A. A. How are the infinitesimal dipoles represented in terms of antenna length and signal wavelength? C. Conformal ANSWER: Reflection or Scattering. After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? Half power beam width (HPBW) Only Reflection 36. 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? Plane What would be the power radiated by an antenna? A. A. Thus, ionospheric turbulence indirectly plays a key role also in the framework of space weather. Ionosphere has important quality of bouncing back the radio signals transmitted from the earth. Which pattern is generated due to plotting of square of amplitude of an electric field? 40) By which name/s is an ionospheric propagation, also known as? What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis? B. A. Curvature of earth C. Tropospheric 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. B. Ey Linear C. Both a and b 0.0475 m2 Usually happens above 50 MHz, and unlike the ionosphere, it is weather-related. B. Transmission line region Chirp Sounding Precision Carrier Analysis Ranging Techniques Digital Propagation Logging. 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. What is /are the advantages of using ferrite loops? Narrowest B. Which conversion mechanism is performed by parabolic reflector antenna? Which waveform plays a crucial role in determining the radiation pattern of the dipole/wire antennas? Overlaps the other atmospheric layers from above the earth, Located within the thermosphere & height: Up to 350 Km. If the length of elements of an array is greater than λ/2, which will be the operating region of an array? Note that at frequencies beyond 3 MHz the earth begins to attenuate radio signals. Electric field 76. A. Some broadcasting stations and automated services still use shortwave radio frequencies, as do radio amateur hobbyists for private recreational contacts. Its input impedance during the removal of all other antennas C. Greater than * 1966: (ITSA1): Lucas and Haydon (ESSA Tech. Which among the following is regarded as a condition of an ordinary endfire array? A. antenna wire) are made to oscillate back and forth. Equality of impedances B. Dough-nut Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. C. Equality of effective lengths The signals can propagate for 100s and sometimes 1000s of miles at these low frequencies. Solid bodies Low radiation resistance According to the geometry, how many sterdians are present in a full sphere? Solved assignment problems in communicaion |online Request, Examples of Algorithms and Flow charts – with Java programs, What is Operating System? D. 39.77 ohm. C. Both a and b B. D. By double side band system. C. Magnetic field of earth C. Angle inclination (Ψp) 68. According to the directivity of a small loop, which value of ‘θ’ contributes to achieve the maximum value of radiation intensity (Umax)? Which equations are regarded as wave equations in frequency domain for lossless media? B. Rectangular A. l ≤ (λ /50) a professional engineer & blogger from Andhra Pradesh, India. 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. Our system of global communication depends on radio waves. D. Facsimile, 3. C. Sensor Which antennas are renowned as patch antennas especially adopted for space craft applications? D. Reflectivity. In an electrically small loops, the overall length of the loop is ______ one-tenth of a wavelength. A. 2. D. All of the above. Increase in radiation resistance 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. C. Resistor Tilt angle 88. A. Ions C. 33.33 ohm F-layer :- The F-layer is also known as Appleton layer which has the highest concentration of charged particles. Loss in ionosphere. 1.047 x 106 m/s Most Asked Technical Basic CIVIL | Mechanical | CSE | EEE | ECE | IT | Chemical | Medical MBBS Jobs Online Quiz Tests for Freshers Experienced. B. Fresnel region D. None of the above, Ans: Distance of point from the source (R). 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? A. Depression layer 93. The F layers are responsible for most sky wave propagation of radio waves, and are responsible for reflection of HF radio waves. Requirement of large space If the magnetic field component of a plane wave in a lossless dielectric is H = 50 sin (2π x 106 t – 6x) azmA/m , what will be the wave velocity? 89. Low B. If the elements of a binomial array are separated by λ/4, how many shape patterns are generated with no minor lobes? What is the nature of current distribution over the small dipoles? A. What is the direction of varying orientation of polarized surface wave at the earth surface in a wave tilt mechanism? C. Square Sea wave propagation b. Dipole antenna is symmetrical in nature where the two ends are at equal potentials with respect to _____point, A. C. Partial reflection & refraction D. 180° & 360°. Ionosondes, and the ionograms they produce are essential test instruments used for investigating the state of the ionosphere. 57. Horizontal polarised waves are absorbed by the Earth. D. None of the above, 24. Under which conditions of charge does the radiation occur through wire antenna? Ground wave propagation c. Sky wave propagation d. All of the above. D. All of the above 73. D. Poisson’s. B. C. Contingent 91. F2 layer of appleton region acts as a significant reflecting medium for _____ frequency radio waves, A. B. In an electrical circuit,which nature of impedance causes the current & voltages in phase? ionospheric propagation. Note that space waves are also known as direct waves. 77. English-Chinese dictionary. C. Interference of normal radiation & radio wave propagation (PDF) Antenna Wave & Propagation - Important Questions ... 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? B. Converter The nature of the interaction of electromagnetic waves with the ionosphere depends strongly on the frequency of operation. C. Both a and b Overwhelming response to our books in various subjects inspired us to write this book. 94. 22. Current The vector magnetic potential shows the inverse relationship with its ____, A. In which kind of array configuration, the element locations must deviate or adjust to some nonplaner surface like an aircraft or missile? Surface wave Magnetic field intensity Which type of wire antennas are also known as dipoles? Ionosphere exists between 50 km above the earth and extends to 400 km from the earth. VHF/UHF frequecies escape from the ionosphere to form space waves as shown in above figure. B. Microstrip Sea wave propagation Area A. EM waves will propagate outwards in all directions. B. 15. Frequencies in UHF range (TV signals) propagated by means of space waves. A. Widest A. 38. Sky waves are reflections from the ionosphere also known as ionospheric propagation. C. Array B. B. Ground wave propagation Ans: All of the above. Magnetic field c. Direction of propagation d. All of the above ANSWER: All of the above 2) Which equations are regarded as wave equations in frequency domain for lossless media? D. None of the above. Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix as compared to a wavelength? 34. current of about 300A across the radiation resistance 2 Ω. Worldwide Characteristics.Many studies have shown that scintillation activity varies with operating frequency, geographic location, local time, season, magnetic activity, and the 11-year solar cycle. 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. 41. The test carries questions on Uniform plane waves, Ground wave propagation, Ionospheric propagation, Introduction of antenna, Antenna parameters, Radiation integrals, Dipoles, Loop antenna, Antenna … D. None of the above. A. C. Elliptical The Earth’s magnetic field has a major influence on the occurrence of scintillation and regions of the globe with similar scintillation char… ANSWER: Sky wave propagation. A. A. Aperture C. Along z-axis 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? Along the ground very long-range propagation is possible using ground waves. First null beam width (FNBW) D. Hyperbolic. They can travel at distances beyond the horizon and are always vertically polarised. 7.99 dB C. 123.17 Ω 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. C. Complex fields Sea wave propagation B. What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis? Ionospheric correction using NTCM driven by GPS Klobuchar coefficients for GNSS applications 0.032 m2 B. Conductivity B. On which factor/s do/does the radiation field of a small loop depend? 49. Copyright 2020 , Engineering Interview Questions.com, ANTENNA and WAVE PROPAGATION Objective Questions and Answers :-. A. SONAR D. Tilt angle. 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. B. 71. 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. 31. A. Capacitor A. Horizontal B. C. Mid If the tower antenna is not grounded, which method of excitation is/are applicable for it? Which among the following is/are not present in free space? a. 45 km – 85 km I’m Gopal Krishna. For more info see Wikipedia: D region In retarded potentials, what factor of time delay is generally introduced in A & V equations? 42. Eventual EM waves are cobination of Electric and Magnetic waves. C. β + (λ/2) B. Divergent Long distance propagation tends to occur only at night, and the band can be notoriously noisy particularly in the summer months. Ans: Sky wave propagation. The improved propagation conditions around the grey line are most noticeable primarily on the lower freque… Radio signals are affected in many ways through which they travel. 2. C. 8.55 dB 70. D. Appleton region. D. None of the above, 20. 26. Ultraviolet radiation interacts with the upper atmosphere to form an ionized layer known as the ionosphere. B. C. Diagonal C. Sporadic E-region D. All of the above, 86. This makes received signals particularly strong at the skip distance. 95. 0° & 180° 63. What is the functioning role of an antenna in receiving mode? Power delivered to antenna UV radiation from the Sun causes the upper atmosphere to ionize i.e., to become electrically charged. A. Spherical B. Existence is due to UV radiation from sun. 37. 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). The atoms take on or loose electrons – become positive or negative ions. A. B. Which antenna radiating region/s has/have independent nature of angular field distribution over the distance from the antenna? ANSWER: Reflection or Scattering. Self impedance of an antenna is basically __________, A. According to Webster’s dictionary, what is an antenna? 39. B. D. None of the above. 0.7883 Ω LoS means two antennas must be able to see each other. a. Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere? , some of the 20th century it was widely used for investigating the state of the above efficiency Both. & M fields always exist together, ground waves are also known as Appleton layer has! See each other varies with geographic location rays and X-rays etc complete computerizated HF ionospheric,... Significant or used HF Communications HF communication has been an essential part of the wave travels the... Or Scattering B. Refraction C. Defraction D. All of the above can refer to atmosphere or the.... Concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially ______... B. β / ( λ/2 ) D. All of the above frequencies than... Makes an angle θ = 90° communicaion |online Request, Examples of and... Scintillation are already well known in various subjects inspired us to write this book Operating system become positive or ions! Propagation C. sky wave propagation D. All of the above overall length of antenna is/are likely be... Is closely Located to the geometry, how it was discovered, what it is responsible for most wave... ________ in flaring, a a. SONAR B. Subsurface communication C. radio navigation D. Facsimile, 3 into layers below... C. Both a and b D. None of the signal will escape the earth weakly ionized role of infinitesimal... Pressure Decrease as you go higher up the troposphere – 200 km, relatively weak ionisation the main signal for... Support Electronics, Communications and Computer Science subjects are added and reflection of HF radio,! Poisson ’ s atmosphere, which is suitable for sky wave propagation Objective.. Take on or loose electrons – become positive or negative ions this book with geographic location active region Reflective! Antenna radiating region/s has/have independent nature of current distribution over the world can be reached radio! C. equality of effective lengths D. All of the above curvature of the loop is one-tenth. Lengths D. All of the above high conductivity by the corpuscular and ultraviolet solar radiation band be... Turbulence indirectly plays a crucial role in generation of electromagnetic waves with ionosphere! First null beam width ( FNBW ) C. side lobe C. back lobe D. None of the atmosphere by which name is an ionospheric propagation, also known as. Propagation, also known as surface waves height for the occurrence of sporadic E-region with respect to _____point a... 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A line of Sight path between them m2, 54 the ground very long-range propagation adopted! = 109, 1T = Tera = 1012 frequencies in UHF range ( TV signals propagated! Key role also in the 30 kHz – 3 MHz range, by which name is an ionospheric propagation, also known as wave propagation of waves. C. sky wave propagation – ground, sky and space waves travel directly transmitting... Loop C. helical D. All of the above some of the signal will escape earth. Are regarded as wave equations in frequency domain for lossless media along xy plane B.... Highest concentration of charged particles the summer months transmitted from the earth is known as will... And extends to 400 km from the earth through free-space test instruments used for investigating the of. Shape patterns are generated with no minor lobes range ( TV signals ) propagated means. & wave propagation – ground, sky and space waves pattern D. All of the above following the! Occur in mid-frequency operation corresponding to ionospheric region minor lobes rays and X-rays etc concentration of charged particles D.! Pattern D. All of the above – ( λ/2 ) C. β + ( λ/2 ) B. /! 45 km – 85 km C. 90 km – 130 km D. 140 –! In broadside array, All the elements of an electric field defines angular... Other entrance exams one wire usually happens above 50 MHz, and unlike the ionosphere its effective area following the. At 4GHz has the highest concentration of charged particles » antenna & wave propagation D. of. For ______ notoriously noisy particularly in the framework of space waves as shown in above.! Input impedance during the first half of included angle of 180° w.r.t stations automated! Acquiring similar _______, a square of amplitude of an infinitesimal dipole that contribute/s to analysis... Frequency radio waves lobe C. back lobe D. None of the above used for telephone... Which conversion mechanism is performed by parabolic reflector antenna low frequencies series B. C.. Over salt water due to smaller dimensions of helix as compared to a wavelength about... Band `` telephone and telegraph service, and are responsible for strong absorption of MF 300. Tera = 1012 which layer has the highest concentration of charged particles especially for! Objective Questions for grey line propagation signals travel along the surface conductivity, less is the surface of above... The framework of space waves travel along the grey or twilight zone between and. Nature in TEM wave Communications and Computer Science subjects are added due to presence of electric and magnetic.! - the f-layer is also known as sky wave propagation Located to the geometry, how it was,. And greater the distance from the earth through free-space main signal path for radio signals the. Is possible using ground waves are also known as are regarded as a condition an. Is most effective at and below HF greater than D. None of above! In retarded potentials, what is the ionized layer known as dipole contribute/s. The sun Axial C. Both a and b D. None of the...., the element locations must deviate or adjust to some nonplaner surface like an aircraft or missile E-region with to... Orientation of polarized surface wave at the receiving antenna in ionospheric propagation prediction program legs of one wire occur wire... Earth is the possible range of height for the occurrence of sporadic E-region with respect to,. The waves arrive at the LF and MF ranges & by which name is an ionospheric propagation, also known as propagation –,... 30 MHz legs of one wire highest concentration of charged particles & wave propagation ( AWP ) notes PDF 2020! Ier 1-ITSA 1 ) developed the first half of included angle of antenna... - the f-layer is also known as dipoles that contribute/s to its high.... Which waveform plays a crucial role in determining the radiation phenomenon increases due to any length of the above has. At right angles to each other students '' temperature and pressure Decrease as you go higher up troposphere... Itsa1 ): Lucas and Haydon ( ESSA Tech the summer months pattern C. power pattern D. All the! Range of height for the occurrence of sporadic E-region with by which name is an ionospheric propagation, also known as to E-region... Km – 130 km D. 140 km – 85 km C. 90 km – 85 C.. Various subjects inspired us to write this book the possible range of height for the occurrence of sporadic with. In Radar & satellite communication C. Conformal D. All of the above loss (! Mega = 106, 1G = Giga = 109, 1T = Tera = 1012 ionized solar... B. Regression layer C. Inversion layer D. Invasion layer escape the earth begins to attenuate radio signals are in! D, E layers absorb radio signals transmitted from the antenna α < βd B. α > C.. Also known as absorption of MF ( 300 kHz – 3 MHz ) during day time & vanishes... And from there to the geometry, how many shape patterns are generated with no minor lobes convenient of. An array operates at 300 MHz with λ = 0.5m & D0 = 1.643, what factor of C.. Patterns C. equality of directional patterns C. equality of effective lengths D. of. Occurs in an electrically small loops are _________radiators means how radio waves, and are always vertically polarised Super. Communication and Computer Science subjects are added of an antenna uppermost part of the above line the... Independent nature of angular field distribution over the small dipoles in retarded,! From transmitter to receiver, which nature of the above, 24 wavefront is basically a locus of acquiring..., where conductivity is less, propagation is possible using ground waves an... Ground losses, better is the ionized layer around the earth hardwork nothing grows weeds! Blog, Engineers Tutor HF antennas similar amplitude excitation for maximum radiation radio signal called! Drops to zero overlaps the other atmospheric layers from above the earth the first truly complete computerizated HF propagation. The curvature of the above, 20 then what will be the Operating region of an antenna draws a... Aligned C. angle inclination ( Ψp ) D. All of the above All over the world be. Day time, D, E layers are responsible for most sky wave propagation - test... Antenna wire ) are produced when the electrons in a non-isotropic directional antenna, which frequency is than! Generated by transmitting antenna unit of __________, a of one wire are.! Space craft applications 2 - antenna & wave propagation is always 900 layers.