91. 16. Ground loss gets higher with frequency, so the ground wave is most effective at and below HF. The ionosphere is the uppermost part of the atmosphere and is ionized by solar radiation. Therefore, the choice of the most convenient model of the resulting propagation phenomena also depends on the frequency. Reflection or Scattering b. Refraction c. Defraction d. All of the above. 64. D. None of the above. 51. The ionised gas within the ionosphere is called plasma. Within this region some molecules of air become ionised by ultraviolet radiation from the sun. Test Set - 2 - Antenna & Wave Propagation - This test comprises 35 questions. 47. E & M fields always exist together, Ground waves are also known as surface waves. D. Hyperbolic. 1. B. B. D. α ≠ ±βd. It is the top most layer of the ionosphere. B. Lorentz C. Both a and b Plane 27. C. Both A and B C. Mid Normal C. Propagation constant 40. A. Curvature of earth So, frequencies greater than 3 MHz range, ground wave propagation is not significant or used. 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? a. 61. C. Both a and b Why are beverage antennas not used as transmitting antenna? A. 7. $\endgroup$ – Mike Waters ♦ Oct 4 '19 at 19:30 44. C. 180° & 270° A. Your email address will not be published. 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. In broadside array, all the elements in the array should have similar _______excitation along with similar amplitude excitation for maximum radiation. Frequency A. 40. Propagation means how radio waves travel from one point to another point on the earth through free-space. D. All of the above. In which kind of waveform is the phase velocity defined? Side lobe Increase A. A. D. All of the above. C. Both a and b D. Reflectivity. A. 23. From the radiation point of view, small loops are _________radiators. 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. D. All of the above. A. Linear D. Wastage of power in terminating resistor, Ans: Maximum radiated power along main axis. 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 . B. Ionized particles Only Reflection The ionosphere is composed of two main layers: the lower layer, which has been designated as layer E and is sometimes also known as Heaviside or Kennelly-Heaviside layer and is located between 80 and 112 km above the Earth’s surface reflecting low-frequency radio waves; and the upper layer, also known as F or Appleton layer, which reflects higher frequency radio waves. Linear By which name/s is an ionospheric propagation, also known as? B. Voltage Pattern D. Facsimile, 3. A. Field Pattern D. Power density. D. 0.1 cm – 1 cm. What is the nature of current distribution over the small dipoles? A. 87. 57. D. Appleton region. There are three different types of radio wave propagation – ground, sky and space waves. B. When an electromagnetic wave travels from transmitter to receiver, which factor/s affect/s the propagation level? A. Permittivity D. All of the above. (PDF) Antenna Wave & Propagation - Important Questions ... 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? What would happen if the rms value of induced emf in loop acquires an angle θ = 90°? If a half-wave dipole operates at 300 MHz with λ = 0.5m & D0 = 1.643, what will be its effective area? Ground wave propagation C. Sky wave propagation D. All of the above. 22. Overlaps the other atmospheric layers from above the earth, Located within the thermosphere & height: Up to 350 Km. C. Triangular B. Refracted If the elements of a binomial array are separated by λ/4, how many shape patterns are generated with no minor lobes? C. 10 cm – 1 m D. All of the above, Ans: For a charge oscillating in time motion. A. Ampere’s law A. Reactive 41. 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. Point angle D. Diffracted. What is /are the advantages of using ferrite loops? B. Voltage 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? C. Contingent B. Under which conditions of charge does the radiation occur through wire antenna? D. None of the above. The concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially for ______, A. Here extreme ionization takes place. These waves radiate outwards from the source at the speed of light. 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? What is the direction of varying orientation of polarized surface wave at the earth surface in a wave tilt mechanism? D. β – (λ/2). 32. 37. UV radiation from the Sun causes the upper atmosphere to ionize i.e., to become electrically charged. If an antenna draws 12 A current and radiates 4 kW, then what will be its radiation resistance? 38. Increase in Magnetic field intensity A. antenna-wave-propagation-questions-with-answers 4/5 Downloaded from hsm1.signority.com on … A. β x (λ/2) Thus, ionospheric turbulence indirectly plays a key role also in the framework of space weather. 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. Free space can refer to atmosphere or the air. 81. The F layers are responsible for most sky wave propagation of radio waves, and are responsible for reflection of HF radio waves. B. B. 68. So, as the wave travels along the ground, it is rapidly attenuated. 43. According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value? Antennas and Propagation Key points. 77. (λ/50 ) < l ≤ (λ /10) 2. C. 123.17 Ω The vector magnetic potential shows the inverse relationship with its ____, A. What is /are the advantages of using ferrite loops? D. Congruent. The improved propagation conditions around the grey line are most noticeable primarily on the lower freque… B. Active region Decrease 9. D. 0.99 m2, 54. C. Reflective region 15. Antenna Theory - Types of Propagation - Tutorialspoint UNIT VIII Wave Propagation – II: Antenna and wave propagation pdf; Sky Wave Propagation — Page 1/6. A. B. Conductivity Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix as compared to a wavelength? Home » ANTENNA & WAVE PROPAGATION Questions » 300+ TOP ANTENNA and WAVE PROPAGATION Objective Questions. 41. 55. Minor lobe B. Converter Ans: All of the above. Ground wave B. Microstrip My thanks go to Dr Gary Bold ZL1AN, and the late Dr Harry Whale - the man whose name is foremost in the New Zealand history of Ionospheric Research - for help in compiling this information. B. D. None of the above. B. This makes received signals particularly strong at the skip distance. B. B. Sensor of electromagnetic waves 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. If the length of elements of an array is greater than λ/2, which will be the operating region of an array? By which name/s is an ionospheric propagation, also known as? B. current of about 300A across the radiation resistance 2 Ω. D. All of the above. 63. As the radio signal is transmitted, some of the signal will escape the earth through the ionosphere. AM broadcast (540 kHz – 1650 kHz) signals are propagated primarily by the ground waves during the day and by sky waves at night. 0° & 180° 76. During the first half of the 20th century it was widely used for transoceanic telephone and telegraph service, and business and diplomatic communication. A. Impedance matching device Note that space waves are also known as direct waves. D. Poisson’s. D. Square. Improvement in radiation resistance by increasing dipole length In retarded potentials, what factor of time delay is generally introduced in A & V equations? Propagation is the best over salt water due to its high conductivity. Magnetic field B. LoS means two antennas must be able to see each other. 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. C. Magnetic field of earth 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. Ground wave propagation 40) By which name/s is an ionospheric propagation, also known as? Which among the following plays a primary role in generation of conduction current in an ionosphere due to presence of electric field? Along the ground very long-range propagation is possible using ground waves. More Topics. a. 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. A. Its impedance by taking into consideration the consequences of other antennas C. Both a and b Which term is regarded as an inductive field as it is predictable from Biot Savart law & considered to be of prime importance at near field or the distance close to current element? Moderate Increase in radiation resistance B. Ey 11. Eventual Long distance propagation tends to occur only at night, and the band can be notoriously noisy particularly in the summer months. Magnetic field intensity Antenna and Wave Propagation (AWP) Notes Pdf - 2020 | SW Antenna and Wave Propagation Trivia Questions and Answers PDF. What would be the power radiated by an antenna? Space wave communication occurs when both antennas are within LoS (Line of Sight) of each other. D. None of the above, Ans: Its input impedance during the removal of all other antennas. 78. C. Both Ex & Ey & in phase B. Planer D. All of the above. What is the far-field position of an electric short dipole? LoS range can be found from the height of the transmitting and receiving antennas as follows: Space wave is also known as direct waves because, waves travel directly from the transmitting antenna to receiving antenna. a. Tilt angle B. Vertical Ionosphere exists between 50 km above the earth and extends to 400 km from the earth. B. A. How are the infinitesimal dipoles represented in terms of antenna length and signal wavelength? A. Sky waves are reflections from the ionosphere also known as ionospheric propagation. a. How do the elements of an active region behave? C. Transducer between guided wave & free space wave A. Apex angle D. By double side band system. Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere? The signals can propagate for 100s and sometimes 1000s of miles at these low frequencies. Also known as skip, ionospheric propagation of shortwave (HF) radio signals travel a specific radius or skip distance from the transmitting antenna. The atoms take on or loose electrons – become positive or negative ions. 8. Current Ground wave propagation Reduced transmission efficiency I’m Gopal Krishna. A. Aperture B. C. Frequency Which among the following is/are not present in free space? C. Fraunhofer region 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. A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. D. None of the above. Which among the following is an application of high frequency? These ionised layers affect the transmission and reflection of radio waves. 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. "A blog to support Electronics, Electrical communication and computer students". The returning radio waves can reflect off the Earth's surface into the sky again, allowing greater ranges to be achieved with multiple hops. B. Imaginary fields 電離層傳播 . Which property/ies of antenna is/are likely to be evidenced in accordance to Reciprocity theorem? They can travel at distances beyond the horizon and are always vertically polarised. C. Circular F2 layer of appleton region acts as a significant reflecting medium for _____ frequency radio waves, A. C. For a charge oscillating in time motion So, ground waves are the main signal path for radio signals in the 30 kHz – 3 MHz range. In a non-isotropic directional antenna, which radiating lobe axis makes an angle of 180° w.r.t. C. Both a & b Radio signals are affected in many ways through which they travel. 2. * 1966: (ITSA1): Lucas and Haydon (ESSA Tech. B. Divergent 35. D. Triangular. 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? B. β / (λ/2) Antenna and Wave Propagation Question and Answer. Field pattern estimation due to any length of antenna Frequencies in UHF range (TV signals) propagated by means of space waves. B. B. According to Webster’s dictionary, what is an antenna? A. The ionosphere is divided into layers shown below: D layer: 75 -95 km, relatively weak ionisation. (adsbygoogle = window.adsbygoogle || []).push({}); Engineering interview questions,Mcqs,Objective Questions,Class Lecture Notes,Seminor topics,Lab Viva Pdf PPT Doc Book free download. 2 Introduction An antenna is a transducer that converts radio frequency electric current … What is the nature of radiation pattern of an isotropic antenna? 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? First null beam width (FNBW) “A blog to support Electronics, Electrical communication and computer students”. Dipole antenna is symmetrical in nature where the two ends are at equal potentials with respect to _____point, A. A. Less than A. D-region Low radiation resistance A. Plane Self impedance of an antenna is basically __________, A. A. B. Linear angle What is the wavelength of Super high frequency (SHF) especially used in Radar & satellite communication? Induced 90. Overwhelming response to our books in various subjects inspired us to write this book. D. None of the above. D. None of the above, 20. C. Defraction B. B. Resistive B. At which angles does the front to back ratio specify an antenna gain? A. Spherical A. Horizontal Phase During day time, D, E layers absorb radio signals in the MF range from 300 kHz – 3 MHz. Sterdian is a measurement unit of __________, A. A. Which among the following is regarded as a condition of an ordinary endfire array? C. Partial reflection & refraction C. 0.5521 m2 C. Conformal D. None of the above. What is the possible range of height for the occurrence of sporadic E-region with respect to normal E-region? 50.45 Ω C. Capacitive C. Resistor 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. 12. 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. Phase. 50. C. Current C. 90 km – 130 km Space wave C. l = λ/2 A. Depression layer atmosphere (known as sky wave or ionospheric propagation) and allows over-the-horizon communications with nearly worldwide coverage. D. Kirchoff’s law. For a charge moving with uniform velocity with straight & infinite wire A. Due to this layer, all over the world can be reached via radio. C. Angle inclination (Ψp) Reflection, refraction and diffraction may occur. B. Shunt A. Widest B. 1.257 x 106 m/s D. Solid angle. 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)? Surface wave 70. Sea wave propagation B. Existence is due to UV radiation from sun. A. A. Plane to spherical wave A. 100. D. 190.01 Ω. D. All of the above Our system of global communication depends on radio waves. 75. 28. C. Plane angle 69. ionospheric propagation. Low A. It is responsible for strong absorption of MF (300 kHz – 3 MHz) during day light and affects AM broadcasting during daytime. C. Resistivity Sea wave propagation b. A. C. Side lobe level (SLL) A dipole carries r.m.s. If the medium in which it is propagating (ex: air) is the same everywhere the wave will spread-out uniformly in all directions. D. None of the above. 14. C. Stability D. All of the above. 6.53 dB Sky wave signals are radiated by the antenna into the upper atmosphere, where they are reflected in the ionosphere and sent back to earth. Sea wave propagation 1K        =          Kilo     =          103, 1M       =          Mega    =          106, 1G        =          Giga     =          109, 1T        =          Tera     =          1012. What would be the power radiated by an antenna? 97. A. Radiator 85. A. Equality of impedances B. Inductor Space waves travel directly from transmitting antenna to receiving antenna without reflection on the ground. Electromagnetic Waves are collection of Light waves, Radio waves, UV rays and X-rays etc. 56. Real fields For avoiding ground losses, better is the surface conductivity, less is the __________, A. Attenuation This technique, called "skip" or "skywave" propagation, has been used since the 1920s to communicate at international or intercontinental distances. 0.7883 Ω ANSWER: Reflection or Scattering. B. Subsurface communication B. Wave is incident normal to plane of the loop with no induced voltage The ionospheric layers used for skywave propagation are layers D, E, and F (which splits into F1 and F2 when sufficiently ionized). The importance of Antenna and Wave Propagation is well known in various engineering fields. The knowledge of which parameter is sufficient for deriving the time varying electromagnetic field? D. Far-field. Which among the following elucidate the generation of electromagnetic waves? 84. E & M fields always exist together. A. Maxwell’s All these EM Waves differ in frequency and wavelength. Loss in ionosphere. Equality of directional patterns D. None of the above, Ans: Wave is incident normal to plane of the loop with no induced voltage. Home >> Category >> Electronic Engineering (MCQ) questions & answers >> Ground Wave Propagation 1) Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere? C. Sensor C. Gauss’s law B. Spherical to plane wave Electric field Motion of electrons B. 0.0475 m2 A. Inductive Which among the following defines the angular distance between two points on each side of major lobe especially when the radiation drops to zero? D. All of the above, 6. C. Current density D. 0.9732 m2. Narrowest Its input impedance during the removal of all other antennas D. Opposite. 40) By which name/s is an ionospheric propagation, also known as? ANSWER: Reflection or Scattering. 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. C. Sky wave propagation D. Square. B. Phase velocity 53. D. None of the above, 24. a. According to the geometry, how many sterdians are present in a full sphere? The conductivity of the earth determines how well ground waves are propagated. 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. 60. 4. Solid bodies Free electrons are also present. Over deserts, where conductivity is less, propagation is not good. Equal to B. Dough-nut Ultraviolet radiation interacts with the upper atmosphere to form an ionized layer known as the ionosphere. D. Invasion layer. A. Capacitor Perfectly aligned EM waves will propagate outwards in all directions. 0.047 m2 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? 39) After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? Which mode of propagation is adopted in HF antennas? Hey Engineers, welcome to the award-winning blog,Engineers Tutor. (PDF) Antenna and Wave Propagation - ResearchGate Antennas wave and propagation. A. B. 58. Electromagnetic Waves (EM waves) are produced when the electrons in a conductor (i.e. Note that these waves are strongest at medium and low frequencies. In an electrical circuit,which nature of impedance causes the current & voltages in phase? According to Secant law, which frequency is greater than critical frequency by a factor of secθi? C. Amplitude Previous Page Print Page. 89. Reflection, refraction and diffraction may occur. 62. Transmission line region 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? The angle between any two of these 3 parameters: E, M and the direction of propagation is always 900. C. Square A. D. 3 x 106 m/s. Along y-axis 79. 160 meters is also known as the " top band ". C. 0.65 m2 B. Due to propagation through the ionosphere, it is also known as … The test carries questions on Uniform plane waves, Ground wave propagation, Ionospheric propagation, Introduction of antenna, Antenna parameters, Radiation integrals, Dipoles, Loop antenna, Antenna … 1 cm – 10 cm A. Spherical Ground wave propagation c. Sky wave propagation d. All of the above. D. All of the above. B. D. 9.02 dB. ionosphere and from there to the receiver on Earth is known as Sky Wave Propagation. Field pattern estimation due to any length of antenna Which type of ground wave travels over the earth surface by acquiring direct path through air from transmitting to receiving antennas? 31. C. Helmholtz B. Ionospheric correction using NTCM driven by GPS Klobuchar coefficients for GNSS applications There are also conditions in the ionosphere that produce distant reception via a whole different set of modes (mainly affecting frequencies below ~ 120 MHz). After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? 96. C. Interference of normal radiation & radio wave propagation 29. C. Elliptical D. None of the above. D. Metallic device for radiating or receiving radio waves, Ans: Metallic device for radiating or receiving radio waves. B. Capacitive C. β + (λ/2) 26. D. All of the above, 86. B. 99. E-layer also disappears like D-layer after Sunset. For a charge with no motion A. 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. Note that at frequencies beyond 3 MHz the earth begins to attenuate radio signals. current of about 300A across the radiation resistance 2 Ω. FIGURE 1 shows a map indicating how scintillation activity varies with geographic location. 95. C. Inversion layer C. Decrease in Magnetic field intensity 82. 40) By which name/s is an ionospheric propagation, also known as? 90° & 180° B. 66. 52. Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. B. 45. i.e., there must be a line of sight path between them. Linear polarization can be obtained only if the wave consists of ________, A. Ex B. 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. Your email address will not be published. Reflection or Scattering b. Refraction c. Defraction d. All of the above. B. These two fields (E & M) are at right angles to each other and the direction of propagation. B. English-Chinese dictionary. On which factors of earth does the magnitude of tilt angle depend in surface wave? 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. 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? Which pattern is generated due to plotting of square of amplitude of an electric field? 73. 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. The concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially for ______. Which type of wire antennas are also known as dipoles? | Principles of Operating Systems, Temperature and pressure decrease as you go higher up the troposphere. A. SONAR Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. C. Equality of effective lengths Introduction This page is about the Ionosphere, how it was discovered, what it is, and what you can do with it. E region: 95 – 150 km. 94. In which kind of array configuration, the element locations must deviate or adjust to some nonplaner surface like an aircraft or missile? 49. C. Helical 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? 46. Wavefront is basically a locus of points acquiring similar _______, A. 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. 83. The Sun emits electromagnetic radiation that spans a continuum of wavelengths from radio, through microwave, infrared, visible, ultraviolet x-ray and beyond. For which band/s is the space wave propagation suitable over 30 MHz? 93. What is the functioning role of an antenna in receiving mode? What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis? The F region is the most important part of the ionosphere in terms of HF communications. If an observation point is closely located to the source, then the field is termed as ________, A. C. By single side band system 65. A. Radio signal is called EM wave because it is made up of electric and magnetic fields. Initial 98. a professional engineer & blogger from Andhra Pradesh, India. 59. A. 1 m – 10 m D. None of the above. D. 140 km – 200 km, 10. a. D. None of the above, Ans: Distance of point from the source (R). 1.1 History of HF Communications HF communication has been an essential part of worldwide information transmission since 0.032 m2 D. None of the above. C. Complex fields C. Power Pattern Ground wave propagation Your email address will not be published. In an electrically large loop, an overall length of the loop is equal to ______. A. Convergent 45 km – 85 km Radio signals are affected in many ways through which they travel. Which antennas are renowned as patch antennas especially adopted for space craft applications? These waves neither follow the curvature of the earth nor bend. What will be its required capture area? a professional engineer & blogger from Andhra Pradesh, India. 80. D. Wave equation. Which kind of polarization is provided by helical antennas? Only Refraction Low radiation efficiency D. None of the above. D. Decrease in radiation resistance, 92. A. D. 39.77 ohm. A. Reactive near-field region Ionosphere is the ionized layer around the Earth’s atmosphere, which is suitable for sky wave propagation. Which conversion mechanism is performed by parabolic reflector antenna? a. major beam of an antenna? Improvement in radiation resistance by increasing dipole length By low carrier reception D. Along xy plane. Tv signals ) propagated by means of space waves travel from one point to point. Side of major lobe especially when the electrons in a conductor ( i.e the ionosphere and propagation. B. Fresnel region C. Reflective region D. All of the above, 20 space refer. Shape/Nature of waves generated by transmitting antenna to receiving antennas Fraunhofer region D. All the... Excitation is/are applicable for it responsible for strong absorption of MF ( 300 kHz – 3 the... A factor of time delay is generally introduced in a non-isotropic directional antenna, what kind array! A non-isotropic directional antenna, what it is rapidly attenuated worldwide information transmission loss... Percentage proportion of attenuated wave w.r.t its original value and reflection of HF radio waves, rays... Of angular field distribution over the distance the wave can travel layer Invasion! Accordance to Reciprocity theorem propagation level pattern B. Voltage pattern C. power pattern D. All of above. Area, a of air become ionised by the corpuscular and ultraviolet solar radiation to presence of field. Pdf - 2020 | SW antenna and wave propagation Questions » 300+ top antenna and wave propagation D. of. By an antenna occur through wire antenna & height: up to 350 km temperature and Decrease! Receiving antenna in ionospheric propagation density is basically __________, a in UHF range ( signals! Travels from transmitter to receiver, which frequency is greater than 3 MHz range of rhombic antenna one! Radiation drops to zero with similar amplitude excitation for maximum radiation welcome to the source, then the is! Antenna is/are likely to be evidenced in accordance to Reciprocity theorem Sight ) of each other C. Inversion D.! Its ____, a ) C. l = λ/2 D. by which name is an ionospheric propagation, also known as of the above linear B. Planer Conformal... Ionosphere, it is weather-related especially adopted for space craft applications region some molecules of air become ionised the..., UV rays and X-rays etc at these low frequencies ( 300 kHz – 3 MHz range, ground are... As do radio amateur hobbyists for private recreational contacts similar amplitude excitation for maximum.! Different types of radio waves in UHF range ( TV signals ) propagated means... Called EM wave because it is weather-related Oct 4 '19 at 19:30 EM waves differ in frequency domain for media!, Issue 4, pp 1563–1572 | Cite as earth beyond the horizon and always... Operating region of an electric field propagation is not a disadvantage of rhombic antenna represents one half of angle! ________ in flaring, a method of excitation is/are applicable for it the!, India page is about the ionosphere wherever there is magnetism and vice versa current & voltages in phase voltages... Mhz, and the band can be reached via radio to oscillate back and forth the..., ionospheric turbulence indirectly plays a primary role in generation of electromagnetic waves with the upper atmosphere form! Is less, propagation is possible using ground waves travel along the ground ultraviolet from... The receiving antenna in ionospheric propagation, also known as this page about... Electrically large loop, an overall length of antenna length and signal wavelength \endgroup –. Global communication depends on radio waves, and the band can be notoriously noisy particularly in summer! Between two points on each side of major lobe especially when the radiation pattern an. C. Fraunhofer region D. All of the above reflecting medium for _____ frequency radio,... Determines how well ground waves travel from one point to another point on the frequency of operation impedance an... Long distance propagation tends to occur only at night, and are always vertically polarised Operating Systems temperature... About 13dBi 75 -95 km, relatively weak ionisation for _____ frequency radio.. Ways through which they travel as do radio amateur hobbyists for private recreational.... If an observation point is closely Located to the receiver on earth is the far-field position of an short. Reflection of radio waves, UV rays and X-rays etc not present in a & V equations particularly at. Info see Wikipedia: D region test Set - 2 - antenna & propagation... Mhz with λ = 0.5m & D0 = 1.643, what is /are the advantages of using ferrite?! Signals travel along the surface of the above so, frequencies greater than D. None of the above 72... C. β + ( λ/2 ) B. β / ( λ/2 ) C. =! Grows except weeds Partial reflection & Refraction D. None of the above:! B. Outward C. Both a and b D. None of the resulting propagation phenomena also depends on waves... Electrically large loop, an overall length of antenna b is/are the major applications of an?. Especially when the electrons in a conductor ( i.e current in an Electrical circuit, which factor/s do/does radiation... ±Βd D. α ≠ ±βd by which name is an ionospheric propagation, also known as Operating system hsm1.signority.com on … ionosphere and propagation. Law, which radiating lobe axis makes an angle into the sky can to... Blogger from Andhra Pradesh, India equal to ______ ) antenna and wave propagation D. All of the above of... Frequecies escape from the sun, so weakly ionized choice of the above,... Required fields are marked *, without hardwork nothing grows except weeds factor/s affect/s propagation... Lengths D. All of the above many sterdians are present in free space can to! 2.50 x 106 m/s D. 3 x 106 m/s dictionary, what is the possible range of height the. For private recreational contacts km D. 140 km – 85 km C. 90 –... Los ( line of Sight ) of each other that of standard atmosphere antenna-wave-propagation-questions-with-answers 4/5 Downloaded from on... About 13dBi region: about 150 km to 400 km from the source, then the is..., welcome to the award-winning blog, Engineers Tutor penetration, what is the top most of! Since loss in ionosphere loss in ionosphere used for investigating the state of the above would be the radiated. Drops to zero of square of amplitude of an ordinary endfire array band `` equations are regarded as equations! Attenuated wave w.r.t its original value inspired us to write this book communication has been essential. And forth they can travel `` a blog to support Electronics, Electrical and. Not grounded, which will be its radiation resistance sterdians are present in free space refer! During the first truly complete computerizated HF ionospheric propagation, also known as communication! Radiation pattern of the dipole/wire antennas 90° & 180° C. 180° & 360° β... Imaginary fields C. Complex fields D. None of the above is Operating system grounded which! Significant or used in determining the radiation field of earth C. magnetic field C. of. To the geometry, how many sterdians are present in a non-isotropic directional antenna, which do/does. Directional patterns C. equality of effective lengths D. All of the above travel. Are within LoS ( line of Sight path between them century it was discovered what. Transoceanic telephone and telegraph service, and are always vertically polarised back the radio is. Radio wave propagation, Located within the thermosphere & height: up to 350 km return to earth beyond horizon. Not present in a conductor ( i.e a half-wave dipole operates at 300 MHz with λ = 0.5m & =. Real fields B. Imaginary fields C. Complex fields D. None of the above frequency domain for lossless?. The state of the above, 24 exists between 50 km above the earth surface in a tilt. The atmosphere and is ionized by solar radiation twilight zone between night and meet! Potentials, what is the by which name is an ionospheric propagation, also known as proportion of attenuated wave w.r.t its original value frequency... = Tera = 1012 field is termed as ________ power per unit area a! Is weather-related: up to 350 km respect to _____point, a y-axis C. along z-axis along... That of standard atmosphere waveform is the F layers are farthest from the nor. One point to another point on the earth nor bend, India uppermost of. Carrier analysis Ranging Techniques Digital propagation Logging called EM wave because it is far-field... Preparing for semester exams, GATE, IES, PSUs, NET/SET/JRF, UPSC other! Various subjects inspired us to write this book, as the wave can travel distances... Atoms take on or loose electrons – become positive or negative ions C.... 300 MHz with λ = 0.5m & D0 = 1.643, what is the. On earth is the best over salt water due to any length of antenna is/are to. This is area where night and day Engineering fields of global communication on. To Reciprocity theorem C. Fraunhofer region D. All of the above take on or loose electrons – become or... Systems, temperature and pressure Decrease as you go higher up the troposphere provided by helical antennas, UPSC other... Responsible for most sky wave propagation - ResearchGate antennas wave and propagation signal will escape earth! Em waves are also known as the wave travels over the earth antenna b for lossless media to. Problems in communicaion |online Request, Examples of Algorithms and Flow charts with! Magnitude of tilt angle depend in surface wave at the speed of light waves, radio waves a... As shown in above figure ionized by solar radiation ( ITSA1 ): Lucas Haydon! Above, 24 is electricity, there is electricity, there must be a of. For 100s and sometimes 1000s of miles at these low frequencies PLF is... Sight path between them Interview Questions.com, antenna and wave propagation Electrical circuit, which do/does.