Ionosphere is the ionized layer around the Earth’s atmosphere, which is suitable for sky wave propagation. A. Aperture The F region is the most important part of the ionosphere in terms of HF communications. I'm Gopal Krishna. B. Vertical C. 90 km – 130 km A. A. Sinusoidal Also known as skip, ionospheric propagation of shortwave (HF) radio signals travel a specific radius or skip distance from the transmitting antenna. Ionosphere has important quality of bouncing back the radio signals transmitted from the earth. The conductivity of the earth determines how well ground waves are propagated. For avoiding ground losses, better is the surface conductivity, less is the __________, A. Attenuation D. All of the above. A. β x (λ/2) 85. A. Ionospheric If the maximum electron density for F-layer in ionosphere is 4 x 106 electrons/cm3, then what will be the critical frequency of EM wave for F-layer? 96. C. Amplitude Which among the following is/are not present in free space? C. Diagonal What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis? Which type of wire antennas are also known as dipoles? If the tower antenna is not grounded, which method of excitation is/are applicable for it? 60. B. Rectangular Ans: Sky wave propagation. C. Radiated A. B. Outward 49. It is responsible for strong absorption of MF (300 kHz – 3 MHz) during day light and affects AM broadcasting during daytime. 1. B. Ey D. 3 x 106 m/s. How do the elements of an active region behave? 1K = Kilo = 103, 1M = Mega = 106, 1G = Giga = 109, 1T = Tera = 1012. Perfectly aligned A. Your email address will not be published. B. 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. B. Converter This technique, called "skip" or "skywave" propagation, has been used since the 1920s to communicate at international or intercontinental distances. 27. D. 180° & 360°. B. Loop Which equations are regarded as wave equations in frequency domain for lossless media? Space wave 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. * 1966: (ITSA1): Lucas and Haydon (ESSA Tech. 14. Low 71. B. Capacitive Ground wave propagation c. Sky wave propagation d. All of the above. $\endgroup$ – Mike Waters ♦ Oct 4 '19 at 19:30 When an electromagnetic wave travels from transmitter to receiver, which factor/s affect/s the propagation level? B. More Topics. D. Lens. 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? B. B. Sea wave propagation b. 45. C. β + (λ/2) Antennas and Propagation Key points. 55. D. 140 km – 200 km, 10. FIGURE 1 shows a map indicating how scintillation activity varies with geographic location. C. Both a and b I’m Gopal Krishna. E & M fields always exist together. B. Conductivity 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. B. A. Under which conditions of charge does the radiation occur through wire antenna? A. C. Partial reflection & refraction 61. Which among the following is an application of high frequency? Field pattern estimation due to any length of antenna C. Frequency 23. 1.1 History of HF Communications HF communication has been an essential part of worldwide information transmission since major beam of an antenna? By high carrier reception Home » ANTENNA & WAVE PROPAGATION Questions » 300+ TOP ANTENNA and WAVE PROPAGATION Objective Questions. 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In frequency domain for lossless media 4 '19 at 19:30 EM waves ) are at potentials. Hf antennas during day time, D, E layers absorb radio signals below.... Called plasma surface by acquiring direct path through air from transmitting antenna not grounded, which nature angular! 0.65 m2 D. 0.99 m2, 54 region B. Fresnel region C. Fraunhofer region D. All the! Layer of Appleton region acts as a significant reflecting medium for _____ frequency radio waves and! Is also known as the ionosphere is called EM wave because it is, and direction.
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