Description : A means of beyond the line-of-sight propagation of microwave signal. A. Space wave B. Microwave link C. Troposcatter D. Point-to-point
Last Answer : C. Troposcatter
Description : ECE Board Exam March 1996 When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ________ wave. A. space or direct B. ground C. surface D. sky
Last Answer : A. space or direct
Description : The decimetric wave is using what method of propagation? A. Ground wave B. Space wave C. Sky wave D. Tropospheric wave
Last Answer : B. Space wave
Description : The rhombic antenna is primarily used for A. ground wave propagation B. space wave propagation C. ionosphere scatter propagation D. sky wave propagation
Last Answer : D. sky wave propagation
Description : What is the resultant field strength at the receiving antenna in space wave propagation under case 2? A. 0 B. ξd C. 2ξd D. 3ξd
Last Answer : C. 2ξd
Description : Highest frequency that can be used for skywave HF communications between two given points on earth. A. Gyro frequency B. Maximum usable frequency C. Critical frequency D. Virtual frequency
Last Answer : B. Maximum usable frequency
Description : Which of the following frequency bands is best suited for ground wave propagation? A. 30 to 300 kHz B. 300 kHz to 3 MHz C. 3 MHz to 30 MHz D. 30 MHz to 300 MHz
Last Answer : A. 30 to 300 kHz
Description : Compare ground wave and space wave propagation on the basis of: (i) Frequency range (ii) Method of propagation.
Last Answer : Compare ground wave and space wave propagation on the basis of: (i) Frequency range (ii) Method of propagation.
Description : This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km. A. Troposcatter B. Ionospheric scatter C. Ducting D. Microwave
Last Answer : B. Ionospheric scatter
Description : Type of transmission path that permits communication in the frequency range from 30 to 60 MHz and over distances form about 1000 to 2000 km. A. Ducting B. Ionospheric scatter C. Microwave D. Troposcatter
Description : Tropospheric scatter is a method of sky wave propagation for which of the following frequency bands? A. 300 kHz to 3 MHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 300 MHz to 3 GHz
Last Answer : D. 300 MHz to 3 GHz
Description : Compare ground wave propagation. Sky wave propagation and space wave propagation.
Last Answer : Sr. N o Parameter Ground Wave Propagation Sky Wave Propagation Space wave Propagation 1 Frequency Range 30 kHz to 3 MHz 3 MHz to 30 MHz frequencies above 30 MHz 2 ... These waves have line of sight propagation, ... 6 Fading Problem less Severe Less
Description : Man-made noise is usually from _______. A. transmission over power lines and by ground wave B. sky-wave C. space-wave D. troposphere
Last Answer : A. transmission over power lines and by ground wave
Description : Which of the following is not one of the natural ways a radio wave may travel from transmitter to receiver? A. Ground wave B. Micro wave C. Sky wave D. Space wave
Last Answer : B. Micro wave
Description : Which of the following layers of the ionosphere has no effect on sky wave propagation during daytime? A. D B. E C. F1 D. F2
Last Answer : A. D
Description : What device measures the angle between two radio frequencies and also the direction of propagation of a wave? A. Densimeter B. Absorption wavemeter C. Goniometer D. Ergometer
Last Answer : C. Goniometer
Description : To obtain the most reliable sky wave propagation the ____ should be used. A. Lowest useable frequency (LUF). B. Maximum useable frequency (MUF). C. Optimum useable frequency (OUF). D. Critical frequency
Last Answer : C. Optimum useable frequency (OUF).
Description : Which if the following layers of the ionosphere has no effect on sky wave propagation during the hours of darkness? A. D B. E C. F1 D. F2
Description : Which of the following frequency bands is best suited for sky wave propagation? A. 30 to 300 kHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 3 GHz to 30 GHz
Last Answer : B. 3 MHz to 30 MHz
Description : An electromagnetic wave is ________ polarized when the electric field lies wholly in one plane containing the direction of propagation. A. Horizontally B. Linearly C. Circularly D. Vertically
Last Answer : B. Linearly
Description : The total propagation delay time from transmission to reception of signals from a ground transmitter to ground receiver with angle of elevation at 10 degrees respectively is A. 273 ms B. 239 ms C. 275 ms D. 260 ms
Last Answer : A. 273 ms
Description : Propagation mode of microwave in a waveguide is known as _______. A. TM B. TE C. SW D. TEM
Last Answer : B. TE
Last Answer : The polarization required in ground wave propagation is vertical (linear).
Description : The antenna efficiency of an HF grounded vertical antenna can be made comparable to that of a half-wave antenna A. By installing a good ground radial system B. By isolating the coax shield from ground C. By shortening the vertical D. By lengthening the vertical
Last Answer : A. By installing a good ground radial system
Description : Which of the following terrain types permits a ground wave to travel the farthest? A. Salt water B. Fresh water C. Sandy D. Rocky
Last Answer : A. Salt water
Description : How can the antenna efficiency of an HF grounded vertical antenna be made comparable to that of a half-wave antenna? A. By lengthening the vertical B. By installing a good ground radial system C. By shortening the vertical D. By isolating the coax shield from ground
Last Answer : B. By installing a good ground radial system
Description : Ratio of the velocity of propagation of a light ray in free space to the velocity of propagation of a light ray in free space in a given material. ∙ A. refractive index ∙ B. standing wave ratio ∙ C. velocity factor ∙ D. propagation velocity
Last Answer : ∙ A. refractive index
Description : Compare sky wave and space wave propagation w.r.t. following points. (i) Frequency range (ii) Effect of fading (iii)Polarization (iv)Application
Last Answer : Sr. No Parameters Sky Wave Propagation Space Wave Propagation 1 Frequency range 3 MHz to 30 MHz Above 30 MHz 2 Effect of fading Problem of fading is ... horizontally Polarized 4 Application RadioBroadcasting (SW Range) Used for TV and FM broadcasting
Description : For a space wave transmission, the radio horizon distance of a receiving antenna with a height of 64 meters is approximately A. 8 km B. 32 km C. 64 km D. 256 km
Last Answer : B. 32 km
Description : Which of the following phenomena is possible is free space medium? A. Reflection of radio wave B. Diffraction of radio wave C. Refraction of radio wave D. Attenuation of radio wave
Last Answer : D. Attenuation of radio wave
Description : A receiver is located 64 km from a space wave transmitting antenna that is 100 meters high. Find the required height of the receiving antenna. A. 36 meters high B. 64 meters high C. 100 meters high D. 182.25 meters high
Last Answer : A. 36 meters high
Description : If a transmitting antenna is 100 meters high and a separate receiving antenna is 64 meters high, what is the maximum space wave communication distance possible between them? A. 18 km B. 72 km C. 164 km D. 656 km
Last Answer : B. 72 km
Description : For a space wave transmission, the radio horizon distance of a transmitting antenna with a height of 100 meters is approximately: A. 10 km B. 40 km C. 100 km D. 400 km
Last Answer : B. 40 km
Description : Any small element of space in the path of a wave may be considered as a source of secondary wavelet. A. De Morgan’s Principle B. Faraday’s Law C. Huygen’s Principle D. Fresnel’s Law of optics
Last Answer : C. Huygen’s Principle
Description : Electromagnetic wave travel at __________ in free space. A. 300,000 km/sec B. 100,000 km/ sec C. 400,000 km/sec D. 200km/sec
Last Answer : A. 300,000 km/sec
Description : The VLF and LF bauds use .............. propagation for communication. (A) Ground (B) Sky (C) Line of sight (D) Space
Last Answer : Answer: A Explanation: VLF (Very Low Frequency) LF (Low Frequency) In general there are three type of propagation.1.Ground Propagation 2.Sky propagation 3.Line-of-sight propagation ... portion of the atmosphere. These low-frequency signals travel in all directions from the transmitting antenna.
Description : Helical antennas are oftenused forsatellite trackingatVHFbecauseof a. troposcatter b. superrefraction c. ionospheric refraction d.theFaradayeffect
Last Answer : d.theFaradayeffect
Description : The total space loss of transmission and reception for two ground stations with uplink frequency 8GHz and a downlink of 6 GHz with angle of elevations of 3˚ and 7˚ A respectively is A. 403 dB B. 100 dB C. 20 dB D. 215 dB
Last Answer : A. 403 dB
Description : ECE Board Exam March 1996 The method of generating FM used by broadcasting station is A. direct B. all of these C. indirect D. insertion
Last Answer : C. indirect
Description : A dielectric waveguide for the propagation of electromagnetic energy at light frequencies a. Stripline b. Microstrip c. Laser beam d. Fiber optics
Last Answer : d. Fiber optics
Description : ________ dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber. a. Material dispersion b. Wavelength dispersion c. Modal dispersion d. Delay dispersion
Last Answer : c. Modal dispersion
Description : Dispersion is used to describe the a. Splitting of white light into its component colors b. Propagation of light in straight lines c. Bending of a beam of light when it goes from one medium to another d. Bending of a beam light when it strikes a mirror
Last Answer : a. Splitting of white light into its component colors
Description : What is the propagation delay when a signal is transmitter by an earth station to a geosynchronous satellite about 38,500 km above earth’s equator and then received by the same earth station? A. 256 msec B. 128 msec C. 300 msec D. 400 msec
Last Answer : A. 256 msec
Description : The round-trip propagation delay between two earth stations through a geosynchronous satellite is A. 500 to 600 ms B. 300 to 400 ms C. 600 to 700 ms D. 400 to 500 ms
Last Answer : A. 500 to 600 ms
Description : The maximum propagation delay of a geostationary satellite is A. 278 ms B. 239 ms C. 300 ms D. 250 ms
Last Answer : A. 278 ms
Description : What is the minimum propagation delay of a geostationary satellite? A. 278 ms B. 239 ms C. 300 ms D. 600 ms
Last Answer : B. 239 ms
Description : What is the phase coefficient in radians per unit length of a transmission line at the frequency of 10 MHz if the velocity of propagation is 2.5x108 m/s? A. 0.25 B. 2.5 C. 0.35 D. 3.5
Last Answer : A. 0.25
Description : What is the propagation velocity of a signal in a transmission line whose inductance and capacitance are 5μH/m and 20μF/m respectively? A. 100x103 m/s B. 100 m/s C. 10x103 m/s D. 100x106 m/s
Last Answer : A. 100x103 m/s
Description : If the velocity of propagation in a certain medium is 200x106 m/s, what is its refractive index? A. 1.3 B. 1.5 C. 1.27 D. 0.67
Last Answer : B. 1.5
Description : What propagation condition is usually indicated when a VHF signal is received from a station over 500 miles away? A. D-layer absorption B. Faraday rotation C. Tropospheric ducting D. Moonbounce
Last Answer : C. Tropospheric ducting