ESAT RHM 2 PART 1

1. It is the process by which the waves travel through a medium.

2. It is the term for broadcasting using electromagnetic waves with intention.

3. It is the orientation of the electric field vector in respect to the surface of the Earth.

4. What type of propagation usually occurs from one hand- held VHF transceiver to another nearby?

5. When a signal is returned to earth by the ionosphere, what is this called?

6. At HF frequencies, line-of-sight transmission between two stations uses mainly the:

7. It is classified according to the bend radius of curvature.

8. Bends having a large radius of curvature relative to the fiber diameter.

9. The science of sound.

10. The angle between the normal and the path of a wave through the second medium.

11. The complementary colors of light are:

12. It is also known as line-of-sight communications, direct wave communications and space wave communications, which uses microwave frequencies to transmit information.

13. It is a hollow metal tube designed to carry microwave energy from one place to another, and it is usually made from copper, aluminum or brass extruded to long rectangular or circular pipes.

14. It is when the electrical energy propagates in different modes.

15. It is a system of communications employing an apparatus that transforms a sound wave into an electrical wave, transmits the electrical wave over a suitable medium, then transforms the electrical wave back into a sound wave at the receiver.

16. A point-to-point radio link is to be established between Zamboang del Norte and Zamboanga del Sur, with a distance of 48 km. NTC allowed the use of 6.5 GHz for the link. Initial survey showed that the line of sight is obstructed be a 30 m-building, 15 km away from one of the locations. What will be the minimum height of the antennas, in m to clear from the obstruction?

17. A simple STDP switch placed across the tip and ring, and is mechanically connected to the telephone handset so that when the telephone is idle, the switch is open; when the telephone is in use, the switch is closed.

18. It is the receiver for the telephone which converts electrical signals received from the local loop to acoustical signals that can be heard and understood by a human being.

19. It is the science, study, or technology dealing with light transmission.

20. It is the internal material of the fiber, specifically the central part of the fiber where the light propagates.

21. It is a special lacquer, silicone or acrylate coating that is generally applied to the outside of the cladding.

22. It is the branch of optical technology concerned with transmission of radiant power (light energy) through fibers.

23. Which of the following is/are the basic function of fiber optic data link?

24. The optical source launches the optical signal into the fiber. The optical signal will become progressively weakened and distorted because of ___________.

25. The electric field is parallel to the surface of the Earth, while the magnetic field is perpendicular to the surface of the Earth.

26. A polarization where the magnitude of the electric and magnetic field are not equal.

27. Causes the polarization of radio waves to rotate as it passes through the ionosphere and is a complex process involving the presence of ionized particles and the Earth's magnetic field.

28. The radio wave which follows a path from the transmitter to the ionosphere and back to earth is known correctly as the:

29. What causes the ionosphere to form?

30. Which ionospheric region is closest to the earth?

31. The following can cause microbending loss:

32. Same as intermodal dispersion:

33. When different colors of light travel through different materials and different waveguide structures at different speeds,______ will happen.

34. The compactness of a substance or mass per unit volume

35. The refraction of light waves that causes the different frequencies to bend at slightly different angles.

36. The reflection of the original sound wave as it bounces off a distant surface.

37. It is when the H field is perpendicular to the direction of propagation.

38. It is the ideal mode, specifically a single mode of propagation that is achieved by using only the mode with the lowest cut-off frequency.

39. The effective isotropic radiated power measured at the focal point of a 24 dBi gain antenna is 64 watts, what is the power in dBm produced by the transmitter if it is connected to a gain antenna via a lossless transmission line?

40. It is the apparent velocity at which the wave appears to move along the wall of the guide based on the way the phase angle varies along the walls, and it is always greater than the speed of light in vacuum.

41. It is basically a microwave communications employing a spacecraft placed in orbit around the Earth, relaying signals from point-to-point.

42. Is a satellite radio repeater located inside the satellite.

43. Is a type of satellite that simply reflects a signal back to the Earth.

44. A special balanced transformer used to convert a two-wire circuit (local loop) into a four-wire circuit (telephone set) and vice versa, thus enabling full duplex operation over a two-wire circuit.

45. Is a simple two-of-eight encoding scheme where each digit is represented by the linear addition of two frequencies.

46. It is normally as 20 Hz, 90 Vrms signal. Its purpose is to ring the bell in the telephone set to alert the subscriber that there is an incoming call.

47. Encapsulates the buffer jacket which increases the tensile strength of the overall cable assembly.

48. It is made up of a plastic core and a plastic cladding.

49. It is made up of a glass core and glass cladding.

50. Passive components used to make fiber connections affect the performance of the data link. These components can also prevent the link from operating. Fiber optic components used to make the optical connections includes _________.

51. Fiber performance depends on the amount of loss and signal distortion introduced by the fiber when it is operating at a specific wavelength. Long-haul systems requires ________?

52. Fiber optic systems have many attractive features that are superior to electrical systems. Which of the following is/are the advantages of a Fiber optic systems?

53. It is a surface of constant phase of the wave that is formed when two points of equal phase on rays propagated from the same source are joined together.

54. It is the ability of an insulator to concentrate electric flux, and it determines the capacity of a medium to store electrostatic energy.

55. It is the rate at which energy flows through a unit area of surface in space, and it is inversely proportional to the square of the distance from the source.

56. What two sub-regions of ionosphere exist only in the daytime?

57. When is the ionosphere least ionized?

58. What is the main reason the 160, 80 and 40 metre amateur bands tend to be useful only for short-distance communications during daylight hours?

59. A digital radio system, using 2.5 GHz is to be established between point Toledo City to Asturias, Cebu at 50km distance. You want to know if the link is feasible using the available data below by determining the signal level at each stage of the link. Assuming no obstruction along the path, what is the RSL of the link in dBm? Transmit power = 30 dBm Receiver sensitivity = 117 dB Cables: 2(0.2 x 3 dB) = 1.2 dB Connectors 2 x 0.5 dB = 1 dB Antenna Tx & Rx Gain = 20 dB each Miscellaneous losses = 10 dB

60. The radiation of radio waves into space.

61. The loss of rf energy each time a radio wave is reflected from the Earth's surface

62. A frequency that is a whole number multiple of a smaller base frequency.

63. The center wire of a coaxial cable can be extended into the waveguide to form a______.

64. It is made from the side of the waveguide. A circular hole is used in directional couplers in the walls between the main and auxiliary arms of the waveguide.

65. Is a type of waveguide which consists of sections capable of movements.

66. It was the first active Earth satellite by Russia which is capable of amplifying, reshaping, regenerating, and retransmitting information.

67. It was a telecommunication satellite for Mabuhay Philippines Corporation.

68. The first nanosatellite of the Philippines which was launched to space on June 29, 2018.

69. It is a two-tone signal comprised of 480 Hz and 620 Hz. It is sent from the switching machine back to the calling station when the called telephone number is off hook.

70. The simplest and most straightforward form of telephone service.

71. Is the most common telephone jack in use today and can have up to six conductors.

72. It is a cable configuration wherein the fiber is surrounded by a primary and secondary buffer comprised of Kevlar yarn.

73. It is the band of high frequencies that is too low to be seen by the human eyes with wavelengths ranging between 770 nm and 10^6 nm.

74. It is the band of frequencies that are too high to be seen by the human eye with wavelengths ranging between 10 nm and 390 nm.

75. Which of the following is/are the advantages of a Fiber optic systems?

76. Which of the following is/are the advantages of a Fiber optic systems?

77. It was developed in 1971. This light source was suitable for low-loss coupling to optical fibers.

78. It is directly proportional to the square root of power density and inversely proportional to the distance from the source.

79. It occurs when some of the energy from the electromagnetic waves is transferred to the atoms and molecules of the atmosphere causing some radio waves to be absorbed.

80. In HF radio communications, typically what percentage of the maximum usable frequency (MUF) is the best frequency to use for optimum transmission (FOT)?

81. It explains on how an electromagnetic wave reacts when it meets the interface of two mediums that have different indices of refraction.

82. The position of the E layer in the ionosphere is:

83. What is the maximum distance along the earth's surface that is normally covered in one hop using the F2 region?

84. Skip zone is:

85. It is the angle at which total internal reflection occurs.

86. Bound rays propagate through an optical fiber core by ______.

87. An engineer wants to establish a radio link between point "A" and "B", approximately 80 miles apart. The path is unobstructed and the height of the antenna for Point "A" is more or less fix at 800 above sea level, how high should his antenna be at Point "B" to establish a good radio communication link?

88. Waves that are radiated with their E field component parallel to the Earth's surface.

89. The point where two lines drawn on a graph cross each other.

90. The process of upsetting electrical neutrality.

91. It is a junction consisting of two waveguides coupled together in such a manner that a traveling wave in either guide will induced a traveling wave in the same direction in the other guide.

92. It is a multiport microwave coupling device having a number of terminals so arranged that energy entering one terminal is transmitted to the next adjacent terminal in a particular direction.

93. These are used when it is required to separate or combine two or more signals or for simpler interconnections.

94. It states that for equal intervals of time a satellite will sweep out equal areas in the orbital plane, focused at the barycenter (Earth).

95. It is the trajectory followed by the satellite in equilibrium between two opposing forces (gravitational and centrifugal force).

96. It is the general term to the point farthest to the primary body.

97. It is that portion of the local loop that is strung between poles.

98. It is simply a passive conductor wrapped around a core and placed in series with a cable creating a small electromagnet.

99. It is the optimum level of a test tone on a channel at some point in a communications system, however, its numerical value does not describe the total signal power present at that point rather it merely defines what the ideal level should be.

100. It states that when visible light or high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted (Photoelectric effect).