Chapter 6 Quiz

Chapter 6: Propagation

1. What causes the ionosphere to form? A. Lightning ionizing the outer atmosphere. B. Solar radiation ionizing the outer atmosphere. C. Release of fluorocarbons into the atmosphere. D. Temperature changes ionizing the outer atmosphere. 2. What type of solar radiation is most responsible for ionization of the outer atmosphere? A. Microwave. B. Ionized particles. C. Ultraviolet. D. Thermal. 3. Which ionospheric layer is closest to the earth? A. The E region. B. The D region. C. The F region. D. The A region. 4. Which region of the ionosphere is least useful for long distance communications? A. The F2 region. B. The F1 region. C. The D region. D. The E region. 5. What two sub-regions of the ionosphere exist only in the daytime? A. Troposphere and the stratosphere. B. Electrostatic and electromagnetic. C. D and E. D. F1 and F2. 6. When is the ionosphere most ionized? A. Dawn. B. Midnight. C. Midday. D. Dusk. 7. When is the ionosphere the least ionized? A. Shortly before dawn. B. Just after noon.

C. Just after dusk. D. Shortly before midnight. 8. Why is the F2 region mainly responsible the longest distance radio-wave propagation? A. Because it exists only at night. B. Because it is the lowest ionospheric region. C. Because it does not absorb radio waves as much as other ionospheric regions. D. Because it is the highest ionospheric region. 9. What is the main reason the 160, 80 and 40 meter amateur bands tend to be useful only for short-distance communications during daylight hours? A. Because of auroral propagation. B. Because of D-region absorption. C. Because of magnetic flux. D. Because of lack of activity. 10. During the day, one of the ionospheric layers split into two parts called the: A. D1 & D2. B. E1 & E2. C. A & B. D. F1 & F2. 11. The position of the E layer in the ionosphere is: A. below the D layer. B. below the F layer. C. sporadic. D. above the F layer. 12. What effect does the D layer of the ionosphere have on lower frequency HF signals in the daytime? A. It absorbs the signals. B. It bends the radio waves out into space. C. It refracts the radio waves back to earth. D. It has little or no effect on 80 meter radio waves. 13. What causes the ionosphere to absorb radio waves? A. The presence of ionized clouds in the E region. B. The ionization of the D region. C. The splitting of the F region. D. The weather below the ionosphere. 14. How do sunspots change the ionization of the atmosphere? A. The more sunspots there are, the greater the ionization. B. The more sunspots there are, the less the ionization. C. Unless there are sunspots, the ionization is zero. D. They have no effect.

15. How long is the average sunspot cycle? A. 17 years. B. 5 years. C. 11 years. D. 7 years. 16. What is solar flux? A. A measure of the tilt of the earths ionosphere on the side toward the sun B. The number of sunspots on the side of the sun facing the earth. C. The radio energy emitted by the sun. D. The density of the sun’s magnetic field 17. What is the solar flux index? A. Another name for the American sunspot number. B. A measure of the solar activity that compares daily readings with results of the last six months. C. A measure of solar activity that is taken at a specific frequency. D. A measure of the solar activity that is taken annually. 18. What influences all radiocommunications beyond ground-wave or line-of-sight ranges? A. The F2 region of the ionosphere. B. The F1 region of the ionosphere. C. Solar activity. D. Lunar tidal effects. 19. Which two types of radiation from the sun influence propagation? A. Subaudible and audio-frequency emissions. B. Polar region and equatorial emissions. C. Infra-red and gamma-ray emissions. D. Electromagnetic and particle emissions. 20. When sunspot numbers are high, how is the ionosphere affected? A. Frequencies up to 40 MHz or higher are normally useable for long- distance communications. B. High frequency radio signals are absorbed. C. Frequencies up to 100 MHz or higher are normally useable for long- distance communications. D. High frequency radio signals become weak and distorted. 21. All communication frequencies throughout the spectrum are affected in varying degrees by the: A. ionosphere. B. aurora borealis. C. atmospheric conditions. D. sun.

22. Average duration of the solar cycle is: A. 11 years. B. 3 years. C. 6 years. D. 1 year. 23. The ability of the ionosphere to reflect high frequency radio signals depends on: A. the amount of solar radiation. B. the power of the transmitted signal. C. the receiver sensitivity. D. upper atmosphere weather conditions. 24. Propagation cycles have a period of approximately 11: A. years. B. months. C. days. D. centuries. 25. At what point in the solar cycle does the 20-meter band usually support worldwide propagation during daylight hours? A. Only at the minimum point of the solar cycle. B. Only at the maximum point of the solar cycle. C. At any point in the solar cycle. D. At the summer solstice. 26. Communication on the 80 meter band is generally most difficult during: A. daytime in summer. B. evening in winter. C. evening in summer. D. daytime in winter. 27. During summer daytime, which bands are the most difficult for communications beyond the ground wave? A. 160 and 80 meters B. 40 meters. C. 30 meters. D. 20 meters. 28. The radio wave which follows a path from the transmitter to the ionosphere and back to earth is known correctly as: A. F layer. B. surface wave. C. ionospheric wave. D. skip wave. 29. Reception of high frequency (HF) radio waves beyond 4000 km is generally possible by: A. ground wave.

B. ionospheric wave. C. skip wave. D. surface wave. 30. When a signal is returned to earth by the ionosphere, what is this called? A. Tropospheric propagation. B. Ground-wave propagation. C. Sky-wave propagation. D. Earth-moon-earth propagation. 31. Skywave is another name for: A. ionospheric wave. B. tropospheric wave. C. ground wave. D. inverted wave. 32. That portion of the radiation which is directly affected by the surface of the earth is called: A. tropospheric wave. B. ionospheric wave. C. inverted wave. D. ground wave. 33. A line-of-sight transmission between two stations uses mainly the: A. troposphere. B. Skip wave. C. Ionosphere. D. Ground wave. 34. The distance traveled by ground waves: A. depends on the maximum usable frequency. B. is more on higher frequencies. C. is less at higher frequencies. D. is the same for all frequencies. 35. What is skip zone? A. An area that is too far away for ground wave or sky-propagation. B. An area covered by sky-wave propagation. C. An area that is too far away for ground-wave propagation, but too close for sky-wave propagation. D. An area covered by ground-wave propagation. 36. What is the maximum distance along the earth’s surface that is normally covered in one hop using the F2 region? A. 2160 km (1200 miles). B. None; the F2 region does not support radio-wave propagation.

C. 4500 km (2500 miles). D. 325 km (180 miles). 37. Which ionospheric region most affects sky-wave propagation on the 6 meter band? A. The F2 region. B. The F1 region. C. The E region. D. The D region. 38. What is the maximum distance along the earth’s surface that is normally covered in one hop using the E region? A. 2160 km (1200 miles). B. 325 km (180 miles). C. 4500 km (2500 miles). D. None; the E region does not support radio-wave propagation. 39. Skip zone is: A. a zone of silence caused by lost sky waves. B. A zone between two refracted waves. C. A zone between the end of the ground wave and the point where the first refracted wave returns to earth. D. A zone between the antenna and the return of the first refracted wave. 40. What type of propagation would best be used by two stations within each other’s skip zone on a certain frequency? A. Scatter mode. B. Sky-wave. C. Ducting. D. Ground-wave. 41. How does the range of sky-wave propagation compare to ground wave propagation? A. It is much shorter. B. It is about the same. C. It depends on the weather. D. It is much longer. 42. The distance to Europe from your location is approximately 5000 km. What sort of propagation is most likely to be involved? A. sporadic E. B. back scatter. C. multihop. D. tropospheric scatter. 43. For radio signals, the skip distance is determined by the: A. power fed to the final. B. angle of radiation.

C. type of transmitting antenna used. D. height of ionosphere and angle of radiation. 44. The distance from the transmitter to the nearest point where the sky wave returns to earth is called the: A. skip zone. B. angle of radiation. C. skip distance. D. maximum usable frequency. 45. Skip distance is the: A. the minimum distance reached by a signal after one reflection by the ionosphere. B. The maximum distance reached by a signal after one reflection by the ionosphere. C. The maximum distance reached by a ground wave signal. D. The maximum distance a signal will travel by both a ground wave and reflected wave. 46. Skip distance is associated with signals from the ionosphere. Skip effects are due to: A. reflection and refraction from the ionosphere. B. selective fading of local signals. C. high gain antenna being used. D. local cloud cover. 47. The skip distance of a sky wave will be greatest when the: A. polarization is vertical. B. ionosphere is most densely ionized. C. angle between ground and radiation is smallest. D. signal given out is strongest. 48. If the height of the reflecting layer of the ionosphere increases, the skip distance of a high frequency (HF) transmission: A. stays the same. B. varies regularly. C. becomes greater. D. decreases. 49. What type of propagation usually occurs from one hand-held transceiver to another nearby? A. Tunnel propagation. B. Sky-wave propagation. C. Auroral propagation. D. Line-of-sight propagation. 50. That portion of the radiation kept close to the earth’s surface due to bending in the atmosphere is called the: A. inverted wave. B. ground wave.

C. tropospheric wave. D. ionospheric wave. 51. What effect does tropospheric bending have on 2-meter radio waves? A. It causes them to travel shorter distances. B. It garbles the signal. C. It reverses the sideband of the signal. D. It lets you contact stations further away. 52. How are VHF signals propagated within the range of the visible horizon? A. By direct wave. B. By sky wave. C. By plane wave. D. By geometric wave. 53. Excluding enhanced propagation modes, what is the approximate range of normal VHF tropospheric propagation? A. 2400 km (1500 miles). B. 800 km (500 miles). C. 3200 km (2000 miles). D. 1600 km (1000 miles). 54. What effect is responsible for propagating VHF signals over 800 km (500miles)? A. Faraday rotation. B. Tropospheric ducting. C. D-region absorption. D. Moon bounce. 55. What does maximum usable frequency mean? A. The lowest frequency signal that will reach its intended destination. B. The highest frequency that is most absorbed by the ionosphere. C. The lowest frequency that is most absorbed by the ionosphere. D. The highest frequency signal that will reach its intended destination. 56. What causes the maximum useable frequency to vary? A. The amount of radiation received from the sun, mainly ultraviolet. B. The temperature of the ionosphere. C. The speed of the winds in the upper atmosphere. D. The type of weather just below the ionosphere. 57. What happens to signals higher in frequency than the critical frequency? A. They pass through the ionosphere. B. They are absorbed by the ionosphere. C. Their frequency is changed by the ionosphere to be below the maximum useable frequency. D. They are reflected back to their source.

58. What is one way to determine if the maximum useable frequency (MUF) is high enough to support 28 MHz propagation between your station and western Europe? A. Listen for signals on the 10 meter beacon frequency. B. Listen for signals on the 20 meter beacon frequency. C. Listen for signals on the 39 meter broadcast frequency. D. Listen for WWVH time signals on 20 MHz. 59. What usually happens to radio waves with frequencies below the maximum useable frequency (MUF) when they are sent into the ionosphere? A. They are changed to a frequency above the MUF. B. They are completely absorbed by the ionosphere. C. They are bent back to the earth. D. They pass through the ionosphere. 60. If we transmit a signal, the frequency of which is so high we no longer receive a reflection from the ionosphere, the signal frequency is above the: A. skip distance. B. maximum useable frequency. C. speed of light. D. sunspot frequency. 61. The optimum working frequency provides the best long range HF communications. Compared with the maximum useable frequency (MUF), it is usually: A. double the MUF. B. Half the MUF. C. Slightly lower. D. Slightly higher. 62. What can be done at an amateur station to continue HF communications during a sudden ionospheric disturbance? A. Try a higher frequency. B. Try the other sideband. C. Try different antenna polarization. D. Try a different frequency shift. 63. The usual effect of an ionospheric storm is to: A. produce extreme weather changes. B. cause a fade-out of sky-wave signals. C. prevent communications by ground waves. D. increase the maximum usable frequency. 64. Two or more parts of the radio wave follow different paths during propagation and this may result in phase differences at the receiver. This change at the receiver is called: A. fading. B. baffling. C. absorption. D. skip.

65. A change or variation in the signal strength at the antenna, caused by differences in path length, is called: A. absorption. B. fluctuation. C. path loss. D. fading. 66. When a transmitted radio signal reaches a station by a one-hop and two-hop skip path, small changes in the ionosphere can cause: A. consistent fading of the received signal. B. consistently stronger signals. C. variation in signal strength. D. a change in the ground-wave signal. 67. What causes selective fading? A. Phase differences between the radio wave components of the same transmission, as experienced at the receiving station. B. Small changes in the beam heading at the receiving station. C. Time differences between the receiving and transmitting stations. D. Large changes in the height of the ionosphere at the receiving station ordinarily occurring shortly before sunrise and sunset. 68. Polarization change often takes place on radio waves that are propagated over long distances. Which of these do NOT cause polarization changes? A. Parabolic interaction. B. Reflections. C. Passage through magnetic fields (Faraday rotation). D. Refractions. 69. How does the bandwidth of a transmitted signal affect selective fading? A. It is the same for both wide and narrow bandwidths. B. It is more pronounced at wide bandwidths. C. Only the receiver bandwidth determines the selective fading effect. D. It is more pronounced at narrow bandwidths. 70. Reflection of a SSB transmission from the ionosphere causes: A. little or no phase-shift distortion. B. phase-shift distortion. C. signal cancellation at the receiver. D. a high-pitched squeal at the receiver. 71. On VHF and UHF bands, polarization of the receiving antenna is very important in relation to the transmitting antenna, yet on HF bands it is relatively unimportant. Why is that so? A. The ionosphere can change the polarization from moment to moment. B. The ground wave and the sky wave continually shift the polarization. C. Anomalies in the earth’s magnetic field produce a profound effect on HF polarization.

D. Greater selectivity is possible with HF receivers making changes in polarization redundant. 72. What causes tropospheric ducting of radio waves? A. Lightening between the transmitting and receiving stations. B. An aurora to the north. C. A temperature inversion. D. A very low-pressure area. 73. What is a sporadic E condition? A. Patches of high-density ionization at E region height. B. Partial tropospheric ducting at E region heights. C. Variations in E region heights caused by sunspot variations. D. A brief decrease in VHF signals caused by sunspot variations. 74. On which amateur frequency band is the extended-distance propagation effect of sporadic-E most often observed? A. 160 meters. B. 20 meters. C. 6 meters. D. 2 meters. 75. In the northern hemisphere, in which direction should a directional antenna be pointed to take maximum advantage of auroral propagation? A. East. B. North. C. West. D. South. 76. Where in the ionosphere does auroral activity occur? A. At F-region heights. B. At E-region heights. C. In the equatorial band. D. At D-region heights. 77. Which emission modes are best for auroral propagation? A. RTTY and AM. B. FM and CW. C. CW and SSB. D. SSB and FM. 78. If you received a weak, distorted signal from a distance, and close to the maximum usable frequency, what type of propagation is probably occurring? A. Ground wave. B. Line-of-sight. C. Scatter. D. Ducting.

79. What is the characteristic of HF scatter signals? A. Reversed modulation. B. A wavering sound. C. Reversed sidebands. D. High intelligibility. 80. What makes HF scatter signals often sound distorted? A. Energy scattered into the skip zone through several radio-wave paths. B. Auroral activity and changes in the earth's magnetic field. C. Propagation through ground waves that absorb much of the signal. D. The state of the E-region at the point of refraction. 81. Why are HF scatter signals so weak? A. Propagation through ground waves absorbs most of the signal energy. B. Only a small part of the signal energy is scattered into the skip zone. C. The F-region of the ionosphere absorbs most of the signal energy. D. Auroral activity absorbs most of the signal energy. 82. What type of radio propagation allows a signal to be detected at a distance too far for ground-wave propagation but too near for normal sky-wave propagation? A. Short-path skip. B. Sporadic-E skip. C. Ground wave. D. Scatter. 83. When does scatter propagation on the HF bands most often occur? A. When the sunspot cycle is at a minimum and D-region absorption is high. B. At night. C. When the F1 and F2 regions are combined. D. When communicating on frequencies above the maximum usable frequency (MUF). 84. Which of the following is NOT a scatter mode. A. Meteor scatter. B. Tropospheric scatter. C. Ionospheric scatter. D. Absorption scatter. 85. Meteor scatter is most effective on what band? A. 40 meters. B. 6 meters. C. 15 meters. D. 160 meters. 86. Which of the following is NOT a scatter mode? A. Side scatter. B. Back scatter.

C. Inverted scatter. D. Forward scatter. 87. In which frequency range is meteor scatter most effective for extended-range communications? A. 30-100 MHz. B. 10-30 MHz. C. 3-10MHz. D. 100-300MHz. 88. One megahertz is equal to: A. 1,000 kHz B. 100 kHz C. 0.001 Hz D. 10 Hz 89. If a dial marked in megahertz shows a reading of 3.525 MHz, what would it show if marked in kilohertz? A. 35.25 kHz. B. 3525 kHz. C. 3,525,000 kHz. D. 0.003525 kHz.

Answers to Chapter 6 Quiz 1

B

19

D

37

A

55

D

73

A

2

C

20

A

38

A

56

A

74

C

3

B

21

D

39

C

57

A

75

B

4

C

22

A

40

A

58

A

76

B

5

D

23

A

41

D

59

C

77

C

6

C

24

A

42

C

60

B

78

C

7

A

25

C

43

D

61

C

79

B

8

D

26

A

44

C

62

A

80

A

9

B

27

A

45

A

63

B

81

B

10

D

28

C

46

A

64

A

82

D

11

B

29

B

47

C

65

D

83

D

12

A

30

C

48

C

66

C

84

D

13

B

31

A

49

D

67

A

85

B

14

A

32

D

50

C

68

A

86

C

15

C

33

D

51

D

69

B

87

A

16

C

34

C

52

A

70

A

88

A

17

C

35

C

53

B

71

A

89

B

18

C

36

C

54

B

72

C

*

*