# Frenzel Self-test in Antennas and Transmission Lines

(Last Updated On: February 9, 2020)

This is the Self-test in Chapter 9: Antennas and Transmission Lines from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

### Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. The two basic types of transmission line are _____.

2. If one wire of a transmission line is connected to ground, the line is said to be _____.

3. The distance that a signal travels during one cycle is called the _____.

4. One wavelength that a frequency of 450 MHz is  _____ m.

5. A line 4 in. long represents one-half wavelength at a frequency of _____ GHz.

6. The physical dimensions of a transmission line determine its _____.

7. To a generator, a transmission line looks like a(n) _____ made up of distributed _____ and _____.

8. A coax line has a shield braid with an inside diameter of 0.2 in. and a center conductor with a diameter of 0.057 in. The characteristic impedance is _____ .

9. The attenuation of 250 ft of RG-11U coax at 100 MHz is _____ dB. (SeeFig.9-7) (page 211-Frenzel)

10. For optimum transfer of power from a generator to a load of 52, the transmission line impedance should be _____ .

11. The current and voltage along a properly matched line are _____.

12. If a transmission line is not terminated in its characteristic impedance, _____ will develop along the line

13. If a load and line have mismatched impedances, power not absorbed by the load will be _____.

14. Patterns of voltage and current variations along, a transmission line with a mismatched load are known as _____.

15. A 52- coax bas a 36- antenna load. The SWR is _____.

16. If the load and line impedances are matched, the SWR will be _____.

17. All incident power on a line will be reflected if the line is _____ or _____ at its end.

18. The ratio of the reflected voltage to the incident voltage on a transmission line is called the _____.

19. The maximum voltage along a transmission line is 150V, and the minimum voltage is 90V. The SWR is _____.The reflection coefficient is _____.

20. The reflection coefficient of a transmission line is 0.75. The SWR is _____.

21. An open or shorted transmission line will have a reflection coefficient of _____ and an SWR of _____.

22. Transmission lines, one-quarter or one haIf wavelength can be used as _____.

23. A transmission line bas an SWR of 1.75. The power applied to the line, is 90 W. The amount of reflected power is _____ W.

24. A shorted quarter-wave line looks like a(n) _____ impedance to the generator.

25. The following lines look like a series resonant circuit: a _____ /4 line; a _____ /2 line.

26. Transmission lines less than /4 or between /4 and /2 act like _____ or _____.

27. An open transmission line 6 in. long acts as a _____ resonant circuit at a frequency of 492 MHz.

28. A coax bas a velocity factor of 0.68. One half wavelength of this coax at 120 MHz is _____ ft long.

30. The polarization of a radio wave depends upon the position of its _____ with respect to the earth’s surface.

31. The antenna is connected to the transmitter or receiver by a(n) _____.

32. A radio wave has its magnetic field horizontal to the earth. It is, therefore, _____ polarized.

33. One of the most widely used and simplest antennas is the half-wave _____.

34. The length of a doublet antenna at 150 MHz is _____ ft.

35. The feed impedance of a dipole antenna is approximately, _____ .

36. The horizontal radiation pattern of a dipole looks like a(n) _____.

37. The measure of an antenna’s directivity is _____.

38. An antenna that radiates equally well in all horizontal directions is said to be _____.

39. A quarter-wave vertical antenna is commonly known as a(n) _____ antenna.

40. The length of a quarter-wave vertical antenna at 890 MHz is _____ in.

41. For proper operation of a vertical antenna, the shield of the feed coax must make a good connection to _____ or a set of quarter-wave wires called _____.

42. The horizontal radiation pattern of a quarter-wave vertical is a(n) _____.

43. The feed impedance of a quarter-wave vertical is approximately _____ .

44. An antenna that transmits or receives equally well in two opposite directions is said to be _____.

45. A unidirectional antenna transmits best in _____ direction(s).

46. A directional antenna that focuses the energy into a narrow beam has _____ since it effectively amplifies the signal.

47. To have gain and directivity, an antenna must have two or more _____.

48. List two basic types of antenna arrays.

49. The three basic elements in a Yagi antenna are _____.

50. The two parasitic elements in a beam antenna are the _____.

51. A Yagi may have one or more _____ elements.

52. The beam width of a Yagi is usually in the range of _____ to _____ degrees.

53. The length of the driven element in a Yagi at 222 MHz is _____ ft.

54. List three kinds of driven arrays.

55. True or false. Yagis and driven arrays may be operated either horizontally or vertically.

56. A popular wideband driven array is the _____ array.

57. An impedance-matching circuit used to make the antenna, transmission line, and transmitter impedances match is the _____.

58. A transformer used for impedance matching is the _____.

59. A quarter-wavelength section of transmission line used for impedance matching is called a(n) _____.

60. A coax balun has an impedance-matching ratio of _____.

61. A quarter-wavelength of coax with a velocity factor of 0.7 at 220 MHz is _____ in.

62. List the three paths that a radio signal may take through space.

63. A radio wave that propagates near the surface of the earth is called a(n) _____ or _____ wave.

64. The radio wave that is refracted by the ionosphere is known as a(n) _____ wave.

65. A radio wave that propagates only over line-of-sight distances is called a(n) _____ or _____ wave.

66. The surface wave is effective only at frequencies below about _____ MHz.

67. The upper part of the earth’s atmosphere ionized by the sun that affects radio waves is called the _____.

68. The _____ layer has the greatest effect on a radio signal.

69. The ionized atmosphere causes radio waves at some frequencies to be _____.

70. True or false. Radio waves are easily reflected by large objects.

71. True or false. The ionosphere reflects radio waves.

72. Only signals in the _____ to _____ MHz range are significantly affected by the ionosphere.

73. Worldwide radio communications is possible thanks to _____ transmission.

74. The VHF, UHF, and microwave signals travel in a(n) _____.

75. To increase transmission distances at VHF and above, special stations called are _____ used.

76. A microwave relay station contains a(n) _____ and a(n) _____ operating on different frequencies.

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