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.
29. Radio waves are made up of _____ and _____ fields.
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.