WorksheetsCHAPTER 3 TRANSLINE
Total questions: 104
Worksheet time: 52mins
Name
Class
Date
1.
1. What happens when the impedance of an electrical load is equal to the Internal Impedance of the power source?
a)
a. the electrical load is shorted
b)
b. the source delivers maximum power to the load
c)
c. current can flow through the circuit
d)
d. the source delivers minimum power to the load
2.
2. Determine the impedance of an infinitely long section of a particular Cable having a capacitance of
a)
a. 35 ohms
b)
c. 20 ohms
c)
b. 140 ohms
d)
d. 300 ohms
3.
3. What is the primary advantage of a rigid coaxial line?
a)
a. low radiation losses
b)
b. inexpensive construction
c)
c. low high-frequency losses
d)
d. each of the above
4.
4. What is the major factor that makes coaxial-cable less susceptible to noise than twisted-pair cable?
a)
a. inner conductor
b)
b. diameter of cable
c)
c. outer conductor
d)
d. insulating material
5.
5. Why is impedance matching important?
a)
a. so the load will draw minimum power from the source
b)
b. to ensure that there is less resistance than reactance in the circuit
c)
c. to ensure that the resistance and reactance in the circuit are equal
d)
d. so the source can deliver maximum power to the load
6.
6. In twisted pair cables, as the number of twists decreases, the capacity:
a)
a. Increases
b)
c. unchanged
c)
b. Decreases
d)
d. doubles
7.
7. As frequency increases, the loss in a cable's dielectric:
a)
a. increases
b)
b. decreases
c)
c. stays the same
d)
d. there is no loss in a dielectric
8.
8. To obtain efficient power transmission from a transmitter to an antenna requires:
a)
a. High load impedance
b)
b. Low ohmic resistance
c)
c. Matching of impedance
d)
d. Inductive impedance
9.
9. The characteristic impedance of a cable depends on:
a)
a. the resistance per foot of the wire used
b)
b. the resistance per foot and the Inductance per foot
c)
c. the resistance per foot and the capacitance per foot
d)
d. the inductance per foot and the capacitance per foot
10.
10. The term "balance line" means that:
a)
a. both conductors carry currents that flow in opposite directors
b)
b. conductors present equal capacitance to ground
c)
c. one conductor is connected to ground
d)
d. A and B above
11.
11. What transmission-line loss is caused by magnetic lines of force not returning to the conductor?
a)
a. copper
b)
c. induction
c)
b. radiation
d)
d. dielectric
12.
12. If an antenna is correctly matched to a transmitter , the length of transmission line:
a)
a. must be a full wavelength long
b)
b. must be an odd number of quarter-wave
c)
c. must be an even number of half-waves
d)
d. will have no effect on the matching
13.
13. When sending power down a transmission line, it is usually desirable that as much power as possible will be absorbed by the load and as little as possible will be reflected back to the source. A negative voltage pulse sent down a transmission line terminated with its characteristic impedance:
a)
a. would reflect as a positive pulse
b)
b. would reflect as negative pulse
c)
c. would reflect as a positive pulse followed by a negative pulse
d)
d. would not reflect at all
14.
14. The characteristic impedance of a cable:
a)
a. increases with length
b)
b. increases with frequency
c)
c. increases with voltage
d)
d. none of the above
15.
15. The conductance value of a transmission line represents which of the following values?
a)
a. expected value of current flow through the insulation
b)
b. expected value of voltage supplied by the transmitter
c)
c. value of the lump and distributed constants of the line divided by impedance
d)
d. all of these
16.
16. The reason that in BF transmission line should be matched at the transmitter end is to:
a)
a. ensure that the radiated signal has the intended polarization
b)
b. transfer the maximum amount of power to the antenna
c)
c. prevent frequency drift
d)
d. overcome fading of the transmitted signal
17.
17. In a transmission line:
a)
a. if the load impedance is greater than the line characteristic impedance, the reflection coefficient is negative
b)
b. if the load impedance is lesser than the line characteristic impedance, the reflection coefficient is negative
c)
c. if the load impedance is equal to the line characteristic impedance, the reflection coefficient is equal to 1
d)
d. if the load impedance is equal to the line characteristic impedance, the reflection coefficient will be maximum
18.
18. The ratio of maximum voltage to minimum voltage on a transmission line is referred to as the:
a)
a. RSWR
b)
c. VSWR
c)
b. PSWR
d)
d. ISWR
19.
19. What is an unbalanced line?
a)
a. feed line with neither conductor connected to ground
b)
b. feed line with both conductors connected to ground
c)
c. feed line with both conductors connected to each other
d)
d. feed line with one conductor connected to ground
20.
20. The most desirable reflection coefficient is:
a)
a. 0
b)
c. 1
c)
b. 0.5
d)
d. infinity
21.
21. Which of the following ratios samples the magnetic field along a line?
a)
A. VSWR
b)
c. ISWR
c)
B. PSWR
d)
d. RSWR
22.
22. If the load impedance is equal to line characteristic impedance, which of the following can you observe?
a)
a. there is maximum power transfer
b)
b. the reflection coefficient is zero
c)
c. the standing wave ratio is equal to 1
d)
d. all of the given choices can be observed
23.
23. A positive voltage pulse sent down a transmission line terminated in a short-circuit:
a)
a. would reflect as a positive pulse
b)
b. would reflect as a negative pulse
c)
c. would reflect as a positive pulse followed by a negative pulse
d)
d. would not reflect at all
24.
24. Leakage current in a two-wire transmission line is the current that flows through what component?
a)
a. the resistor
b)
c. the insulator
c)
b. the inductor
d)
d. the conductor
25.
25. If your transmitter and antenna are
a)
a. shorten the excess cable so the feed line is an odd number of wavelengths long
b)
b. shorten the excess cable
c)
C. roll the excess cable into a coil which is as small as possible
d)
c. shorten the excess cable so the feed line is an even number of wavelengths long
26.
26. A positive voltage pulse sent down a transmission line terminated with its characteristic impedance:
a)
a. would reflect as a positive pulse
b)
b. would reflect as a negative pulse
c)
c. would reflect as a positive pulse followed by a negative pulse
d)
d. would not reflect at all
27.
27. A transmission line that has current flowing through it has which, if any, of the following fields about it?
a)
a. electric field only
b)
b. magnetic field only
c)
c. both electric and magnetic fields
d)
d. none of the above
28.
28. What connects your transceiver to your antenna?
a)
a. the power cord
b)
b. a ground wire
c)
c. a feed line
d)
d. a dummy load
29.
29. A positive voltage-pulse sent down a transmission line terminated in an open-circuit:
a)
a. would reflect as a positive pulse
b)
b. would reflect as a negative pulse
c)
c. would reflect as a positive pulse followed by a negative pulse
d)
d. would not reflect at all
30.
30. Maximum transfer of energy from the source to the transmission line takes place when what impedance relationship exists between the and the transmission line?
a)
a. when the load impedance equals source impedance
b)
b. when the load impedance is twice the source impedance
c)
c. when the load impedance is half the source impedance
d)
d. when the load impedance is one-fourth the source impedance
31.
31. The characteristic impedance of a transmission line is determined by the:
a)
a. length of the line
b)
b. physical dimensions and relative positions of the conductors
c)
c. frequency at which the line is operated
d)
d. load placed on the line
32.
32. The optimum value for SWR is:
a)
a. zero
b)
b. one
c)
c. as large as possible
d)
d. there is no optimum value
33.
33. For a given voltage, what determines the amount of current that will flow in a transmission line?
a)
a. conductance
b)
b. spacing of the wires
c)
c. diameter of the wires
d)
d. characteristic impedance
34.
34. The characteristic impedance of a 20 meter piece of transmission line is 52 ohms. If 10 metres were cut odd, the impedance would:
a)
a. 52 ohms
b)
c. 39 ohms
c)
b. 26 ohms
d)
d. 13 ohms
35.
35. A non-optimum value for SWR will cause:
a)
a. standing waves
b)
b. loss of power to load
c)
c. higher voltage peaks on cable
d)
d. all of the above
36.
36. When the impedance of a transmission line is measured, which of the following values frequently is not considered?
a)
a. Inductance
b)
c. conductance
c)
b. Resistance
d)
d. capacitance
37.
37. The impedance of a coaxial line:
a)
a. can be the same for different diameter line
b)
b. changes with the frequency of the energy it carries
c)
c. is correct for only one size of line
d)
d. is greater for larger diameter line
38.
38. When should lumped values for transmission-line constants be used to calculate characteristic impedance?
a)
a. when the line is short compared to one wavelength
b)
b. when the line is long compared to one wavelength
c)
c. when the line is infinitely long
d)
d. none of these
39.
39. The characteristic impedance of a transmission line is:
a)
a. the impedance of a section of the line one wavelength long
b)
b. the dynamic impedance of the line at the operating frequency
c)
c. the ratio of the power supplied to the line to the power delivered to the termination
d)
d. equal to the pure resistance which, if connected to the end of the line, will absorb all the power arriving along it
40.
40. When a dc voltage is applied to a transmission line and the load absorbs all the energy , what is the resulting relationship between current and voltage?
a)
a. they are in phase with each other
b)
b. they are equal to Zo of the line
c)
c. they are out of phase with each other
d)
d. they are evenly distributed along the line
41.
41. A transmission line differs from an ordinary circuit or network in communications or signaling devices in one very important way. That important aspect is:
a)
a. capacitive reactance
b)
b. inductive reactance
c)
c. propagation delay
d)
d. resistance
42.
42. The velocity of propagation on a transmission line is controlled by which of the following line characteristics?
a)
a. conductance
b)
b. inductance only
c)
c. capacitance only
d)
d. capacitance and inductance
43.
43. The characteristic impedance of a parallel wire transmission line does not depend on the:
a)
a. velocity of energy on the line
b)
b. radius of the conductors
c)
c. centre to centre distance between conductors
d)
d. dielectric
44.
44. Compared to a 300-ohm line, the loss of a 50-ohm cable carrying the same power:
a)
a. would be less
b)
b. would be more
c)
c. would be the same
d)
d. cannot be compared
45.
45. The characteristic impedance for an infinite transmission line can be figured using which of the following ratios?
a)
a. input current to velocity
b)
b. input voltage to input current
c)
c. input voltage to line resistance
d)
d. input current to line resistance
46.
46. Any length of transmission line may be made to appear as an infinitely long line by:
a)
a. terminating the line in its characteristic impedance
b)
b. leaving the line open at the end
c)
c. shorting the line at the end
d)
d. increasing the standing wave ratio above unity
47.
47. When a transmission line is not terminated in its characteristic impedance (Zo), what happens to the incident energy that is not transferred to the load?
a)
a. it is returned along the transmission line
b)
b. it is radiated into space
c)
c. it is absorbed by the line
d)
d. it is converted to heat energy
48.
48. What factors determine the characteristic impedance of a parallel- conductor antenna feed line?
a)
a. the distance between the centres of the conductors and the radius of the conductors
b)
b. the distance between the centres of the conductors and the length of the line
c)
c. the radius of the conductors and the frequency of the signal
d)
d. the frequency of the signal and the length of the line
49.
49. The radius of the circle you draw on a Smith chart represents:
a)
a. the voltage
b)
c. the impedance
c)
b. the current
d)
d. none of the above
50.
50. What factors determine the characteristic impedance of a coaxial antenna feed line?
a)
a. the ratio of the diameter of the inner conductor to the diameter of the braid
b)
b. the diameter of the braid and the length of the line
c)
c. the diameter of the braid and the frequency of the signal
d)
d. the frequency of the signal and the length of the line
51.
51. The center of the Smith chart always represents:
a)
A. zero
b)
B. one
c)
c. the characteristic impedance
d)
d. none of the above
52.
52. The resultant of the incident and reflected voltage waves is called the standing wave. Its value is figured by using which of the following procedures?
a)
a. adding the effective values of the two waveforms
b)
b. algebraically adding the instantaneous values of the two waveforms
c)
c. algebraically subtracting the instantaneous values of the two waveforms
d)
d. taking the square root of the product of the incident and reflected voltages
53.
53. As the length of a feed line is changed, what happens to signal loss?
a)
a. signal loss decreases as length increases
b)
b. signal loss increases as length increases
c)
c. signal loss is the least when the length is the same as the signal's wavelength
d)
d. signal loss is the same for any length of feed line
54.
54. A TDR is used to:
a)
a. measure the characteristic impedance of a cable
b)
b. find the position of a defect in a cable
c)
c. replace a slotted-line
d)
d. all of above
55.
55. On an open-ended transmission line, what is the phase relationship between the standing waves of voltage and current?
a)
a. in phase
b)
b. 45 degrees out of phase
c)
c. 90 degrees out of phase
d)
d. 180 degrees out of phase
56.
56. As the frequency of a signal is changed, what happens to signal loss in a feed line?
a)
a. signal loss increases with decreasing frequency
b)
b. signal loss increases with increasing frequency
c)
c. signal loss is the least when the signal's wavelength is the same as the feed line's length
d)
d. signal loss is the same for any frequency
57.
57. "Skin effect" refers to:
a)
a. the way radio signals travel across a flat surface
b)
b. the tissue-burning effect of a strong RF signal
c)
c. the increase of wire resistance with frequency
d)
d. none of the above
58.
58. Which of the following conditions exist at the end of a shorted transmission line?
a)
a. maximum voltage and minimum current
b)
b. maximum voltage and maximum current
c)
c. minimum voltage and maximum current
d)
d. minimum voltage and minimum current
59.
59. Losses occurring on a transmission line between transmitter and antenna results in:
a)
a. an SWR reading of 1:1
b)
b. less RF power being radiated
c)
c. reflections occurring in the line
d)
d. the wire radiating RF energy
60.
60. Compared to twisted-pair telephone cables, CAT-
a)
a. are cheaper
b)
b. are easier to crimp connectors onto
c)
c. allow faster bit rates
d)
d. all of the above
61.
61. Transmission line is considered to be non resonant (flat) when it is terminated in which of the following ways?
a)
a. in an impedance equal to Zo
b)
b. in an impedance that is infinite
c)
c. in an inductive reactance greater than Zo
d)
d. in a capacitive reactance greater than Zo
62.
62. The lowest loss feed line on HF is:
a)
a. open-wire
b)
b. 75 ohm twin-lead
c)
c. coaxial cable
d)
d. 300 ohm twin-lead
63.
63. The most commonly used transmission line is a:
a)
a. two-wire balance line
b)
b. single wire
c)
c. three wire line
d)
d. coax
64.
64. A short-circuited section of transmission that is an odd number of quarter wavelengths long shows the same characteristics as which of the following devices?
a)
a. a series-resonant circuit
b)
b. a parallel-resonant circuit
c)
c. an inductive reactance equal to Zo
d)
d. a capacitive reactance equal to Zo
65.
65. In what values are RF feed line losses expressed?
a)
a. Ohms per MHz
b)
c. ohms per metre
c)
b. dB per MHz
d)
d. dB per unit length
66.
66. The characteristic impedance of a transmission line is determined by:
a)
a. its operating frequency
b)
b. its length
c)
c. its physical size and arrangement
d)
d. the signal applied at the input terminal
67.
67. A transmission line is designed to perform which of the following functions?
a)
a. disperse energy in all directions
b)
b. detune a transmitter to match the load
c)
c. guide electrical energy from point to point
d)
d. replace the antenna in a communications system
68.
68. An SWR meter measures the degree of match between transmission line and antenna by:
a)
a. comparing forward and reflected voltage
b)
b. measuring radiated RF energy
c)
c. measuring the conductor temperature
d)
d. inserting a diode in the feed line
69.
69. velocity factor of a transmission line:
a)
a. depends on the dielectric constant of the material used
b)
b. increases in velocity along the transmission line
c)
c. is governed by the skin effect
d)
d. is higher for a solid dielectric than for air
70.
70. All transmission lines must have two ends, the input end and the output end. What other name is given to the input end?
a)
a. sending end
b)
b. generator end
c)
c. transmitter end
d)
d. each of the above
71.
71. What would you use to connect a coaxial cable of 50 ohms impedance to an antenna of 35 ohms impedance?
a)
a. an SWR meter
b)
b. an impedance-matching device
c)
c. a low pass filter
d)
d. a terminating resistor
72.
72. The characteristic impedance of a transmission line does not depend on its:
a)
a. length
b)
b. conductor spacing
c)
c. conductor diameter
d)
d. dielectric constant
73.
73. when analyzing a transmission line, its inductance and capacitance are considered to be:
a)
a. lumped
b)
c. equal reactances
c)
b. distributed
d)
d. ideal elements
74.
74. Electrical power lines are most often made of which of the following types of transmission:
a)
a. twin-lead line
b)
b. shielded-pair line
c)
c. two-wire open line
d)
d.two-wire ribbon line
75.
75. When will a power source deliver maximum output to the load?
a)
a. when air wound transformers are used instead of iron core
b)
b. transformers when the power-supply fuse rating equals the primary winding current
c)
c. when the impedance of the load is equal to the impedance of the source
d)
d. when the load resistance is infinite
76.
76. The behavior of a transmission line depends on:
a)
a. length & termination
b)
b. length & impedance
c)
c. impedance & termination
d)
d. impedance only
77.
77. As frequency increases, the resistance of a wire:
a)
a. increases
b)
c. stays the same
c)
b. decreases
d)
d. changes periodically
78.
78. Uniform capacitance the length of the line is an advantage of which of the following transmission lines?
a)
a. coaxial line
b)
b. twisted pair
c)
c. shielded pair
d)
d. two-wire open line
79.
79. In an environment with many high-voltage devices, the best transmission medium would be:
a)
a. twisted-pair cable
b)
c. optical cable
c)
b. coaxial cable
d)
d. the atmosphere
80.
80. Which of the following sections of transmission line can be used as a parallel resonant circuit?
a)
a. a shorted 1/4-wavelength section
b)
b. an open 1/4-wavelength section
c)
c. a shorted 1/2-wavelength section
d)
d. an open 3/4-wavelength section
81.
81. What is a coaxial cable?
a)
a. two wires side-by-side in a plastic ribbon
b)
b. two wires side-by-side held apart by insulating rods
c)
c. two wires twisted around each other in a spiral
d)
d. a center wire inside an insulating material which is covered by a metal sleeve or shield
82.
82. Which of the following is not a common transmission line impedance?
a)
a. 50 ohms
b)
c. 120 ohms
c)
b. 75 ohms
d)
d. 300 ohms
83.
83. What is parallel-conductor feed line?
a)
a. two wires twisted around each other in a spiral
b)
b. a center wire inside an insulating material which is covered by a metal sleeve or shield
c)
c. a metal pipe which is as wide or slightly wider than a wavelength of the signal it carries
d)
d. two wires side-by-side held apart by insulating rods
84.
84. For maximum absorption of power at the antenna, the between the characteristic impedance of the line Zo and the load impedance ZL should be:
a)
a. Zo = ZL
b)
c. Zo
c)
b. Zo > ZL
d)
d. Zo=0
85.
85. Which of the following conditions of current ( 1) and impedance (Z) exist at even quarter-wave points on a shorted transmission line?
a)
a. low I, low Z
b)
b. low 1, high Z
c)
c. high I, high Z
d)
d. high I, low Z
86.
86. The mismatch between antenna and transmission line impedances cannot be corrected for by:
a)
a. using an LC matching network
b)
b. adjusting antenna length
c)
c. using a balun
d)
d. adjusting the length of transmission line
87.
87. When a line is terminated in a capacitance, the capacitor performs which, if any, of the following circuit actions?
a)
a. it absorbs all the energy
b)
b. it reflects all the energy
c)
c. it reacts as if it were a short
d)
d. none
88.
88. Where would you install a balun to feed a dipole antenna with 50 ohm coaxial cable?
a)
a. between the coaxial cable and the antenna
b)
b. between the transmitter and the coaxial cable
c)
c. between the antenna and the ground
d)
d. between the coaxial cable and the ground
89.
89. On a transmission line, reflections begin at which of the following locations?
a)
a. at the load
b)
b. at the source
c)
c. at the middle
d)
d. at the half-wavelength point
90.
90. A flexible coaxial line contains:
a)
a. four or more conductors running parallel
b)
b. only one conductor
c)
c. braid and insulation around a central conductor
d)
d. two parallel conductors separated by spacers
91.
91. At very high frequencies, transmission lines are used as:
a)
a. tuned circuits
b)
c. insulators
c)
b. antennas
d)
d. resistors
92.
92. A shorted quarter wave line at the operating frequency acts like a(n):
a)
a. series resonant circuit
b)
b. parallel resonant circuit
c)
c. capacitor
d)
d. inductor
93.
93. A 75 ohm transmission line could be matched to the 300 ohm feed point of an antenna:
a)
a. with an extra 250 ohm resistor
b)
b. by using a 4 to 1 balun
c)
c. by using a 4 to 1 trigatron
d)
d. by inserting a diode in one leg of the antenna
94.
94. A shorted half wave line at the operating frequency acts like a(n):
a)
a. capacitor
b)
c. series resonant circuit
c)
b. inductor
d)
d. parallel resonant circuit
95.
95. What does standing-wave ratio mean?
a)
a. the ratio of maximum to minimum voltages on a feed line
b)
b. the ratio of maximum to minimum inductances on a feed line
c)
c. the ratio of maximum to minimum resistances on a feed line
d)
d. the ratio of maximum to minimum impedances on a feed line
96.
96. Which transmission line has the lowest attenuation?
a)
a. twin lead
b)
c. RG-59/U
c)
b. RG-11/U
d)
d. RG-214/U
97.
97. If the characteristic impedance of the feedline does not match the antenna input impedance then:
a)
a. heat is produced at the junction
b)
b. the SWR reading falls to 1:1
c)
c. the antenna will not radiate any signal
d)
d. standing waves are produced in the feedline
98.
98. The result of the presence of standing waves on a transmission line is:
a)
a. perfect impedance match between transmitter and feedline
b)
b. maximum transfer of energy to the antenna from the transmitter
c)
c. lack of radiation from the transmission line
d)
d. reduced transfer of RF energy to the antenna
99.
99. Category 1 UTP cable is most often used in networks
a)
a. fast Ethernet
b)
c. infrared
c)
b. traditional Ethernet
d)
d. telephone
100.
100. If the frequency is increased, how would this affect the loss on a transmission line?
a)
a. It is independent of frequency
b)
b. It would increase
c)
c. It depends on the line length
d)
d. It would decrease
101.
101. What does an SWR reading of 1:1 mean?
a)
a. the best impedance match has been attained
b)
b. an antenna for another frequency band is probably connected
c)
c. no power is going to the antenna
d)
d. the SWR meter is broken
102.
102. What does an SWR reading of less than 1.5:1 mean?
a)
a. a fairly good impedance match
b)
b. an impedance match which is too low
c)
c. an impedance mismatch; something may be wrong with the antenna system
d)
d. an antenna gain of
103.
103. The velocity factor of a cable depends mostly on:
a)
a. the wire resistance
b)
b. the dielectric constant
c)
c. the inductance per foot
d)
d. all of the above
104.
104. Electrical constants in a transmission line are distributed in which of following ways?
a)
a. into a single device
b)
b. along the length of the line
c)
c. according to the thickness of the line
d)
d. according to the cross-sectional area of the line CHAPTER 3&4: TRANSLINE AND ANTENNA (SOLVING)
100 %
