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GMDSS · 605 questions

Element 3 - USCG Exam Questions

General radiotelephone operator knowledge: radio law and regulations, operating procedures, and radio equipment fundamentals.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

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All Element 3 questions

Questions 301–400 of 605 · page 4 of 7

  1. #301 How can ferrite beads be used to suppress ignition noise? Install them:
  2. #302 What is the term used to refer to the condition where the signals from a very strong station are superimposed on other signals being received?
  3. #303 What is cross-modulation interference?
  4. #304 In Figure 3F15 at what point in the circuit (labeled 1 through 4) could a DC voltmeter be used to monitor signal strength? illustration
  5. #305 Pulse type interference to automobile radio receivers that appears related to the speed of the engine can often be reduced by:
  6. #306 What class of amplifier is distinguished by the presence of output throughout the entire signal cycle and the input never goes into the cutoff region?
  7. #307 What is the distinguishing feature of a Class A amplifier?
  8. #308 Which class of amplifier has the highest linearity and least distortion?
  9. #309 Which class of amplifier provides the highest efficiency?
  10. #310 What class of amplifier is distinguished by the bias being set well beyond cutoff?
  11. #311 Which class of amplifier has an operating angle of more than 180 degrees but less than 360 degrees when driven by a sine wave signal?
  12. #312 The class B amplifier output is present for what portion of the input cycle?
  13. #313 What input-amplitude parameter is most valuable in evaluating the signal-handling capability of a Class A amplifier?
  14. #314 The class C amplifier output is present for what portion of the input cycle?
  15. #315 What is the approximate DC input power to a Class AB RF power amplifier stage in an unmodulated carrier transmitter when the PEP output power is 500 w...
  16. #316 The class AB amplifier output is present for what portion of the input cycle?
  17. #317 What class of amplifier is characterized by conduction for 180 degrees of the input wave?
  18. #318 What is the modulation index in an FM phone signal having a maximum frequency deviation of 3,000 Hz on either side of the carrier frequency when the m...
  19. #319 What is the modulation index of a FM phone transmitter producing a maximum carrier deviation of 6 kHz when modulated with a 2 kHz modulating frequency...
  20. #320 What is the total bandwidth of a FM phone transmission having a 5 kHz deviation and a 3 kHz modulating frequency?
  21. #321 How does the modulation index of a phase-modulated emission vary with RF carrier frequency?
  22. #322 How can a single-sideband phone signal be generated?
  23. #323 What is a balanced modulator?
  24. #324 What is an L-network?
  25. #325 What is a pi-network?
  26. #326 What is the resonant frequency in an electrical circuit?
  27. #327 Which three network types are commonly used to match an amplifying device to a transmission line?
  28. #328 What is a pi-L network?
  29. #329 Which network provides the greatest harmonic suppression?
  30. #330 What will occur when a non-linear amplifier is used with a single-sideband phone transmitter?
  31. #331 To produce a single-sideband suppressed carrier transmission it is necessary to ____ the carrier and to ____ the unwanted sideband.
  32. #332 In a single-sideband phone signal, what determines the PEP-to-average power ratio?
  33. #333 What is the approximate ratio of peak envelope power to average power during normal voice modulation peak in a single-sideband phone signal?
  34. #334 What is the output peak envelope power from a transmitter as measured on an oscilloscope showing 200 volts peak-to-peak across a 50-ohm load resistor?
  35. #335 What would be the voltage across a 50-ohm dummy load dissipating 1,200 watts?
  36. #336 How can intermodulation interference between two transmitters in close proximity often be reduced or eliminated?
  37. #337 How can parasitic oscillations be eliminated in a power amplifier?
  38. #338 What is the name of the condition that occurs when the signals of two transmitters in close proximity mix together in one or both of their final ampli...
  39. #339 What term describes a wide-bandwidth communications system in which the RF carrier varies according to some pre-determined sequence?
  40. #340 How can even-order harmonics be reduced or prevented in transmitter amplifier design?
  41. #341 What is the modulation type that can be a frequency hopping of one carrier or multiple simultaneous carriers?
  42. #342 The deviation ratio is the:
  43. #343 What is the deviation ratio for an FM phone signal having a maximum frequency deviation of plus or minus 5 kHz and accepting a maximum modulation rate...
  44. #344 What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz and accepting a maximum modulation rate of...
  45. #345 How can an FM-phone signal be produced in a transmitter?
  46. #346 What is meant by the term modulation index?
  47. #347 In an FM-phone signal, what is the term for the maximum deviation from the carrier frequency divided by the maximum audio modulating frequency?
  48. #348 In Figure 3H17, the block labeled 4 would indicate that this schematic is most likely a/an: illustration
  49. #349 In Figure 3H17, which block diagram symbol (labeled 1 through 4) represents where audio intelligence is inserted? illustration
  50. #350 What kind of input signal could be used to test the amplitude linearity of a single-sideband phone transmitter while viewing the output on an oscillos...
  51. #351 What does a two-tone test illustrate on an oscilloscope?
  52. #352 How can a double-sideband phone signal be produced?
  53. #353 What type of signals are used to conduct an SSB two-tone test?
  54. #354 What is an important factor in pulse-code modulation using time-division multiplex?
  55. #355 In a pulse-width modulation system, what parameter does the modulating signal vary?
  56. #356 What is the name of the type of modulation in which the modulating signal varies the duration of the transmitted pulse?
  57. #357 Which of the following best describes a pulse modulation system?
  58. #358 In a pulse-position modulation system, what parameter does the modulating signal vary?
  59. #359 What is one way that voice is transmitted in a pulse-width modulation system?
  60. #360 When a lead-acid storage battery is being charged, a harmful effect to humans is:
  61. #361 A battery with a terminal voltage of 12.5 volts is to be trickle-charged at a 0.5 A rate. What resistance should be connected in series with the batte...
  62. #362 What capacity in amperes does a storage battery need to be in order to operate a 50 watt transmitter for 6 hours? Assume a continuous transmitter load...
  63. #363 What is the total voltage when 12 Nickel-Cadmium batteries are connected in series?
  64. #364 The average fully-charged voltage of a lead-acid storage cell is:
  65. #365 A nickel-cadmium cell has an operating voltage of about:
  66. #366 When an emergency transmitter uses 325 watts and a receiver uses 50 watts, how many hours can a 12.6 volt, 55 ampere-hour battery supply full power to...
  67. #367 What current will flow in a 6 volt storage battery with an internal resistance of 0.01 ohms, when a 3-watt, 6-volt lamp is connected?
  68. #368 A ship RADAR unit uses 315 watts and a radio uses 50 watts. If the equipment is connected to a 50 ampere-hour battery rated at 12.6 volts, how long wi...
  69. #369 If a marine radiotelephone receiver uses 75 watts of power and a transmitter uses 325 watts, how long can they both operate before discharging a 50 am...
  70. #370 A 6 volt battery with 1.2 ohms internal resistance is connected across two light bulbs in parallel whose resistance is 12 ohms each. What is the curre...
  71. #371 A 12.6 volt, 8 ampere-hour battery is supplying power to a receiver that uses 50 watts and a RADAR system that uses 300 watts. How long will the batte...
  72. #372 What occurs if the load is removed from an operating series DC motor?
  73. #373 If a shunt motor running with a load has its shunt field opened, how would this affect the speed of the motor?
  74. #374 The expression voltage regulation" as it applies to a shunt-wound DC generator operating at a constant frequency refers to:"
  75. #375 What is the line current of a 7 horsepower motor operating on 120 volts at full load, a power factor of 0.8, and 95% efficient?
  76. #376 A 3 horsepower, 100 V DC motor is 85% efficient when developing its rated output. What is the current?
  77. #377 The output of a separately-excited AC generator running at a constant speed can be controlled by:
  78. #378 Which of the following could cause a high standing wave ratio on a transmission line?
  79. #379 Why is the value of the radiation resistance of an antenna important?
  80. #380 A radio frequency device that allows RF energy to pass through in one direction with very little loss but absorbs RF power in the opposite direction i...
  81. #381 What is an advantage of using a trap antenna?
  82. #382 What is meant by the term radiation resistance of an antenna?
  83. #383 What is meant by the term antenna bandwidth?
  84. #384 What is the current flowing through a 52 ohm line with an input of 1,872 watts?
  85. #385 The voltage produced in a receiving antenna is:
  86. #386 Which of the following represents the best standing wave ratio (SWR)?
  87. #387 At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna?
  88. #388 An antenna radiates a primary signal of 500 watts output. If there is a 2nd harmonic output of 0.5 watt, what attenuation of the 2nd harmonic has occu...
  89. #389 There is an improper impedance match between a 30 watt transmitter and the antenna, with 5 watts reflected. How much power is actually radiated?
  90. #390 A vertical 1/4 wave antenna receives signals:
  91. #391 The resonant frequency of a Hertz antenna can be lowered by:
  92. #392 An excited 1/2 wavelength antenna produces:
  93. #393 To increase the resonant frequency of a 1/4 wavelength antenna:
  94. #394 What happens to the bandwidth of an antenna as it is shortened through the use of loading coils?
  95. #395 To lengthen an antenna electrically, add a:
  96. #396 What is the meaning of the term velocity factor of a transmission line?
  97. #397 What determines the velocity factor in a transmission line?
  98. #398 Nitrogen is placed in transmission lines to:
  99. #399 A perfect (no loss) coaxial cable has 7 dB of reflected power when the input is 5 watts. What is the output of the transmission line?
  100. #400 Referred to the fundamental frequency, a shorted stub line attached to the transmission line to absorb even harmonics could have a wavelength of:

Element 3 questions: what to expect

Q How many Element 3 questions are in the GMDSS pool?

There are 605 Element 3 questions on this site, every one released by the U.S. Coast Guard or taken from the National Maritime Center's sample examinations, with its correct answer. The exam draws its Element 3 module from the same pool.

Q What score do I need to pass the Element 3 module?

Most USCG exam modules, including Element 3, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Element 3 exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

About the GMDSS question pool

These are the published GMDSS Element 3 questions covering general radiotelephone operator knowledge: radio law, operating procedures, and equipment fundamentals.