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GMDSS Maintainer
Element 9
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GMDSS Maintainer · 299 questions

Element 9 - USCG Exam Questions

GMDSS maintenance practices and procedures: VHF, MF-HF and satellite equipment, power supplies, digital theory, troubleshooting and the regulations for sea areas A3 and A4. The exam asks 50 questions; 38 correct passes.

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.

Random question Start at question 1 Build a timed exam

All Element 9 questions

Questions 1–100 of 299 · page 1 of 3

  1. #1 What are the correct VHF Channels and Frequencies for Calling/Distress, DSC and bridge-to-bridge operations?
  2. #2 What is the frequency separation between Transmit and Receive frequencies on a duplex channel?
  3. #3 What is the assigned channel spacing for VHF channels?
  4. #4 What is the allowed frequency tolerance for the DSC carrier frequencies?
  5. #5 Using a frequency counter with an accuracy of 2 ppm — which of the following are within legal tolerance for the frequencies of 156.800 MHz and 156.525...
  6. #6 Using a frequency counter with an accuracy of 5 ppm — which of the following are within legal tolerance for the frequencies of 156.875 MHz and 157.200...
  7. #7 What is the purpose of the USA-INT switch?
  8. #8 What may happen if the USA-INT control is left on INT when in U.S. waters?
  9. #9 What is the purpose of the Dual Watch function?
  10. #10 What is the proper adjustment of the squelch control for maximum sensitivity?
  11. #11 Which of the following transmitter power levels are permitted by FCC rules?
  12. #12 Which of the following controls is not found on a VHF-DSC transceiver?
  13. #13 Which of the following best describes the “Capture effect?”
  14. #14 Which of the following may be adjusted in a FM ratio detector for improved signal-to-noise?
  15. #15 What is the function of a properly adjusted limiter circuit?
  16. #16 Which of the following are true about SINAD measurements?
  17. #17 What would be considered a normal sensitivity for 10 db of quieting in a VHF marine receiver?
  18. #18 What is meant by “full quieting” in a FM VHF receiver?
  19. #19 What condition may prevent a VHF radio receiver from staying tuned to the desired channel?
  20. #20 What fault may exist if a VHF radio receiver fails to produce audible output from the speaker and the squelch control has no effect?
  21. #21 What is indicated if a VHF radio fails to receive nearby stations and a voltmeter connected between the positive side of a radio’s DC line and ground...
  22. #22 What condition may prevent a VHF radio receiver from receiving a weak signal?
  23. #23 Which of the following is the best test procedure to isolate the source of distortion in the audio output of a receiver?
  24. #24 What condition may cause a significant loss in VHF receiver sensitivity?
  25. #25 Which of the following test procedures may be used to determine a VHF receiver’s minimum discernible signal?
  26. #26 Which of the following procedures may be used in many U.S. ports as a quick field test to determine if a shipboard VHF receiver is operating properly?
  27. #27 What ohmmeter reading may indicate a faulty component in a VHF receiver?
  28. #28 What condition may indicate a VHF receiver fault?
  29. #29 What condition may cause noisy operation of a VHF receiver?
  30. #30 What is the maximum allowable deviation of a marine VHF transmitter?
  31. #31 What is the modulation index?
  32. #32 How is pre-emphasis used in an FM transceiver?
  33. #33 A modulation index set to less than 1 to 1 may result in what?
  34. #34 What is the most common type of emission for shipboard VHF-DSC transceivers?
  35. #35 How many sidebands does a VHF FM transmitter have?
  36. #36 What condition may be indicated if a VHF radio is unable to contact nearby stations and an inline wattmeter indicates power outputs of 1 watt (LOW pow...
  37. #37 Antenna system matching can be analyzed by determining the Standing Wave Ratio (SWR). Which of the following is the best test procedure to measure the...
  38. #38 A mismatched antenna system can degrade marine VHF radio performance. Antenna system matching can be analyzed by determining the Standing Wave Ratio (...
  39. #39 What may be indicated if a VHF radio operates normally but the transmitter produces nearly zero RF output in the high power mode on all marine channel...
  40. #40 What condition may indicate voltage controlled oscillator failure in the synthesizer of a VHF transmitter?
  41. #41 What condition may exist if a VHF radio is operational in receive mode but unable to transmit?
  42. #42 What condition may be indicated if a VHF radio cannot contact nearby stations on any channel, an inline wattmeter indicates 25 watts output (HIGH powe...
  43. #43 What condition may be indicated if a VHF radio cannot contact nearby stations, an inline wattmeter indicates less than 1 watt output (HIGH power mode)...
  44. #44 A spectrum analyzer (SPECAN) can be a useful test instrument to troubleshoot a marine VHF radio. Which of the following is the best procedure to evalu...
  45. #45 Which in-line RF power reading indicates the proper operation of a VHF marine transmitter?
  46. #46 What condition may cause distortion in the modulator stage of a marine VHF transmitter?
  47. #47 What terms are used to describe a device used to test the RF power output of a marine VHF transmitter without emitting a signal on the air?
  48. #48 What is the correct frequency shift and sub-carrier for VHF-DSC?
  49. #49 What is the correct modulation rate and index of modulation for VHF-DSC?
  50. #50 How might a DSC radio check be accomplished with a coast station?
  51. #51 You attempt to program a new MMSI into a VHF radio with an existing MMSI. The radio will not accept the entry. What is the best course of action to co...
  52. #52 What is the time diversity reception interval for a VHF-DSC call?
  53. #53 What might a voltmeter indicate when testing a DSC circuit for an outgoing message data stream?
  54. #54 It becomes necessary to construct a temporary VHF marine antenna. What should be the approximate length of the antenna?
  55. #55 Which of the following best describes a VHF collinear array?
  56. #56 A masthead antenna with a base loading coil appears shorted to an ohmmeter check. What might this indicate?
  57. #57 What is the most common type of coax connector used on VHF transceivers?
  58. #58 What type of coaxial cable would be most appropriate for a long transmission line run?
  59. #59 What is a disadvantage when using high gain VHF antennas?
  60. #60 What is the assigned bandwidth and channel spacing for J3E voice transmissions?
  61. #61 What is the assigned bandwidth and channel spacing for J2B SITOR (NBDP) transmissions?
  62. #62 What is the allowable frequency tolerance for GMDSS MF-HF transmitters?
  63. #63 Using a frequency counter with an accuracy of 2 ppm which of the following are within legal tolerance for the frequencies of 2182.0 kHz and 4125.0 kHz...
  64. #64 Which of the following are assigned frequencies for Digital Selective Calling?
  65. #65 What are the assigned frequencies for VOICE and SITOR (NBDP) follow on communications?
  66. #66 What is the purpose of the “R.I.T.“ control on a MF/HF transceiver?
  67. #67 What is the function of the “TUNE” button on a MF/HF transceiver?
  68. #68 What is the purpose of the “ENTER” function.
  69. #69 What mode is a MF/HF transceiver operating in when “TLX” displayed?
  70. #70 Reducing the “RF Gain” control on an MF/HF transceiver has what effect?
  71. #71 What is the function of an “AGC” button?
  72. #72 What is the purpose of the BFO?
  73. #73 If the BFO is turned off what kind of emissions can still be received?
  74. #74 If you are listening to another vessel’s HF transmission and it sounds garbled what should you do?
  75. #75 What characteristics are desirable in an AGC circuit for SSB voice reception?
  76. #76 What is the primary purpose of both a high and a low I.F. system in a HF receiver?
  77. #77 How does a noise blanker circuit work in a HF receiver?
  78. #78 The voice is garbled and unreadable on MF/HF SSB channels. What is the most likely cause?
  79. #79 All signals sound normal on an MF/HF receiver except one that has a very high pitched voice barely readable. What is the most likely cause?
  80. #80 You are able to hear signals in the voice/SSB mode but not in the SITOR (NBDP) mode. What is the most likely cause?
  81. #81 The phase locked loop circuit in an MF/HF receiver appears to be faulty. What is the most likely cause?
  82. #82 You are able to hear signals in the SITOR (NBDP) mode but not in the voice/SSB mode. What is the most likely cause?
  83. #83 The AGC function of an MF/HF receiver is inoperative. What is the most likely cause?
  84. #84 The MF/HF receiver fails to suppress the AF output in the absence of a sufficiently strong input signal. What is the most likely cause?
  85. #85 The MF/HF receiver fails to produce any AF output. An ohmmeter reading is near zero between speaker leads. What is the most likely cause?
  86. #86 The MF/HF transceiver produces strong AF output but no signals are heard on any frequency. What is the most likely cause?
  87. #87 The MF/HF transceiver produces strong AF output but no signals are heard on any frequency. What is the most likely cause?
  88. #88 The MF/HF transceiver fails to produce AF output but the radio is powered on and “TX” is illuminated. What is the most likely cause?
  89. #89 A received signal on a MF/HF transceiver breaks up rapidly and repeatedly. The signal alternates between mid scale and zero on the “Signal” meter. Wha...
  90. #90 How is a J3E signal generated?
  91. #91 What would be the most likely power level to use for initial MF-HF communications?
  92. #92 How is the lower sideband eliminated?
  93. #93 What is the most common method of generating a SITOR (NBDP) signal on shipboard GMDSS equipment?
  94. #94 What are the major components of a phase locked loop frequency synthesizer?
  95. #95 What is the purpose of a phase comparator in a frequency synthesizer?
  96. #96 An MF-HF transceiver works properly on voice but not SITOR (NBDP). What is the most likely source of the problem?
  97. #97 Which of the following conditions would indicate the malfunction of a 2182 kHz radiotelephone system?
  98. #98 Which would be an indication of proper operation of a SSB transmitter rated at 60 watt PEP output?
  99. #99 An MF-HF transceiver is functioning correctly in voice mode/SSB but not in SITOR (NBDP). What is the most likely source of the problem?
  100. #100 Which of the following conditions would be a symptom of malfunction in a 2182 kHz SSB radiotelephone?

Element 9 questions: what to expect

Q How many Element 9 questions are in the GMDSS Maintainer pool?

There are 299 Element 9 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 9 module from the same pool.

Q What score do I need to pass the Element 9 module?

Most USCG exam modules, including Element 9, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Element 9 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 Maintainer question pool

The FCC Element 9 pool for the GMDSS Radio Maintainer licence: radio system theory, amplifiers, power sources, troubleshooting, digital theory and GMDSS equipment regulations for sea areas A3 and A4.