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GMDSS GOC Flashcards: Radio Concepts and Terminology

80 original English cards for maritime radio trainees: GMDSS terms, current sea-area concepts, selected channels, identification, MSI and alerting distinctions.

By author Open Study Contributor

About this deck

Practise 80 original English concept cards for GMDSS GOC revision. The scope is a selected theory subset referenced to the active CEPT ERC/DEC/(99)01 Annex 1 syllabus, amended 8 March 2024. It is not a complete GOC course or a national examination guide. Reviewed for 2026; sea-area concepts reflect the SOLAS changes effective 1 January 2024.

Recall a term’s meaning or function, identify selected channel/frequency uses, interpret basic MMSI patterns and NAVTEX header fields, and distinguish concepts in six short reasoning prompts. Selected applications revisit DSC channel use, HF propagation, ship-specific A3 coverage, NAVTEX coverage versus service area, voyage planning and the limits of beacon return-link confirmation. Basics come before dependent cases; related variants are separated by at least three unrelated cards. The app schedules later repetition. Public tags are gmdss plus basics, radio, safety-info or alerting.

Excluded: complete emergency scripts and action sequences; distress acknowledgement, relay and cancellation procedures; live testing; equipment operation or repair; full communication drills; national eligibility, renewal and carriage rules; billing and complete examination coverage. Those tasks need current approved training, vessel procedures, publications and the actual equipment manual. Flashcard recall does not establish practical competence, certification or readiness to manage an emergency.

All questions and answers were independently written with AI assistance and checked against public authoritative factual sources. The cover is an original AI-generated illustration, not an equipment guide. No examination questions, mark schemes or curriculum text were copied. CC0 applies only to original expression, organisation, metadata and generated media to the extent applicable rights exist; it does not license source publications or claim ownership of facts.

Independent, unofficial study material by Open Study Contributor. No affiliation with or endorsement by CEPT/ECC, IMO, ITU, Inmarsat, Iridium or any certification authority is claimed. See the official CEPT syllabus and implementation information; national requirements must be checked with the relevant administration.

Cards in this deck

  1. Card 1

    Question

    In maritime radio, what does GMDSS stand for?

    Answer

    Global Maritime Distress and Safety System.

  2. Card 2

    Question

    In the CEPT maritime-radio syllabus, what does GOC stand for?

    Answer

    General Operator’s Certificate.

  3. Card 3

    Question

    What does a radio frequency of 1 Hz represent?

    Answer

    One cycle per second.

  4. Card 4

    Question

    In GMDSS, what does MSI stand for?

    Answer

    Maritime Safety Information.

  5. Card 5

    Question

    Which international organisation develops the maritime safety framework behind GMDSS?

    Answer

    The International Maritime Organization (IMO).

  6. Card 6

    Question

    Which international organisation maintains the Radio Regulations used by maritime radio services?

    Answer

    The International Telecommunication Union (ITU).

  7. Card 7

    Question

    GMDSS combines which two broad communication paths?

    Answer

    Terrestrial radio and satellite communication.

  8. Card 8

    Question

    In maritime radio, what does DSC stand for?

    Answer

    Digital Selective Calling.

  9. Card 9

    Question

    Which maritime emergency category means grave and imminent danger requiring immediate assistance?

    Answer

    Distress.

  10. Card 10

    Question

    What is the purpose of NAVTEX?

    Answer

    Automatic reception of broadcast maritime safety information as text.

  11. Card 11

    Question

    In maritime radio, what does MMSI stand for?

    Answer

    Maritime Mobile Service Identity.

  12. Card 12

    Question

    In maritime satellite communications, what does SES stand for?

    Answer

    Ship Earth Station: the satellite-communication station aboard a ship.

  13. Card 13

    Question

    In maritime safety, what does EPIRB stand for?

    Answer

    Emergency Position-Indicating Radio Beacon.

  14. Card 14

    Question

    How many hertz are in 1 kHz?

    Answer

    1000 Hz.

  15. Card 15

    Question

    In maritime communications, what does SAR stand for?

    Answer

    Search and Rescue.

  16. Card 16

    Question

    What is the basic role of maritime DSC?

    Answer

    Establishing contact and transferring calling or alert information using digital codes.

  17. Card 17

    Question

    In radio spectrum terminology, what does MF mean?

    Answer

    Medium frequency: 300 kHz to 3 MHz.

  18. Card 18

    Question

    What is the international NAVTEX frequency?

    Answer

    518 kHz.

  19. Card 19

    Question

    How many digits does an MMSI contain?

    Answer

    Nine digits.

  20. Card 20

    Question

    Which category concerns an urgent safety message without the distress condition requiring immediate assistance?

    Answer

    Urgency.

  21. Card 21

    Question

    In radio spectrum terminology, what does HF mean?

    Answer

    High frequency: 3 to 30 MHz.

  22. Card 22

    Question

    In GMDSS, what does RMSS mean?

    Answer

    Recognised Mobile Satellite Service: a satellite service recognised by IMO for GMDSS.

  23. Card 23

    Question

    How many kilohertz are in 1 MHz?

    Answer

    1000 kHz.

  24. Card 24

    Question

    In a NAVTEX header, what does B1 identify?

    Answer

    The transmitter.

  25. Card 25

    Question

    In radio spectrum terminology, what does VHF mean?

    Answer

    Very high frequency: 30 to 300 MHz.

  26. Card 26

    Question

    Which category announces navigation-safety information or important meteorological warnings?

    Answer

    Safety.

  27. Card 27

    Question

    Which radio coverage defines GMDSS sea area A1?

    Answer

    VHF coast-station voice coverage with continuous DSC alerting, as defined by a Contracting Government.

  28. Card 28

    Question

    What do the Maritime Identification Digits in an MMSI identify?

    Answer

    The administration with jurisdiction over the station.

  29. Card 29

    Question

    In a NAVTEX header, what does B2 identify?

    Answer

    The message subject category.

  30. Card 30

    Question

    Which spoken maritime radio signal denotes distress?

    Answer

    MAYDAY.

  31. Card 31

    Question

    Which radio coverage defines GMDSS sea area A2?

    Answer

    MF coast-station voice coverage with continuous DSC alerting, outside A1, as defined by a Contracting Government.

  32. Card 32

    Question

    What atmospheric region enables HF skywave communication beyond the horizon?

    Answer

    The ionosphere.

  33. Card 33

    Question

    What do the B3B4 characters in a NAVTEX header represent?

    Answer

    The two-digit message number.

  34. Card 34

    Question

    Which spoken maritime radio signal denotes urgency?

    Answer

    PAN PAN.

  35. Card 35

    Question

    Since 1 January 2024, what determines a ship’s GMDSS sea area A3?

    Answer

    Its carried ship earth station’s recognised mobile satellite service coverage with continuous alerting, outside A1 and A2.

  36. Card 36

    Question

    Which language is used by the international NAVTEX service on 518 kHz?

    Answer

    English.

  37. Card 37

    Question

    In ITU radio terminology, how do the two directions operate in simplex communication?

    Answer

    Alternately: one direction transmits at a time.

  38. Card 38

    Question

    Which spoken maritime radio signal introduces safety traffic?

    Answer

    SÉCURITÉ (SECURITE).

  39. Card 39

    Question

    How is GMDSS sea area A4 defined?

    Answer

    The area outside A1, A2 and that ship’s A3.

  40. Card 40

    Question

    Which NAVTEX subject category does B2 = A represent?

    Answer

    Navigational warnings.

  41. Card 41

    Question

    In ITU radio terminology, what does duplex operation permit?

    Answer

    Simultaneous transmission in both directions.

  42. Card 42

    Question

    What is the priority order of distress, urgency, safety and routine radio traffic?

    Answer

    Distress → urgency → safety → routine.

  43. Card 43

    Question

    Which marine VHF channel is reserved for DSC?

    Answer

    Channel 70, 156.525 MHz; it is not a voice channel.

  44. Card 44

    Question

    Which NAVTEX subject category does B2 = B represent?

    Answer

    Meteorological warnings.

  45. Card 45

    Question

    Which frequency band identifies the satellite distress-alerting function of a modern EPIRB?

    Answer

    406 MHz.

  46. Card 46

    Question

    What are bridge-to-bridge communications in GMDSS terminology?

    Answer

    Safety radio communications between ships from their navigating positions.

  47. Card 47

    Question

    Which marine VHF channel carries radiotelephony distress and safety traffic?

    Answer

    Channel 16, 156.8 MHz.

  48. Card 48

    Question

    Which NAVTEX subject category does B2 = E represent?

    Answer

    Meteorological forecasts.

  49. Card 49

    Question

    What does integrated GNSS add to an EPIRB distress alert?

    Answer

    An encoded position from a Global Navigation Satellite System, helping rescuers locate the beacon.

  50. Card 50

    Question

    Which GMDSS communication function concerns units at the incident location?

    Answer

    On-scene communications.

  51. Card 51

    Question

    Which MF frequency is used for DSC distress and safety calling?

    Answer

    2187.5 kHz.

  52. Card 52

    Question

    Which NAVTEX subject category does B2 = C represent?

    Answer

    Ice reports.

  53. Card 53

    Question

    Why does accurate EPIRB registration help rescue authorities?

    Answer

    It links the beacon identity to vessel and contact information.

  54. Card 54

    Question

    What is the purpose of a GMDSS reserve source of energy?

    Answer

    Powering distress and safety radio equipment if main and emergency electrical supplies fail.

  55. Card 55

    Question

    Which MF frequency is used for radiotelephony distress and safety communications?

    Answer

    2182 kHz.

  56. Card 56

    Question

    Name the lower-frequency national NAVTEX channel distinct from international 518 kHz.

    Answer

    490 kHz; availability and language depend on the national service.

  57. Card 57

    Question

    What is the role of an EPIRB’s low-power 121.5 MHz signal?

    Answer

    Local homing by rescue units; Cospas-Sarsat satellites no longer process 121.5 MHz alerts.

  58. Card 58

    Question

    Does the CEPT GOC syllabus assess theory alone?

    Answer

    No. It requires theoretical and practical tests.

  59. Card 59

    Question

    At the same wave speed, what happens to wavelength when frequency rises?

    Answer

    Wavelength becomes shorter.

  60. Card 60

    Question

    In maritime satellite safety broadcasts, what does EGC stand for?

    Answer

    Enhanced Group Call.

  61. Card 61

    Question

    What is the purpose of a float-free EPIRB’s hydrostatic release?

    Answer

    Releasing the beacon from its bracket when submerged, so it can float free.

  62. Card 62

    Question

    Why does GMDSS communication planning consider the whole voyage?

    Answer

    Service coverage, relevant stations and safety-information areas can change along the route.

  63. Card 63

    Question

    What is the standard ship-station MMSI pattern, using MID and X placeholders?

    Answer

    MIDXXXXXX: three Maritime Identification Digits followed by six digits.

  64. Card 64

    Question

    Which named Inmarsat service broadcasts maritime safety information?

    Answer

    SafetyNET.

  65. Card 65

    Question

    Does a beacon Return Link Service (RLS) indication mean a rescue has been launched?

    Answer

    No. It confirms receipt, localisation and forwarding of the alert, not launch of a rescue.

  66. Card 66

    Question

    Two ships share a position outside A1/A2 but carry different RMSS terminals. Must their A3 coverage match?

    Answer

    No. A3 depends on the RMSS supported by each ship’s carried earth station.

  67. Card 67

    Question

    What is the coast-station MMSI pattern, using MID and X placeholders?

    Answer

    00MIDXXXX: two leading zeros, the MID, then four digits.

  68. Card 68

    Question

    Which named Iridium service broadcasts maritime safety information?

    Answer

    SafetyCast.

  69. Card 69

    Question

    Why use an EPIRB’s approved self-test instead of ordinary activation for practice?

    Answer

    Ordinary activation can transmit a real distress alert and divert rescue resources.

  70. Card 70

    Question

    What is a NAVAREA used to coordinate?

    Answer

    Navigational warnings for a defined sea area.

  71. Card 71

    Question

    What is the primary role of a radar SART?

    Answer

    Helping nearby rescue units locate survivors through a radar response. SART means Search and Rescue Transponder.

  72. Card 72

    Question

    A training question asks for voice transmission on VHF channel 70. What is the conceptual error?

    Answer

    Channel 70 is for DSC, not radiotelephony.

  73. Card 73

    Question

    What is a METAREA used to coordinate?

    Answer

    Marine meteorological warnings and forecasts for a defined sea area.

  74. Card 74

    Question

    Which IAMSAR volume is intended for vessels and other mobile facilities?

    Answer

    Volume III, Mobile Facilities.

  75. Card 75

    Question

    Why can an HF link become unreliable during disturbed space weather?

    Answer

    Changes in the ionosphere can degrade or disrupt HF propagation.

  76. Card 76

    Question

    Which radar band does a GMDSS radar SART use?

    Answer

    9.2–9.5 GHz, in the 9 GHz/X-band radar region.

  77. Card 77

    Question

    Why is preventing false distress alerts a safety issue?

    Answer

    False alerts can divert search-and-rescue resources from real emergencies.

  78. Card 78

    Question

    Does receiving a NAVTEX transmitter’s signal prove that every received warning concerns the ship’s position?

    Answer

    No. Radio coverage and the transmitter’s defined service area are different concepts.

  79. Card 79

    Question

    A training display says an RLS alert was received. What rescue outcome must not be inferred?

    Answer

    That rescue units have already been dispatched or will arrive at a particular time.

  80. Card 80

    Question

    How does an AIS-SART provide a locating signal?

    Answer

    By transmitting search-and-rescue locating information on Automatic Identification System (AIS) frequencies.

Original illustration of a maritime radio and handset on a ship’s bridge, with a vessel at sea beyond the window.

80 cards

GMDSS GOC Flashcards: Radio Concepts and Terminology

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