USCG Marine Communications and GMDSS 2 — Questions and Answers
Question 1: Which GMDSS Sea Area is defined as within VHF shore-based DSC coverage, typically within 20-30 miles of shore?
- Sea Area A1 (Correct answer)
- Sea Area A2
- Sea Area A3
- Sea Area A4
Correct answer: Sea Area A1
Sea Area A1 is defined as the area within range of VHF shore-based DSC stations, generally within 20-30 nautical miles of the coast.
Question 2: What is the function of a SART (Search and Rescue Transponder)?
- Sending distress calls via satellite
- Locating survival craft by responding to X-band radar pulses (Correct answer)
- Communicating voice messages to rescuers
- Automatically activating the vessel's AIS system
Correct answer: Locating survival craft by responding to X-band radar pulses
A SART responds to X-band (9 GHz) radar pulses from searching vessels or aircraft, displaying a series of dots on the radar screen to pinpoint the location of survivors.
Question 3: What is the primary purpose of two-way VHF portable radios required in survival craft under GMDSS?
- Contacting commercial shipping for navigation updates
- On-scene communications between survivors and rescue units (Correct answer)
- Transmitting vessel position to satellites
- Broadcasting weather information to the crew
Correct answer: On-scene communications between survivors and rescue units
Two-way VHF portable radios in survival craft are used for on-scene communications between survivors and SAR rescue units during rescue operations.
Question 4: What does the COSPAS-SARSAT system primarily do?
- Provides GPS navigation for commercial vessels
- Detects and locates 406 MHz emergency beacons including EPIRBs and PLBs (Correct answer)
- Monitors vessel traffic in coastal waters
- Controls VHF radio frequency assignments in ports
Correct answer: Detects and locates 406 MHz emergency beacons including EPIRBs and PLBs
COSPAS-SARSAT is an international satellite-based search and rescue system that detects and locates distress signals from 406 MHz emergency beacons.
Question 5: Which frequency band does NAVTEX use for international maritime safety broadcasts?
- VHF (156-174 MHz)
- MF (518 kHz and 490 kHz) (Correct answer)
- HF (4-27.5 MHz)
- UHF (300-3000 MHz)
Correct answer: MF (518 kHz and 490 kHz)
NAVTEX operates on medium frequency, primarily 518 kHz for international broadcasts in English and 490 kHz for national language broadcasts.
Question 6: What vessel identifier is automatically transmitted when a DSC distress alert is sent?
- The vessel's call sign
- The vessel's MMSI number (Correct answer)
- The vessel's IMO number
- The master's license number
Correct answer: The vessel's MMSI number
A DSC distress alert automatically transmits the vessel's unique 9-digit MMSI number along with the nature of distress and GPS position when connected.
Question 7: What is the watch-keeping requirement for VHF Channel 16 on GMDSS-equipped vessels while at sea?
- Only when in port
- Only during daylight hours
- Continuous watch while at sea (Correct answer)
- At scheduled 4-hour intervals
Correct answer: Continuous watch while at sea
GMDSS vessels must maintain continuous watch on VHF Channel 16 while at sea because it is the international distress and calling frequency.
USCG Marine Communications and GMDSS 2
Which GMDSS Sea Area is defined as within VHF shore-based DSC coverage, typically within 20-30 miles of shore?