FCC GMDSS Maintainer study guide
FCC GMDSS Maintainer · Work through your exam, one topic at a time.
The FCC GMDSS Radio Maintainer's License is a United States commercial radio operator credential for technicians who maintain Global Maritime Distress and Safety System equipment aboard ships. It is aimed at field service engineers, shipboard electronics officers, and shore-based maintenance providers who keep DSC controllers, Inmarsat terminals, NAVTEX receivers, EPIRBs, SARTs, and associated power and antenna systems operational. The FCC GMDSS Maintainer study guide has 9 sections and about 3,446 words.
01GMDSS system overview and regulatory framework
GMDSS is the SOLAS Chapter IV radio system for distress alerting, SAR coordination, locating, maritime safety information (MSI), and general communications. It applies to passenger ships and cargo ships of 300 gross tonnage and above on international voyages.
437 words, about 2 min02Distress, urgency and safety communications procedures
GMDSS uses three priority signals. MAYDAY is distress, for grave and imminent danger requiring immediate assistance.
379 words, about 2 min03Digital selective calling (DSC) equipment
A DSC message contains format, address, category, nature of distress or communication priority, position and time, telecommand, and end-of-sequence. Formats include individual, all ships, group, and geographic area.
368 words, about 2 min04Radiotelephony and narrow-band direct-printing (NBDP) equipment
GMDSS radiotelephony uses VHF FM and MF/HF single-sideband suppressed-carrier telephony. NBDP uses frequency-shift keying, commonly 100 baud with 170 Hz shift, and a seven-unit constant-ratio code.
372 words, about 2 min05Satellite communications (Inmarsat) systems
Inmarsat uses geostationary satellites covering four ocean regions: Atlantic Ocean East, Atlantic Ocean West, Pacific Ocean, and Indian Ocean. A terminal communicates through a land earth station (LES), coordinated by a network coordination station (NCS).
373 words, about 2 min06Emergency position-indicating radio beacons (EPIRB) and search and rescue radar transponders (SART)
A 406 MHz EPIRB transmits a digital distress alert to the Cospas-Sarsat system, with a low-power 121.5 MHz homing signal for aircraft and SAR units. GNSS-equipped beacons include position in the alert.
378 words, about 2 min07Maritime Safety Information (MSI) and NAVTEX/SafetyNET reception
MSI includes navigational warnings, meteorological warnings and forecasts, SAR information, piracy warnings, and other urgent safety information. It is broadcast through NAVTEX, Inmarsat EGC SafetyNET, and HF NBDP.
370 words, about 2 min08Power supplies, batteries and antennas
GMDSS installations need a reserve source of energy independent of the main and emergency switchboards, capable of supplying the required radio load for the period specified by SOLAS. That period is typically one hour where an emergency generator is provided and three hours otherwise; confirm the ship's particular requirement.
389 words, about 2 min09Installation, maintenance, testing and fault-finding practices
GMDSS maintenance may be by at-sea maintenance, shore-based maintenance, or equipment duplication, as allowed by the flag administration. The maintainer's role is to keep the installation compliant and available, not merely to repair after failure.
380 words, about 2 min