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The Toolbox — Standards
Marine
FCC Part 80 marine radio specifications and GMDSS sea area definitions.
Marine Radio — FCC Part 80
| Specification | Value / Notes |
|---|---|
| VHF ship station max power | 25 watts |
| VHF low power (bridge-to-bridge) | 1 watt |
| Channel 16 watch requirement | Continuous while underway — all compulsory vessels |
| DSC controller channel | Channel 70 (156.525 MHz) — voice prohibited |
| Watch channel | Channel 16 (156.800 MHz) |
| 2182 kHz silent period | 3 minutes at :00 and :30 past each hour |
| MF transmitter minimum power (compulsory) | 60 watts PEP |
| EPIRB frequency | 406 MHz satellite + 121.5 MHz homing |
| SART operating frequency | 9 GHz (X-band radar) |
| Preliminary call maximum duration | 30 seconds on 2182 kHz or Ch 16 |
| Interval between unanswered calls | Minimum 2 minutes before repeating |
| GMDSS compulsory vessel threshold | SOLAS — 300 GT or more on international voyages |
| Survival craft transceiver min power | 1 watt output, 0.25W ERP minimum |
| Survival craft transceiver channel | Channel 16 — required |
| NAVTEX international frequency | 518 kHz |
| NAVTEX national frequency | 490 kHz |
GMDSS Sea Areas
| Specification | Value / Notes |
|---|---|
| Sea Area A1 | Within range of at least one VHF coast station with DSC — typically 20–50 nm |
| Sea Area A2 | Within range of at least one MF coast station with DSC — typically 150–400 nm, excluding A1 |
| Sea Area A3 | Within INMARSAT geostationary satellite coverage — approximately 70°N to 70°S, excluding A1 and A2 |
| Sea Area A4 | All other sea areas — primarily polar regions above/below 70° latitude |
| A1 required equipment | VHF radio with DSC, NAVTEX receiver, SART, EPIRB, float-free transponder |
| A2 required equipment | A1 equipment plus MF radio with DSC |
| A3 required equipment | A2 equipment plus INMARSAT or MF/HF with DSC |
| A4 required equipment | A3 equipment plus HF radio with DSC |