Under SOLAS Chapter IV and IMO Resolution A.1156(32) (Survey Guidelines under HSSC), every passenger ship and cargo vessel of 300 GT and above must successfully pass an Annual Radio Survey to maintain the validity of its Safety Radio Certificate. Verification covers primary GMDSS consoles, MF/HF telephony/DSC transceivers, VHF DSC installations, satellite emergency beacons, and dedicated emergency radio reserve power.
Engineering Overview & Table of Contents
- 1. Statutory Architecture & Annual Radio Survey Execution
- 2. MF/HF Transceiver, DSC Distress & Antenna Tuning Unit (ATU) Repair
- 3. Satellite GMDSS (Inmarsat-C, Fleet Safety) & NAVTEX Systems
- 4. Emergency Radio Battery Discharge Capacity Testing
- 5. Shore-Based Maintenance (SBM) Certification & Class Approvals
- 6. Emergency GMDSS Repairs Across Indian Ports
1. Statutory Architecture & Annual Radio Survey Execution
Seanav is class-approved by leading IACS members (including DNV, ABS, Lloyd’s Register, Bureau Veritas, ClassNK, and Indian Register of Shipping) to perform formal GMDSS Annual Radio Survey endorsements and initial GMDSS Commissioning. Our qualified radio surveyors carry certified, calibrated RF test equipment (Futronic GMDSS testers, spectrum analyzers, wattmeters, and battery discharge load banks) to conduct exhaustive physical and live on-air verification.
Our complete scope spans GMDSS Equipment Supply, GMDSS Installation, GMDSS Configuration, and full console diagnostics across Sailor / Cobham, Furuno, JRC, and Samyung consoles.
2. MF/HF Transceiver, DSC Distress & Antenna Tuning Unit (ATU) Repair
The medium and high frequency (MF/HF) radio suite guarantees long-range ship-to-shore and ship-to-ship distress alerting across Sea Areas A2, A3, and A4. Common failures arise from coastal humidity corroding high-voltage feedthrough insulators, whip antenna ground bonding degradation, or power amplifier MOSFET breakdown.
MF/HF Radio Engineering Workflows:
- MF/HF Radio Service & DSC Distress Calling: Testing distress transmissions on 2187.5 kHz and HF DSC frequencies (4207.5, 6312, 8414.5, 12577, 16804.5 kHz) using dedicated RF attenuators without broadcasting false alerts.
- Antenna Tuning Unit (ATU) Repair & ATU Inspection: Cleaning spark gaps, testing vacuum relays, verifying motorized roller inductor operation, and renewing copper ground earthing straps.
- VHF DSC Radio Service: Calibrating Channel 70 DSC receiver sensitivity, checking 25W/1W power output into dummy loads, and testing bridge wing remote handsets.
- Emergency VHF and MF/HF Radio Repair: Component-level motherboard repair, exciter module replacement, and RF PA transistor matching.
3. Satellite GMDSS (Inmarsat-C, Fleet Safety) & NAVTEX Systems
Reliable reception of Maritime Safety Information (MSI) and Enhanced Group Calling (EGC) is fundamental to navigational warnings, SAR broadcasts, and meteorological alerts. Seanav engineers inspect, test, and overhaul:
- Inmarsat-C GMDSS Inspection & Testing: Transmit/receive loopback testing, PV (Performance Verification) testing via Land Earth Stations (LES), diagnostic polling, and antenna dome moisture check.
- NAVTEX Receiver Repair & Configuration: 518 kHz international and 490 kHz / 4209.5 kHz national frequency reception testing, preamplifier whip antenna inspection, and thermal printer / serial display repair.
- EPIRB Shore-Based Maintenance (SBM): Hydrostatic release unit replacement, HRU expiry verification, 406 MHz COSPAS-SARSAT hex ID decoding, 121.5 MHz homing transmission test, and battery pack renewal.
- SART and AIS-SART Servicing: Radar transponder 9 GHz sweep ping verification, battery expiry audit, and physical watertight gasket replacement.
4. Emergency Radio Battery Discharge Capacity Testing
SOLAS Chapter IV Regulation 13 requires a reserve source of electrical energy capable of powering the GMDSS installation for either 1 hour (if an emergency generator is fitted) or 6 hours (if no emergency generator is installed). Our surveyors perform statutory GMDSS Battery Capacity Testing and Radio Battery Discharge Test procedures:
| Test Stage | Standard Criteria | Seanav Verification Service |
|---|---|---|
| Open Circuit Voltage & Specific Gravity | Float charge voltage > 25.6V DC (lead-acid / gel) | Electrolyte specific gravity logging and individual cell impedance evaluation. |
| Simulated Discharge Load Test | Terminal voltage > 21.6V DC under full transmit load | Constant current dummy load discharge; automatic cut-off and GMDSS Battery Replacement if degradation exceeds 20%. |
| Automatic Charger Re-charge Test | Recharge to 100% within 10 hours | Mains failure auto-transfer switch verification and battery charger float/boost calibration. |
5. Shore-Based Maintenance (SBM) Certification & Class Approvals
Vessels sailing in Sea Areas A2, A3, and A4 typically fulfill SOLAS Chapter IV, Reg. 15 maintenance requirements via a combination of equipment duplication and a valid GMDSS Shore-Based Maintenance (SBM) agreement. Seanav issues internationally recognized SBM certificates, backed by round-the-clock technical support, worldwide spare parts dispatch, and a comprehensive database of vessel equipment histories.
6. Emergency GMDSS Repairs Across Indian Ports
Should PSC officers or Class surveyors issue a deficiency regarding radio distress communications, our certified radio engineers mobilize on 2 hours’ notice with portable programming tools, spare VHF/MF transceivers, ATUs, antennas, and GMDSS batteries across Kandla, Mundra, Mumbai, JNPT, Cochin, Chennai, Visakhapatnam, and Kolkata.
Schedule Your Annual Radio Survey or Renew Shore-Based Maintenance
Read about our survey scope on our dedicated GMDSS Annual Radio Survey Hub or contact our technical operations team for immediate assistance at any Indian Commercial Port.
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- GMDSS & Radio Survey overview
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