FELCOM501

Common issues

• Antenna dome cable connectors corrode at the mast head, causing intermittent loss of signal
• Terminal drops network registration after a power interruption and requires manual re-logon
• Condensation collects inside the antenna dome in humid climates, degrading receive performance
• Firmware or subscription/airtime provisioning is not kept current, causing call or data failures that only show up during a real distress test
• Distribution unit or junction box cabling develops chafe damage where it runs through deck glands
• Battery backup, where fitted, is not load-tested and fails silently until an actual power loss

Inspection checklist

• Review the GMDSS radio log and confirm required periodic checks have been recorded
• Check antenna dome for cracks, discoloration or physical damage from weather or ice
• Inspect above-deck cabling and connectors for corrosion, chafe or water ingress
• Verify battery backup capacity with a load test, not just a voltage check
• Confirm MMSI, ship's name and other programmed identifiers match the vessel's current documentation
• Perform a test call/registration check per the radio survey procedure
• Check alarm panel and repeater functions from the bridge
• Verify power supply changeover from main to emergency source is automatic and alarmed

Service intervals

Critical spares

• Spare antenna unit as fitted to this terminal
• Distribution unit fuses
• Interconnecting cable/connector set
• Backup battery unit, if fitted
• Handset/user terminal

Safety

• Maintain the manufacturer's recommended safe distance from the antenna during transmission to avoid RF exposure
• Do not key a test transmission while anyone is working directly in front of the antenna
• Isolate main and back-up power sources correctly before opening the below-deck distribution unit

Class survey

GMDSS equipment is surveyed annually under the Radio Survey (SOLAS Ch IV); the surveyor checks the radio log for required periodic tests, confirms battery capacity by test rather than voltage reading alone, and verifies that all GMDSS equipment listed on the ship's Safety Radio Certificate is fitted and functional.