Marine radio operating in the 156–174 MHz band used for short-range ship-to-ship and ship-to-shore communications.
Quick facts
Regulation
SOLAS Chapter IV
Frequency
174 MHz
In practice
VHF radiotelephones are operated by certificated GMDSS operators holding at least a Short Range Certificate. In practice, deck officers use VHF for pilotage communications, vessel traffic service reporting, port operations, and ship-to-ship passing agreements. Officers must use the phonetic alphabet, standard IMO phrases, and correct radiotelephone procedure to ensure unambiguous communication in traffic separation scheme areas and in poor visibility. Annual testing of the DSC controller, transmitter output power, and antenna system connection is required under SOLAS IV/15 and the performance standards in ITU-R M.493.
Regulatory detail & full definition
VHF marine radio operates in the 156–174 MHz frequency band using frequency modulation, providing clear line-of-sight communications typically over a range of 20–50 nautical miles between vessels and coast stations, depending on antenna height. The International Telecommunication Union Radio Regulations allocate specific channels for different maritime purposes: Channel 16 (156.8 MHz) is the international distress, safety, and calling channel on which all SOLAS vessels must maintain a continuous watch, while Channel 70 is dedicated exclusively to digital selective calling for GMDSS alerting. SOLAS Chapter IV and the ITU Radio Regulations prescribe mandatory VHF equipment carriage and watchkeeping requirements.
VHF radiotelephones are operated by certificated GMDSS operators holding at least a Short Range Certificate. In practice, deck officers use VHF for pilotage communications, vessel traffic service reporting, port operations, and ship-to-ship passing agreements. Officers must use the phonetic alphabet, standard IMO phrases, and correct radiotelephone procedure to ensure unambiguous communication in traffic separation scheme areas and in poor visibility. Annual testing of the DSC controller, transmitter output power, and antenna system connection is required under SOLAS IV/15 and the performance standards in ITU-R M.493.