Nautical VHF radio
Nautical VHF radio is the backbone of maritime communications: it provides a reliable link between vessels, ports, and emergency services, from recreational boats to large commercial ships. Understanding its frequencies, coverage, and operating rules is essential for anyone working at sea.
Nautical VHF frequencies
The marine VHF band runs from 156.000 to 162.025 MHz, divided into internationally standardized channels: vessels of any nationality communicate on the same channels, anywhere in the world. Key channels:
| Channel | Frequency | Use |
|---|---|---|
| 16 | 156.800 MHz | Distress and international calling — continuously monitored by maritime authorities |
| 70 | 156.525 MHz | Digital Selective Calling (DSC) for automated distress alerts |
| 13 | 156.650 MHz | Bridge-to-bridge communications to prevent collisions |
| 72 | 156.625 MHz | Ship-to-ship, widely used by recreational boaters |
| 6 | 156.300 MHz | Safety between vessels |
| 68, 69, 71, 78 | — | Port operations and vessel movement per the ITU channel plan |
Nautical VHF coverage
VHF signals propagate line-of-sight: radio waves travel in a straight line and are affected by physical obstacles. The factors that determine range:
- Geography — mountains and cliffs reduce effective range; open water, free of obstructions, allows the widest coverage.
- Antenna height — the single most important factor: a higher antenna, on the vessel or at the coastal station, extends the radio horizon.
- Weather conditions — heavy rain and fog affect signal quality, though to a lesser extent than other frequency bands.
- Equipment quality — the onboard radio and antenna directly affect range and clarity.
On average, a fixed marine VHF radio with a properly elevated antenna covers 20–25 nautical miles in open water; smaller vessels with low-mounted antennas see range drop to 5–10 nautical miles.
What nautical VHF is used for
- Recreational boating — weather updates, contact with port services, and requests for assistance when needed.
- Commercial navigation — communications with ports, traffic coordination, and compliance with maritime regulations; channel 13 helps vessels maneuver safely in congested areas.
- Emergencies — channel 16 transmits distress signals to nearby vessels and the coast guard, and is monitored continuously worldwide.
- Port operations — port authorities manage berthing, loading, and unloading on dedicated channels, preventing incidents.
Nautical VHF and professional radiocommunications
The marine band is one of the few cases of global spectrum standardization: the same frequencies, the same channels, and the same procedures apply in every sea worldwide. For a deeper look at the differences between professional radio bands, read the VHF vs UHF comparison.
Teleproject designs and builds complete VHF radiocommunication systems — coastal base stations, repeaters, and networks for ports and maritime operators — with dedicated technical support.
Frequently asked questions
Is a license required to use a VHF radio on a boat?
Yes: in Italy, an onboard VHF set requires an operating license issued by the Ministry, and the operator must hold a Restricted Radiotelephone Operator Certificate. Handheld marine VHF radios are subject to the same rules.
Why must channel 16 always be monitored?
It is the international distress and calling frequency: all distress calls go through it, and every vessel underway contributes to collective safety by keeping a watch. Once contact is established, the conversation moves to a working channel.
What does DSC on channel 70 do?
Digital Selective Calling (DSC) automatically transmits a distress alert containing the vessel's identifier (MMSI) and, if connected to GPS, its position — even without a voice call. Channel 70 is reserved exclusively for this service.
Can I extend the range of my VHF radio?
The most effective method is raising the antenna: VHF range depends on the radio horizon, not just transmit power. Fixed marine radios transmit up to 25 W; handhelds typically 5 W — sufficient for local and emergency communications.