Marine VHF radio

A standard handheld maritime VHF, mandatory on larger vessels under the GMDSS rules

A classical maritime VHF set

A portable VHF which is both ip67, GMDSS and ATEX approved.

A VHF set and a VHF channel 70 DSC set, the DSC on top, both produced by Sailor

Marine VHF radio is installed on all large ships and most seagoing small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas, and operates in the VHF frequency range, between 156 to 174 MHz. Although it is widely used for collision avoidance, its use for this purpose is contentious and is strongly discouraged by some countries, including the UK.^[1]

A marine VHF set is a combined transmitter and receiver and only operates on standard, international frequencies known as channels. Channel 16 (156.8 MHz) is the international calling and distress channel. Channel 9 can also be used in some places as a secondary call and distress channel. Transmission power ranges between 1 and 25 watts, giving a maximum range of up to about 60 nautical miles (111 km) between aerials mounted on tall ships and hills, and 5 nautical miles (9 km) between aerials mounted on small boats at sea-level.^[1] Frequency modulation is used, with vertical polarization, meaning that antennas have to be vertical in order to have good reception.

Modern day marine VHF radios not only offer basic transmit and receive capabilities, many package additional features that truly make these radios indispensable for the mariner. For the last several years all fixed mount marine VHF radios have required by certification some level of "Digital Selective Calling" (DSC) calling capability. Even the basic set has the ability to alert other boats, ships, and shore stations with a single button press. More expensive radios offer far more extensive DSC capabilities. These may include position polling or a variety of group calling options. Most mid-priced marine VHF radios integrate other features too. Many have the ability to connect to a remote microphone and act as an intership intercom system. Still others have a built-in hailer that when connected to an external hailer horn can act as a public address system and/or output required fog signals when conditions warrant. The most sophisticated marine VHF radios have an alphanumeric keypad for data entry, are able to connect to optional voice scramblers, and a few even have the ability to use a Bluetooth headset. The newest combination of features offered is the integration of a complete Class B AIS unit with a marine VHF radio.

Marine VHF mostly uses "half-duplex" transmission, where communication can only take place in one direction at a time. A transmit button on the set or microphone determines whether it is operating as a transmitter or a receiver. The majority of channels, however, are set aside for "duplex" transmissions channels where communication can take place in both directions simultaneously.^[1] Each duplex channel has two frequency assignments. This is mainly because, in the days before mobile phones and satcomms became widespread, the duplex channels could be used to place calls on the public telephone system for a fee via a marine operator. This facility is still available in some areas, though its use has largely died out. In US waters, Marine VHF radios can also receive weather radio broadcasts, where they are available, on special receive-only channels wx1, wx2, etc. or a normal channel reserved for broadcast in the area in question.

Types of equipment

Sets can be fixed or portable. A fixed set generally has the advantages of a more reliable power source, higher transmit power, a larger and more effective aerial and a bigger display and buttons. A portable set (often essentially a waterproof, VHF walkie-talkie in design) can be carried on a kayak, or to a lifeboat in an emergency, has its own power source and is water-proof if GMDSS approved. A few portable VHFs are even approved to be used as emergency radios in environments requiring intrinsically safe equipment (e.g. gas tankers, oil rigs, etc.).

Marine radios can be "voice-only" or can include "Digital Selective Calling" (DSC).

Voice-only equipment is the traditional type, which relies totally on the human voice for calling and communicating.

Digital Selective Calling equipment, a part of the Global Maritime Distress Safety System (GMDSS), provides all the functionality of voice-only equipment and, additionally, allows several other features:

• a transmitter can automatically call a receiver equipped with Digital Selective Calling, using a telephone-type number known as a Maritime Mobile Service Identity or MMSI. The DSC information is sent on the reserved Channel 70. When the receiver picks up the call, his active channel is automatically switched to the transmitter's channel and normal voice communication can proceed.
• a distress button, which automatically sends a digital distress signal identifying the calling vessel and the nature of the emergency
• a connection to a GPS receiver allowing the digital distress message to contain the distressed vessel's position

The MMSI is a nine digit number identifying a VHF set or group of sets. The left hand digits of MMSI indicate the country and type of station. For example, here are MMSI prefixes of four station types:

• Ship : 232, 233, 234 or 235 are the United Kingdom – e.g. a UK ship : 232003556
• Coast : 00 – e.g. Solent Coastguard : 002320011
• Group of stations : 0 – e.g. 023207823
• Portable DSC equipment : for UK 2359 - e.g. 235900498

Operating procedure

The accepted conventions for use of marine radio are collectively termed "proper operating procedure." These conventions include:

• Listening for 2 minutes before transmitting
• Using Channel 16 only to establish communication (if necessary) and then switch to a different channel
• using a set of international "calling" procedures such as the "Mayday" distress call, the "Pan-pan" urgency call and "Securité" navigational hazard call.
• using "pro-words" based on the English language such as Acknowledge, All after, All before, All stations, Confirm, Correct, Correction, In figures, In letters, Over, Out, Radio check, Read back, Received, Repeat, Say again, Spell, Standby, Station calling, This is, Wait, Word after, Word before, Wrong
• using the NATO phonetic alphabet: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu
• using a phonetic numbering system based on the English language: Wun, Too, Tree, Fow-er, Fife, Six, Sev-en, Ait, Nin-er, Zero, Decimal

Slightly adjusted regulations can apply for inland shipping, such as the Basle rules in Western Europe.

Marine VHF radio is sometimes illegally operated inland. Since enforcement is often the job of the local coast guard, enforcement away from the water is sometimes difficult.

Marine VHF Channels and Frequencies

Channel number	Frequencies (MHz)		United Kingdom [2]	United States	Canada	Australia	New Zealand	Finland[3]
	A  Usually ship stations	B  Usually coast stations
0	156.000	160.600	Private, coast guard  A
1	156.050	160.650			Public Correspondence (Ship-to-Shore Duplex) BC Coast			Public Correspondence (Ship-to-Shore Duplex) Port Operations
2	156.100	160.700			Public BC Coast			Public Correspondence (Ship-to-Shore Duplex) Port Operations
3	156.150	160.750		A  Illegal for public use1	Public BC Coast/Inland		Boat to Boat - Kawau	Public Correspondence (Ship-to-Shore Duplex) Port Operations
4	156.200	160.800			Ship-to-ship/shore, commercial and safety East Coast and Inland  A  Canadian Coast Guard - public working channel BC Coast4  A		Boat to Boat - Tutukaka/Raglan	Public Correspondence (Ship-to-Shore Duplex) Port Operations
5	156.250	160.850			Ship Movements			Public Correspondence (Ship-to-Shore Duplex) Port Operations
6	156.300	160.900	Ship-to-ship + Ship-to-Air  A		Ship-to-ship + Ship-to-Air  A	Distress - Ship-to-Air	Working - Intership	A  Ship-to-ship also SAR: Ship-to-Ship + Ship-to-Air
7	156.350	160.950			General working channel			Public Correspondence (Ship-to-Shore Duplex) Port Operations
8	156.400	161.000	Ship-to-ship  A		Ship-to-ship East and west coasts, Lake Winnipeg  A	Working - Intership	Working - Intership	A  Ship-to-ship
9	156.450	161.050	Frequently used by pilots  A	Calling  A , commercial and non-commercial.	Ship-to-air for maritime support Atlantic and BC coasts  A	Pilots, Port Operations	Port Operations	A  VTS (Ship-to-ship + Port Operations
10	156.500	161.100	Frequently used by HM Coastguard  A		Ship-to-air - SAR and antipollution  A  General working - Atlantic and BC coasts, Great Lakes		Port Operations	A  Ship-to-ship Port Operations also SAR and oil cleanup only VTS on Gulf of Finland
11	156.550	161.150	Port Operations		VTS - BC Coast Pilotage  A		Port Operations	A  Port Operations
12	156.600	161.200	Port Operations		VTS - BC Coast Port and pilot ops  A	Port Operations, VTS	Port Operations	A  Port Operations
13	156.650	161.250	Bridge-to-Bridge Working  A	Bridge-to-Bridge safety  A : Vessels > 20m must maintain watch, Tx limited to 1 watt. Movable bridge / lock operations.	VTS - BC Coast Bridge-to-bridge safety  A	Port Operations, VTS	Intership Nav Safety	A  Pilots Ship-to-ship Port Operations
14	156.700	161.300	Port Operations		VTS - BC Coast Port and pilot ops  A		Port Operations	A  Working channel for SAR authorities, Turku Radio (Port Operations)
15	156.750	161.350	On board working (limited to 1 watt)  A					A  max 1 W Intraship Ship-to-ship Port Operations
16	156.800	156.800	International distress, safety and calling  A  USA: All vessels equipped with VHF must maintain watch.
17	156.850	161.450	On board Working  A				Aquatic Sports Events	A  max 1 W Intraship Ship-to-ship Port Operations
18	156.900	161.500						Public Correspondence (Ship-to-Shore Duplex) Port Operations
19	156.950	161.550		Landside facilities: harbormaster, marinas.	Canadian Coast Guard - Working Channel			Public Correspondence (Ship-to-Shore Duplex) Port Operations
20	157.000	161.600				Repeater Operations	Continuous Weather Maritime Safety Service	Public Correspondence (Ship-to-Shore Duplex) Port Operations
21	157.050	161.650		A  U.S. Coast Guard Only	Continuous marine broadcasts  B  (WX 8)		Continuous Weather Maritime Safety Service	Public Correspondence (Ship-to-Shore Duplex) Port Operations
22	157.100	161.700		A  U.S. Coast Guard—public working channel2			Continuous Weather Maritime Safety Service	Public Correspondence (Ship-to-Shore Duplex) Port Operations
23	157.150	161.750	HM Coastguard Maritime Safety Information	A  U.S. Coast Guard Only			Continuous Weather Maritime Safety Service	Public Correspondence (Ship-to-Shore Duplex) Port Operations
24	157.200	161.800	UKSAR G/A Winching  A  UKSAR TWC  B					Public Correspondence (Ship-to-Shore Duplex) Port Operations
25	157.250	161.850					Maritime Radio Working Channel	Public Correspondence (Ship-to-Shore Duplex) Port Operations
26	157.300	161.900	HM Coastguard Maritime Safety Information	Public correspondence (marine telephone operator)				Public Correspondence (Ship-to-Shore Duplex) Port Operations
27	157.350	161.950						Public Correspondence (Ship-to-Shore Duplex) Port Operations
28	157.400	162.000						Public Correspondence (Ship-to-Shore Duplex) Port Operations
60	156.025	160.625						GOFREP on Gulf of Finland Public Correspondence (Ship-to-Shore Duplex) Port Operations
61	156.075	160.675		A  Illegal for public use1				GOFREP (Estonia) on Gulf of Finland Public Correspondence (Ship-to-Shore Duplex) Port Operations
62	156.125	160.725	UKSAR Calling & Helicopter Channel  A  UKSAR TWC  B				Boat to Boat - Waiheke/Whangaroa	Public Correspondence (Ship-to-Shore Duplex) Port Operations
63	156.175	160.775	UKSAR TWC (simplex)				Boat to Boat - Manukau	Public Correspondence (Ship-to-Shore Duplex) Port Operations
64	156.225	160.825	UKSAR TWC (simplex)	A  Illegal for public use1				Public Correspondence (Ship-to-Shore Duplex) Port Operations
65	156.275	160.875			Marine Assistance Working Channel		Boat to Boat - Coromandel	Public Correspondence (Ship-to-Shore Duplex) Port Operations
66	156.325	160.925			Marinas - BC Coast  A			Public Correspondence (Ship-to-Shore Duplex) Port Operations
67	156.375	160.975	UK Small Ship Safety Channel			Working Channel, Marine Weather	Maritime Radio Working Channel	A  VTS (Ship-to-ship + Port Operations)
68	156.425	161.275		Non-commercial  A			Maritime Radio Working Channel	A  Port Operations
69	156.475	161.075	Port Operations	Non-commercial  A		Australian Navy	Maritime Radio Working channel Surf Lifesaving	A  Ship-to-ship Port Operations
70	156.525	161.125	Digital Selective Calling  A
71	156.575	161.175		Non-commercial  A			Maritime Radio Working Channel	A  VTS (Ship-to-ship + Port Operations) Port Operations
72	156.625	161.225	Ship-to-ship  A	Non-commercial ship-to-ship  A	Ship-to-ship			A  Ship-to-ship Ship-to-air
73	156.675	161.275	HM Coastguard Safety Broadcasts			Ship-to-ship	Marinas - Working	A  Ship-to-ship Ship-to-air (Port Operations)
74	156.725	161.325	British Waterways Channel (Canal System)			Ship-to-ship	Working - Coast/Ship	A  Port Operations
75	156.775	161.375	Navigaton related communicatins (limited to 1 watt)					A Restricted Ship-to-ship Port Operations
76	156.825	161.425						A  Restricted Port Operations
77	156.875	161.475	Ship-to-ship  A			Ship-to-ship		A  Ship-to-ship
78	156.925	161.525		Non-commercial  A				Public Correspondence (Ship-to-Shore Duplex) Port Operations
79	156.975	161.575						Public Correspondence (Ship-to-Shore Duplex) Port Operations
80	157.025	161.625	UK Marina Channel			Repeater Operations	Coastguard Radio - Working Channel	GOFREP on Gulf of Finland Public Correspondence (Ship-to-Shore Duplex) Port Operations
81	157.075	161.675		A  U.S. Government Use Only		Repeater Operations	Coastguard Radio - Working Channel	GOFREP (Estonia) on Gulf of Finland Public Correspondence (Ship-to-Shore Duplex) Port Operations
82	157.125	161.725		A  U.S. Government Use Only	Canadian Coast Guard - Working Channel		Coastguard Radio - Working Channel	Public Correspondence (Ship-to-Shore Duplex) Port Operations
83	157.175	161.775		A  U.S. Coast Guard Use Only	Continuous Marine Broadcasts  B  (WX 9)			Public Correspondence (Ship-to-Shore Duplex) Port Operations
84	157.225	161.825	HM Coastguard Maritime Safety Information				Coastguard Radio - Working Channel	Public Correspondence (Ship-to-Shore Duplex) Port Operations
85	157.275	161.875	UKSAR TWC (simplex)		Radio Telephone - Duplex		Coastguard Radio - Working Channel	Public Correspondence (Ship-to-Shore Duplex) Port Operations
86	157.325	161.925	HM Coastguard Maritime Safety Information				Coastguard Radio - Working Channel	Public Correspondence (Ship-to-Shore Duplex) Port Operations
87	157.375	161.975	Automatic Identification System  B
88	157.425	162.025	Automatic Identification System  B

Notes:

1: Some radios enable channels 3A, 61A, and 64A when configured for "USA mode" even though those channels are not listed for maritime use by the US Coast Guard or by the FCC. The frequencies in question appear to be used for land-mobile communication by police and fire departments in some US Cities.

2: Channel 22A is reserved for communication between the U.S. Coast Guard vessels and private vessels. The Coast Guard does not monitor 22A: Contact must first be established on 16.

3: UKSAR land based search & rescue teams have access to the simplexed versions of 24, 62, 63, 64, 85 for operational & training needs. These include Mountain Rescue teams in England, Wales & Scotland.

4: CCG public operations moved from 22A to 04A to avoid interference from USCG stations in northern Washington state.

See also

• 2182 kHz
• AIS System
• Maritime mobile amateur radio
• Radio horizon

References

1. ^ ^{a b c} UK Maritime and Coastguard Agency Marine Guidance Note MGN324
2. ^ VHF Radio (including GMDSS) (2nd ed.). RYA. 2008. ISBN 978-1-906435-20-2. 
3. ^ Kommunikationsverket 2010: Handbok i VHF-radiokommunikation för radiooperatör med kusttrafikcertifikat

External links

• US Coast Guard basic radio information for boaters
• Coast Guard marine channel listing (with frequencies)
• US FCC marine channel listing (by function)
• UK MCA advice on use of VHF at sea, including collision avoidance, effective ranges, and International channel usage*
• Canadian VHF Bands in the Maritime Service
• VHF Marine Band Plan in TURKEY (Türkiye'deki VHF Deniz Telsiz Frekans Kanal Listesi)
• Listen LIVE! VHF Marine Radio @ East of Izmit Bay / TURKEY (İzmit Körfezi Doğusu - Canlı VHF Marin Telsiz Dinleme)
• New Zealand VHF Radio Resource Center
• Australian VHF Radio Network locations and How to Make A Distress Call