Marine VHF radio
Overview
 
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
Rescue
Rescue refers to responsive operations that usually involve the saving of life, or prevention of injury during an incident or dangerous situation....

 services and communicating with harbours, locks
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

, bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

s and marina
Marina
A marina is a dock or basin with moorings and supplies for yachts and small boats.A marina differs from a port in that a marina does not handle large passenger ships or cargo from freighters....

s, and operates in the VHF
Very high frequency
Very high frequency is the radio frequency range from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted High frequency , and the next higher frequencies are known as Ultra high frequency...

  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.

A marine VHF set is a combined transmitter and receiver and only operates on standard, international frequencies known as channels
Channel (communications)
In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...

.
Encyclopedia
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
Rescue
Rescue refers to responsive operations that usually involve the saving of life, or prevention of injury during an incident or dangerous situation....

 services and communicating with harbours, locks
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

, bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

s and marina
Marina
A marina is a dock or basin with moorings and supplies for yachts and small boats.A marina differs from a port in that a marina does not handle large passenger ships or cargo from freighters....

s, and operates in the VHF
Very high frequency
Very high frequency is the radio frequency range from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted High frequency , and the next higher frequencies are known as Ultra high frequency...

  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.

A marine VHF set is a combined transmitter and receiver and only operates on standard, international frequencies known as channels
Channel (communications)
In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...

. 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 mile
Nautical mile
The nautical mile is a unit of length that is about one minute of arc of latitude along any meridian, but is approximately one minute of arc of longitude only at the equator...

s (111 km) between aerial
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...

s mounted on tall ships and hills, and 5 nautical mile
Nautical mile
The nautical mile is a unit of length that is about one minute of arc of latitude along any meridian, but is approximately one minute of arc of longitude only at the equator...

s (9 km) between aerials mounted on small boat
Boat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...

s at sea-level. Frequency modulation
Frequency modulation
In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

 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
Digital Selective Calling
Digital Selective Calling or DSC is a standard for sending pre-defined digital messages via the medium frequency , high frequency and very high frequency maritime radio systems. It is a core part of the Global Maritime Distress Safety System .-Workings:DSC was developed to replace a call in older...

" (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
Automatic Identification System
The Automatic Identification System is an automatic tracking system used on ships and by Vessel traffic services for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations...

 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
Duplex (telecommunications)
A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....

" transmissions channels where communication can take place in both directions simultaneously. 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
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

 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
Walkie-talkie
A walkie-talkie is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald L. Hings, radio engineer Alfred J. Gross, and engineering teams at Motorola...

 in design) can be carried on a kayak, or to a lifeboat
Lifeboat (shipboard)
A lifeboat is a small, rigid or inflatable watercraft carried for emergency evacuation in the event of a disaster aboard ship. In the military, a lifeboat may be referred to as a whaleboat, dinghy, or gig. The ship's tenders of cruise ships often double as lifeboats. Recreational sailors sometimes...

 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
Digital Selective Calling
Digital Selective Calling or DSC is a standard for sending pre-defined digital messages via the medium frequency , high frequency and very high frequency maritime radio systems. It is a core part of the Global Maritime Distress Safety System .-Workings:DSC was developed to replace a call in older...

" (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
Global Maritime Distress Safety System
The Global Maritime Distress and Safety System is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships, boats and aircraft....

 (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
    Maritime Mobile Service Identity
    A Maritime Mobile Service Identity is a series of nine digits which are sent in digital form over a radio frequency channel in order to uniquely identify ship stations, ship earth stations, coast stations, coast earth stations, and group calls...

     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
    Global Positioning System
    The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

     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
    United Kingdom
    The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

     – 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
    Mayday (distress signal)
    Mayday is an emergency procedure word used internationally as a distress signal in voice procedure radio communications. It derives from the French venez m'aider, meaning "come help me"....

    " distress call, the "Pan-pan
    Pan-pan
    In radiotelephone communications, a call of three repetitions of pan-pan is used to signify that there is an urgency on board a boat, ship, aircraft or other vehicle but that, for the time being at least, there is no immediate danger to anyone's life or to the vessel itself. This is referred to as...

    " urgency call and "Securité
    Securite
    When a marine radio transmission begins with "Sécurité, sécurité, sécurité" , it means that what follows is important safety information. The most common use of this is by coast radio stations before the broadcast of navigational warnings and meteorological information.It is normal practice to...

    " navigational hazard call.
  • using "pro-words
    Procedure word
    Procedure words or prowords are words or phrases limited to radio telephone procedure used to facilitate communication by conveying information in a condensed standard form. - OUT :...

    " based on the English language
    English language
    English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

     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
    English language
    English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

    : 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
Coast guard
A coast guard or coastguard is a national organization responsible for various services at sea. However the term implies widely different responsibilities in different countries, from being a heavily armed military force with customs and security duties to being a volunteer organization tasked with...

, enforcement away from the water is sometimes difficult.

Marine VHF Channels and Frequencies

Channel
number
Frequencies (MHz)
 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
Channel 16 VHF
Channel 16 VHF is a radio frequency on the marine VHF radio band. It is used for shipping and maritime purposes, to call up ships and shore stations, and as an international distress frequency. After an initial response the call is to be switched to one of the working channels, except in case of...

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 broadcast
Continuous marine broadcast
A continuous marine broadcast, or CMB, is a marine weather broadcasting service operated by the Canadian Coast Guard in both english and/or french...

s  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
Digital Selective Calling
Digital Selective Calling or DSC is a standard for sending pre-defined digital messages via the medium frequency , high frequency and very high frequency maritime radio systems. It is a core part of the Global Maritime Distress Safety System .-Workings:DSC was developed to replace a call in older...

  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
Automatic Identification System
The Automatic Identification System is an automatic tracking system used on ships and by Vessel traffic services for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations...

  B 
88 157.425 162.025 Automatic Identification System
Automatic Identification System
The Automatic Identification System is an automatic tracking system used on ships and by Vessel traffic services for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations...

 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.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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