Marine VHF radio

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A VHF set and a VHF channel 70 DSC set, the DSC on top
A standard handheld maritime VHF, mandatory on larger seagoing vessels under the GMDSS rules
A classic maritime VHF set
File:SP3540.jpg
A portable VHF which is ip67, GMDSS and ATEX approved

Marine VHF radio refers to the radio frequency range between 156.0 and 162.025 MHz, inclusive. In the official language of the International Telecommunication Union the band is called the VHF maritime mobile band.

Marine radio equipment is installed on all large ships and most seagoing small craft. It is also used, with slightly different regulation, on rivers and lakes. 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 very high frequency (VHF) range, between 156 and 162.025 MHz. Although it is widely used for collision avoidance, its use for that 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. 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; 6 mi) between aerials mounted on small boats at sea level.[1] Frequency modulation (FM) is used, with vertical polarization, meaning that antennas have to be vertical in order to have good reception.

Modern-day marine VHF radios offer not only basic transmit and receive capabilities. Permanently mounted marine VHF radios on seagoing vessels are required to have certification of some level of "Digital Selective Calling" (DSC) capability, to allow a distress signal to be sent with a single button press.

Marine VHF mostly uses "simplex" 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. Some channels, however, are "duplex" transmission channels where communication can take place in both directions simultaneously when the equipment on both ends allow it (full duplex), otherwise "semi-duplex" is used.[1] Each duplex channel has two frequency assignments. Duplex channels can be used to place calls on the public telephone system for a fee via a marine operator. When full duplex is used, the call is similar to one using a mobile phone or landline. When semi-duplex is used, voice is only carried one way at a time and the party on the boat must press the transmit button only when speaking. This facility is still available in some areas, though its use has largely died out with the advent of mobile and satellite phones. Marine VHF radios can also receive weather radio broadcasts, where they are available.

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 waterproof 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 (MMSI). The DSC information is sent on the reserved Channel 70. When the receiver picks up the call, their 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 used for seagoing vessels and consists of 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
  • Coastal station : 00 – e.g. Solent Coastguard : 002320011
  • Group of stations : 0 – e.g. 023207823
  • Portable DSC equipment : for UK 2359 - e.g. 235900498

For use on the inland waterways within continental Europe, a compulsory Automatic Transmitter Identification System (ATIS) transmission conveys the vessel's identity after each voice transmission. This is a ten-digit code that is either an encoded version of the ship's alphanumeric call sign, or for vessels from outside the region, the ship MMSI prefixed with '9'. The requirement to use ATIS in Europe, and which VHF channels may be used, are strongly regulated, most recently by the Basel agreements.

Channels and frequencies

Simplex channels here are listed with the A and B frequencies the same. The frequencies, channels, and some of their purposes are governed by the ITU. For an authoritative list see.[2] The original allocation of channels consisted of only channels 1 to 28 with 50 kHz spacing between channels, and the second frequency for duplex operation 4.6 MHz higher. Improvements in radio technology later meant that the channel spacing could be reduced to 25 kHz with channels 60 to 88 interspersed between the original channels. Channels 75 and 76 are omitted as they are either side of the calling and distress channel 16, acting as guard channels. The frequencies which would have been the second frequencies for simplex channels are not used for marine purposes and can be used for other purposes that vary by country. For example 161.000 to 161.450 MHz are part of the allocation to the Association of American Railroads channels used by railways in the USA and Canada.[3]

Channel
number		 Frequencies (MHz)  United Kingdom [4]  United States  Canada  Australia  New Zealand  Finland[5]
 A 
Usually ship stations		  B 
Usually coast stations
0 156.000 160.600 Private, coast guard  A 
1 156.050 160.650 Ship-to-ship/shore, commercial and safety
West Coast  A 
 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
6 156.300 156.300 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
8 156.400 156.400 Ship-to-ship  A  Ship-to-ship
East and west coasts,
Lake Winnipeg  A 		 Working - Intership Working - Intership  A  Ship-to-ship
9 156.450 156.450 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
10 156.500 156.500 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
11 156.550 156.550 Port Operations VTS - BC Coast
Pilotage  A 		 Port Operations  A  Port Operations
12 156.600 156.600 Port Operations VTS - San Francisco offshore
Pilotage  A 		 VTS - BC Coast
Port and pilot ops  A 		 Port Operations, VTS Port Operations  A  Port Operations
13 156.650 156.650 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
14 156.700 156.700 Port Operations VTS - San Francisco Bay and Delta
Pilotage  A 		 VTS - BC Coast
Port and pilot ops  A 		 Port Operations  A  Working channel for SAR authorities, Turku Radio
(Port Operations)
15 156.750 156.750 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 

All vessels equipped with VHF must maintain watch.
17 156.850 156.850 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 and 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 National Coastwatch Working Channel for communication with local mariners for radio checks and local sea conditions. Effective 1st October 2014. 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
67 156.375 156.375 UK Small Ship Safety Channel Working Channel, Marine Weather Maritime Radio Working Channel  A  VTS
(Ship-to-ship + Port Operations)
68 156.425 156.425 Non-commercial  A  Maritime Radio Working Channel  A  Port Operations
69 156.475 156.475 Port Operations Non-commercial  A  Australian Navy Maritime Radio Working channel
Surf Lifesaving		  A  Ship-to-ship
Port Operations
70 156.525 156.525 Digital Selective Calling  A 
71 156.575 156.575 Non-commercial  A  Maritime Radio Working Channel  A  VTS
(Ship-to-ship + Port Operations) Port Operations
72 156.625 156.625 Ship-to-ship  A  Non-commercial ship-to-ship  A  Ship-to-ship  A  Ship-to-ship
Ship-to-air
73 156.675 156.675 HM Coastguard Safety Broadcasts Ship-to-ship Marinas - Working  A  Ship-to-ship

Ship-to-air
(Port Operations)
74 156.725 156.725 British Waterways/Canal and River Trust Channel (Canal and River System) Ship-to-ship Working - Coast/Ship  A  Port Operations
75 156.775 156.775 Navigation related communications (limited to 1 watt)  A Restricted
Ship-to-ship
Port Operations
76 156.825 156.825  A  Restricted
Port Operations
77 156.875 156.875 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
86 157.325 161.925 HM Coastguard Maritime Safety Information Coastguard Radio - Working Channel Public Correspondence (Ship-to-Shore Duplex)
Port Operations
87 157.375 157.375 Public Correspondence
Port Operations
88 157.425 157.425 Commercial, Intership only.
87B 161.975 161.975 Automatic Identification System  B 
88B 162.025 162.025 Automatic Identification System  B 

[6] Notes:

  1. Some radios enable channels 3A, 61A, and 64A when configured for "USA mode" even though those channels are allocated exclusively for Public Safety use by the FCC. The frequencies 156.075, 156.150, and 156.225 MHz are used for interoperability communication by police and fire departments in many areas.
  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 and rescue teams have access to the simplexed versions of 24, 62, 63, 64, 85 for operational and training needs. These include mountain rescue teams in England, Wales and Scotland.
  4. CCG public operations moved from 22A to 04A to avoid interference from USCG stations in northern Washington state.

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 "Sécurité" 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 (local language is used for some of these, when talking to local stations)
  • 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 or a combination of English and Roman languages: Wun, Too, Tree, Fow-er, Fife, Six, Sev-en, Ait, Nin-er, Zero, Decimal, alternatively in marine communication: unaone, bissotwo, terrathree, kartefour, pantafive, soxisix, setteseven, oktoeight, novenine, nadazero

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

See also

References

  1. ↑ 1.0 1.1 1.2 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Circular letter CM/19-E, International Telecommunications Union, 27 March 2009
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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