Frequencies approve by ITU have been given channel numbers.
The marine frequency band for VHF radio communication, extending between 156 MHz and 174 MHz, contains 57 individual VHF CH (channels) numbered consecutively from VHF CH 1 to VHF CH 28 and from VHF CH 60 to VHF CH 88.
VHF Channel 70: For DSC only – no voice transmission allowed! Distress, Urgency, Safety and Routine Alerting – This channel must not be used for RT communications.
VHF CH 16: RadioTelephony Distress, Urgency, Safety and Routine Calling – is exclusively available for RadioTelephony Distress, Urgency, Safety and Routine Calling only.
VHF CH13: is an inter-ships channel reserve bridge-to-bridge communication on matters of navigational safety.
Public correspondence – CRS (Coast Radio Stations) – to interface between boats at sea with the main shore based telecommunications networks; provide facilities for testing VHF radios; transmitting weather forecasts, broadcasts and navigational warnings and coordinating SAR; coordinate Maritime or Medical Advice or Assistance; receive boat voyage reports on leaving or entering port and ETA (Estimated Time of Arrival), so on and so forth.
CG (Coast Guards) channel – may provide the same facilities as CRS with the exception of interfacing with main shore based telecommunications networks, in coastal regions where there are no CRS established.
VHF CH 11,12,14: Port Operations – provide radio communication services in harbour with port operators, pilot vessels, tugs, pilot stations and all associated VTMS (Vessel Traffic Management Services). It would be physically possible for two boats to communicate on Channel 12 but it would be illegal to do so.
VHF CH 15, 17, 69: Ship movement – similar to port operations.
VHF Channel 6, 8, 72, 77 : Inter-ship – used for radio communication between ships at sea.
On Board Communication channel– used for on board radio communications using handheld VHF.
Boat Marinas channels– provide availability of moorings, recommendations for sailing into port and harbour facilities and so forth. Irish marinas use VHF CH 80 channel. Dedicated VHF channels are available for particular geographical areas, for example CH M (157.850 MHz) and CH M2 (161.425 MHz) are “private” channels that have been allocated by the UK government specifically for use by marinas, yacht clubs and pleasure craft.
MSI (Maritime Safety Information) channel – this includes weather forecasts and broadcasts, navigational warnings and SAR information. Normally transmitted by RT to all stations by either shore based CRS or CG on working channels either at regular published times or indicated by initial alerting by DSC on VHF CH 70.
SAR (Search And Rescue) channel – used for search and rescue and anti-pollution operations. VHF CH 67 has been allocated in Ireland for the Coast Guard to communicate with its own assets (helicopters, rescue boats) during SAR incidents and training.
All vessels equipped with VHF must maintain listen watch! It is so important that channel 16 should not suffer any interference!
Calls on Channel 16 should be kept to a minimum, and part from distress and safety calls, must never longer than one minute.
it measn that allows it to be used only by the holder! Do not use it!
VHF CH 0 and 00: A private channel, designated in UK for Search and Rescue organisations and Coast Guard.
M (often 32), M2 (is called P1 or P4): UK private channels dedicated to marinas, yacht clubs, and recreational craft. It’s should be used only in UK waters. Other countries have allocated it for different purpose.
A few countries, including USA do not conform to the international channel designation and usage. Some duplex channels will be simplex, and for other purposes. So make sure you are not using the wrong system by mistake.
When you are using one frequency, you can do only one action: to receive or to transmit. It’s impossible to do both. So single frequency channel is known as simples.
Simplex is the communication method where both transmitter and receiver are operating on a single or the same frequency.
The two-way communication with two frequencies operation is known as duplex, two frequencies channel is a duplex channel. On duplex channels it is possible to transmit and receive simultaneously like over a normal telephone.
With duplex channels our transmission can only be heard by the CRS. However, all ship stations listening to the same channel can hear the CRS transmission.
VHF CH | Simplex/
Duplex |
The purpose of the Channel | VHF CH | Simplex/
Duplex |
The purpose of the Channel |
01 | D | Public Correspondence | 60 | D | Public Correspondence |
02 | D | Public Correspondence | 61 | D | Public Correspondence |
03 | D | Public Correspondence | 62 | D | Public Correspondence |
04 | D | Public Correspondence | 63 | D | Public Correspondence |
05 | D | Public Correspondence | 64 | D | Public Correspondence |
06 | S | Inter-ship
& Aero SAR |
65 | D | Public Correspondence |
07 | D | Public Correspondence | 66 | D | Public Correspondence |
08 | S | Inter-ship | 67 | S | Coast Guard |
09 | S | Inter-ship | 68 | S | Port Operations |
10 | S | Inter-ship
& SAR |
69 | S | Inter-ship |
11 | S | Port Operations | 70 | S | DSC Distress, Urgency, Safety & Routine Alerting |
12 | S | Port Operations | 71 | S | Port Operations |
13 | S | Inter-ship Navigational Safety (Bridge-to-bridge)
& Port Operations |
72 | S | Inter-ship |
14 | S | Port Operations | 73 | S | Inter-ship
& SAR |
15 | S | On Board Communications
(Max Power 1 watt) |
74 | S | Port Operations |
16 | S | RT Distress, Urgency, Safety & Routine Calling | 75 | S | Restricted to navigation-related communication only |
17 | S | On Board Communications
(Max Power 1 watt) |
76 | S | Restricted to navigation-related communication only |
18 | D | Public Correspondence | 77 | S | Inter-ship |
19 | D | Public Correspondence | 78 | D | Public Correspondence |
20 | D | Public Correspondence | 79 | D | Public Correspondence |
21 | D | Public Correspondence | 80 | D | Marinas |
22 | D | Public Correspondence | 81 | D | Public Correspondence |
23 | D | Public Correspondence | 82 | D | Public Correspondence |
24 | D | Public Correspondence | 83 | D | Public Correspondence |
25 | D | Public Correspondence | 84 | D | Public Correspondence |
26 | D | Public Correspondence | 85 | D | Public Correspondence |
27 | D | Public Correspondence | 86 | D | Public Correspondence |
28 | D | Public Correspondence | 87 | S | Port Operations |
88 | S | Port Operations |