VHF radio is mostly useful for line-of-sight operation, and as such it has a direct range of around 25 miles. Repeater operation with shore stations in elevated positions may expand that range considerably. Some modern VHF radios also have inbuilt Automatic Identification System (AIS) capability, allowing the user to view the location of other vessels within the immediate horizon as a sort of "poor man's radar". Since ships over 300 tons - and some fishing fleets - are now required to have an AIS transponder running at all times, this safety feature should reduce maritime collisions.
It is the preferred radio for use in port, and power should be reduced close to shore to avoid interference. To this end modern radios have a Hi-Lo power switch. Maximum output is generally 25W with low power setting being somewhere from 1W to 5W.
Other useful features include the ability to monitor the emergency channel (Ch 16) while being tuned to another operating channel, which is called "dual watch" capability.
It should be carefully noted that many VHF radios from the USA were built to an inferior AIS "standard" that only monitors a single AIS channel. It is now illegal to sell, import or manufacture such radios. Buyers should therefore be careful of "bargain" radios of US origin.
- Radio Calling Procedure applies to both VHF Radio and HF Radio
- General Marine VHF Radio Operating Procedures
- VHF Distress Calling Procedures (MAYDAY, PAN-PAN and SECURITE)
- Care and Maintenance of Batteries
Also see the FCC Website (covers HF Marine Radio as well)
Order of Priority of Communications in Maritime Mobile Service
- Distress calls, distress messages and distress traffic (MAYDAY).
- Communications preceded by the urgency signal (PAN-PAN).
- Communications preceded by the safety signal (SECURITE).
- Communications relating to radio direction finding.
- Communications relating to the navigation and safe movements of aircraft engaged in search and rescue operations.
- Communications relating to the navigation, movements and needs of ships and weather observation messages destined for an official meteorological service.
- Government radiotelegrams relative to the application of the United Nations Charter (ETATPRIORITENATIONS)
- Government radiotelegrams with priority and government calls for which priority has been expressly requested (ETATPRIORITE)
- Service communications relating to the working of the telecommunication service or to communications previously exchanged, e.g. service telegrams.
- Government communications other than those shown ordinary private communications, RCT radiotelegrams (telegrams concerning persons protected in time of war by the Geneva Conventions of 12 August 1949) and press radiotelegrams.
- The navigation warning should then be re-announced and broadcasted on the working frequency which was announced on the calling frequency.
Navigation warnings broadcasted by shipstations are usually intercepted and relayed by the responsible coast stations but when necessary the shipstations should repeat their navigation warnings at suitable intervals, e.g. when towing another vessel or when the responsible coast station has not acknowledged receipt.
Marine VHF Frequencies & Channels
VHF CHANNELS & FREQUENCIES AND THEIR USE
The following table is correct for the USA only, and varies from ITU (International) standards. Most newer VHF radios have the capability to switch between "US" and "INT" mode. Both New Zealand and Canada use a variant system requiring special channel spacings. The NOAA weather frequencies listed are only available off mainland USA.
The channel numbers run from 01A to 88A in the left hand column. The frequencies in megahertz (MHz) are given for each designated channel, first the transmit MHz then the receive MHz. Against each channel is the authorised use for that channel. These are the channels found in most VHF marine radios marketed today - some earlier models will not have all channels and frequencies available.
|01A||156.050||156.050||Port Operations and Commercial, VTS. Available only in New Orleans / Lower Mississippi area.|
|05A||156.250||156.250||Port Operations or VTS in the Houston, New Orleans and Seattle areas.|
|08||156.400||156.400||Commercial (Intership only)|
|09||156.450||156.450||Boater Calling. Commercial and Non-Commercial.|
|11||156.550||156.550||Commercial. VTS in selected areas.|
|12||156.600||156.600||Port Operations. VTS in selected areas.|
|13||156.650||156.650||Intership Navigation Safety (Bridge-to-bridge). Ships >20m length maintain a listening watch on this channel in US waters.|
|14||156.700||156.700||Port Operations. VTS in selected areas.|
|15||--||156.750||Environmental (Receive only). Used by Class C EPIRBs.|
|16||156.800||156.800||International Distress, Safety and Calling. Ships required to carry radio, USCG, and most coast stations maintain a listening watch on this channel.|
|20||157.000||161.600||Port Operations (duplex)|
|21A||157.050||157.050||U.S. Coast Guard only|
|22A||157.100||157.100||Coast Guard Liaison and Maritime Safety Information Broadcasts. Broadcasts announced on channel 16.|
|23A||157.150||157.150||U.S. Coast Guard only|
|24||157.200||161.800||Public Correspondence (Marine Operator)|
|25||157.250||161.850||Public Correspondence (Marine Operator)|
|26||157.300||161.900||Public Correspondence (Marine Operator)|
|27||157.350||161.950||Public Correspondence (Marine Operator)|
|28||157.400||162.000||Public Correspondence (Marine Operator)|
|63A||156.175||156.175||Port Operations and Commercial, VTS. Available only in New Orleans/Lower Mississippi area.|
|67||156.375||156.375||Commercial. Used for Bridge-to-bridge communications in lower Mississippi River. Intership only.|
|70||156.525||156.525||Digital Selective Calling (voice communications not allowed)|
|72||156.625||156.625||Non-Commercial (Intership only)|
|77||156.875||156.875||Port Operations (Intership only)|
|79A||156.975||156.975||Commercial. Non-Commercial in Great Lakes only|
|80A||157.025||157.025||Commercial. Non-Commercial in Great Lakes only|
|81A||157.075||157.075||U.S. Government only - Environmental protection operations.|
|82A||157.125||157.125||U.S. Government only|
|83A||157.175||157.175||U.S. Coast Guard only|
|84||157.225||161.825||Public Correspondence (Marine Operator)|
|85||157.275||161.875||Public Correspondence (Marine Operator)|
|86||157.325||161.925||Public Correspondence (Marine Operator)|
|AIS 1||161.975||161.975||Automatic Identification System (AIS)|
|AIS 2||162.025||162.025||Automatic Identification System (AIS)|
|88A||157.425||157.425||Commercial, Intership only.|
NOAA Weather Radio Frequencies
See the NOAA Weather Radio Homepage for more information.
Channel 16, 156.800MHz, is the international maritime distress frequency on VHF. This channel is also used for calling other vessels but you are expected to move your discussion to another channel after contact is made. Have a frequency in mind when calling another station.
The United States Coast Guard generally utilizes channel 22A, 157.100MHz, as its working channel although when establishing contact with them you should pay attention to the channel given to you by the Coast Guard station.
Channel 70 is also used as an international distress and calling channel for DSC. This channel is not used in conjunction with voice communications. Your radio should prompt you for a voice channel to move to before calling a station. If used for distress your radio should automatically switch to channel 16 after transmitting your digital distress signal on channel 70.
- Ensure that the power supply is switched on.
- Check that the voltage is correct.
- Check that the transmitter and receiver are on the correct frequencies.
- Check that the correct modes have been selected e.g. A3 A3H A3A A3J.
- Check that the aerial/aerials is/are connected.
- Check that the aerial/aerials is/are up and are not shorting anywhere.
- Check all switches and visible connections.
- Check fuses.
- If voltage is low check flat batteries and recharge.
- If voltage is correct but transmitter won't tune up check aerials and fuses.
- If transmitter tunes up OK and you are unable to establish communication check that you are calling and listening on the correct frequencies. When calling always say where you are listening.
- Try alternative aerial if available e.g. for portable lifeboat radio. Check that artificial aerial is disconnected.
- If your transmitter is working satisfactory but you cannot establish communication check that you are within range of the station you are calling.
- John C. Payne, Marine Electrical & Electronics Bible, Sheridan House, ISBN 1574090607
List links to discussion threads on partnering forums. (see link for requirements)
- VHF on wikipedia
- GMDSS on wikipedia
- DSC on wikipedia
- ITU search engine to retrieve a vessel's information by name, call sign, MMSI, EPIRB id.
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