ScannerDesk - VA3DBJ

Marine VHF radio is installed on all large ships and most motorized small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours 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.

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. Frequency modulation is used.

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. The majority of channels, however, are set aside for "duplex" 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 system for a fee via a marine operator. This facility is still available in some areas, though its use has largely died out. In Canadian and U.S. waters, Marine VHF radios can also receive weather radio broadcasts, where they are available, on receive-only channels wx1, wx2, etc.

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

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.

Channels marked (CCG) or (USCG) are for Canadian or US Coast guard authorized stations only. Channel 70 is reserved for selective calling distress and safety system.

The letters under "area" mean:

I: International only (non-US)
C: Canadian usage
A: American usage

Channels with an "A" suffix are simplex operation on the ship transmit frequency of an international duplex channel. Canada uses a "B" suffix to denote broadcast (one-way) use of the shore transmit side of an international duplex channel.

Vessel Traffic Services

Vessel Traffic Services are in place at several sites around the Great Lakes and the St. Lawrence River system. These stations are set up to provide mariners with traffic information to add to the safety of vessels when transiting cramped, high traffic water ways. The service requires vessels to call in at certain points and then relays that information to other vessels

St. Lawrence Seaway VTS

156.700 - Seaway Beauharnois Sector 1
156.600 - Seaway Eisenhower Sector 2
156.550 - Seaway Iroquois Sector 3 
156.650 - Seaway Clayton Sector 4 (St. Lawrence River portion)
156.650 - Seaway Sodus Sector 4 (Lake Ontario portion)
156.550 - Seaway Newcastle Sector 5
156.700 - Seaway Welland Sector 6
156.550 - Seaway Long Point Sector 7

Welland Canal

156.850 Upbound ship to lock  
156.325 Downbound ship to lock

HF On The Great Lakes

HF used by various shore stations around the lakes. With VHF and cellular phones these frequencies end up used most often to provide weather reports and notice to mariners broadcasts. Every great once-in-a-while you will hear a ship to shore phone call on them. All listed are upper side band unless otherwise noted.

Freq     Station 
2514.0 VCC Quebec CG Radio 
2550.0 WLC Rogers City MI 
2598.0 Canadian Coast Guard 
2582.0 WLC and various Canadian CG 
4369.0 WLC wx and some phone 
4381.0 WLC 
4408.0 WLC 
4143.5 Upper Lakes Shipping (Canada) 
6218.5 Upper Lakes Shipping (Canada) 
5692.0 US Coast Guard - Traverse City and Detriot Air Stations