BlueSeas

United States VHF Marine Radio Frequencies

U.S. VHF Frequency and Usage Table

Currently in the U.S. there are approximately 49 VHF channels available plus 7 additional channels dedicated to NOAA WX Radio and (2) for use of the Automatic Identification System (AIS.) Many of these channels are dedicated to specific uses and therefore are unavailable for routine traffic. Here is a quick look at the disparity between commercial/government operators and the non-commercial recreational boating community:

Useful Frequencies for the Boater

Let’s look at the channels / frequencies that are of interest to the recreational boater. These are comprised of the 5/7 non-commercial, 7 weather, 9 public correspondence, plus a number of the special usage frequencies.

Complete List of U.S. VHF Frequencies and Usage

The complete list can be downloaded in zipped PDF format United States VHF Frequency Chart.

Many NOAA Weather Radio receivers are also programmed for three additional frequencies; 161.650 MHz (marine VHF Ch 21B), 161.775 MHz (marine VHF Ch 83B) and 163.275 MHz. The first two frequencies are used by Canada for marine weather broadcasts. 163.275 MHz was used by the National Weather Service for internal coordination in the event of a power outage but is no longer in active use.

Why are some channels now (4) digits long?

Due to the increased need of more marine VHF channels for VTS, commercial requirements, and port operations, a recent ITU World Radio Conference has authorized and developed a new channel plan for the VHF marine radio frequencies. This new channel plan took effect January 1, 2017.

While these changes will affect all users worldwide, the types and amount of change will vary with the country involved.

What changes will we see in the United States?

Originally all marine VHF frequencies were (2) digits only and most were codified as duplex channels. Some nation states in the past (including the U.S.) had decided to use some of these duplex channels as simplex channels. This was done by splitting off one of the duplex frequency pairs, and using that as a simplex channel. An Alphabetical letter designator was then assigned to the frequency to show which of the frequency pairs were being used. The "A" (or Alpha) signified that the ship transmit frequency was being used, while "B" (or Bravo) meant that the coast transmit (ship receive) frequency was being used.

A good example of this is Channel 22A, which most boaters are familiar with. Originally, under ITU Regulations, channel 22 is a duplex channel with the frequencies 157.100/161.700 assigned to it.

Here in the U.S. it was decided to split this frequency so that it could be used for both ship to ship and ship to shore communications as a simplex frequency. The ship transmit side of channel 22 (157.100 MHz) was chosen resulting in the new channel becoming 22A. Had they chosen to use the coast transmit frequency the new channel would have become 22B. Pretty simple really, not to mention it is the system that most of us have grown up with.

So now, enter the "International Telecommunication Union" (ITU):
A United Nations Organization.

The UN is going to get involved! - How lucky can we be?
(Hopefully you didn’t miss the sarcasm there.)

So the ITU decided that for some reason, the letter designators were somehow inferior. So they dreamed up a new system for these split channels. The ITU, in all of its wisdom, has decided to drop the letter designators and institute a (4) digit channel numbering scheme to show frequencies that have been split from duplex to simplex.

They decided that if the "Ship Transmit" frequency was to be used then the basic channel number would be preceded by a "10" and if the "Coast Transmit" frequency is being used, to precede it with a "20." So, what used to be "Channel 22A" is now "Channel 1022." In Canada, where they often use the "Coast Transmit" side of duplex frequencies, such as their use of "Channel 21B"; the new channel designator will now be "Channel 2021."

Seems to me they have taken the "Simple out of Simplex" and replaced it with "Complex." But hell, what do I know?

ICOM M424G

ICOM M424G VHF Marine Radio

The ICOM M424G is full-featured, compact, rugged. and built for the harsh marine environment. Waterproof and submersible for up to 30 minutes. Built-in noise cancelling reduces background noise to up to 90%. The menu system provides intuitive operation. The public address and foghorn capabilities. The built-in DSC watch function monitors Ch. 70 (DSC channel) activity. DSC functions include: distress, individual, group, all ships, urgency, safety, and DSC test calls. Internal GPS receiver, current position and time are shown on the IC-M424G's display. When receiving position information from another vessel, the IC-M424G can transfer it to a navigational device via NMEA 0183 connectivity.