Marine VHF Frequencies: The Basics

If you’re new to the world of marine radio, the VHF frequencies can seem like a confusing jumble of numbers. But don’t worry, it’s not as complicated as it looks. 

Marine VHF frequencies are used for communication between boats and between boats and shore stations. They're also used for distress calls and other emergency situations.

 

In this article, we’ll give you a quick overview of the most important marine VHF frequencies and what they’re used for. Stick around to learn how marine VHF frequencies are regulated and how you can use them effectively. 

What Are VHF Marine Frequencies?

The VHF marine frequencies are a set of international radio frequencies used for communications between ships, boats, and shore stations. These frequencies are in the very high frequency (VHF) range and are between 156.0 MHz and 174.0 MHz (VHF marine band).

Marine VHF radios are programmed with specific frequencies for different purposes, such as ship-to-ship communication, ship-to-coast communication, and distress calls.

These frequencies are divided into channels, each of which is designated for a specific purpose. 

The channels in the marine VHF band are divided into two categories:

  • Simplex channels are used for point-to-point communication between two radios.
  • Duplex channels are used for communication between a radio and a marine VHF repeater. 

A marine VHF repeater is a device that receives a signal on one frequency and retransmits it on another frequency. This allows for longer-range communication.

All channels except those reserved for emergency communications may be modulated either with single or double sidebands. This is because they need to be easily heard and understood by those who are trying to communicate.

 

Standard Marine VHF Frequencies and Their Use

The standard VHF marine frequencies are used for ship-to-ship and ship-to-shore communications, as well as for distress signals.

The most common marine VHF frequencies are 156.800 MHz for channel 16 (the international distress channel), 156.650 MHz for channel 9 (the calling channel for recreational boaters), and 156.725 MHz for channel 6 (the inter-ship safety communications channel).

Other common VHF marine frequencies include channels:

  • Channel 12 (156.600 MHz)- Regulating vessel traffic.
  • Channel 13 (156.650 MHz)- Bridge-to-bridge communications.
  • Channel 22A (157.100)- Ship-to-shore communications. 
  • Channel 67(156.375 MHz)- Safety channel for small ships.
  • Channel 70 (156.525 MHz)- Automatic distress alert.

In addition to these common channels, there are a variety of other VHF marine frequencies that are used for specific purposes such as weather broadcasts, navigational aids, and marine safety information.

Please note: VHF marine frequencies can vary depending on the country in which you are sailing. 

Marine VHF Frequencies: Programming and Regulation

The marine VHF radio system uses a system of radio frequencies that are assigned to specific channels. In terms of regulation, these channels are divided into two main groups: the international calling and distress frequencies, and the national channels. 

The international calling and distress frequencies are used for emergency communications and are monitored by the Coast Guard. The national channels are used for general communications between ships and land stations.

In Canada, the Department of Innovation, Science and Economic Development Canada (ISED) regulates marine VHF frequencies. In the United States, the Federal Communications Commission (FCC) regulates marine VHF frequencies. 

The international (standard) VHF marine radio frequencies are heavily regulated by international treaties and agreements, and the use of these frequencies is generally limited to maritime communications.

The marine VHF frequencies are programmed into radios using a process called channelizing. Channelizing is the process of assigning a specific frequency to each radio channel. 

This ensures that only radios that are programmed with the correct frequencies can communicate with each other.

How to Use Marine VHF Frequencies Effectively

To use marine VHF frequencies effectively, you need to have a clear understanding of the different frequencies that are available and how they are used. You also need to be aware of the range of each frequency and the limitations of each. 

To get this information, search for an online table of frequency allocations in your area. 

The most important thing to remember when using marine VHF frequencies is to always listen first before transmitting. This will help to avoid interference with other users and will allow you to hear any important information that may be coming through on the frequency.

You also need to have proper marine VHF equipment. This includes an installed and functioning antenna, enough batteries, and a primary and backup radio. 

Here are other tips to consider when using marine VHF frequencies:

  • Monitor the weather conditions frequently and adjust your plans accordingly.
  • Make sure your VHF radio is turned on and working properly before setting out.
  • Know the proper marine VHF frequencies to use for distress calls and other purposes.
  • Speak clearly and slowly when using the VHF radio.
  • Follow all the rules and regulations for using marine VHF frequencies in your area.

FAQs

What channel should I keep my VHF radio on?

If you are pleasure boating and not communicating with another station, you should keep your VHF radio on channel 9 or channel 16. This is a requirement by many national regulatory bodies such as the Federal Communications Commission. 

By keeping your radio on one of these channels, you will be able to hear any distress calls that may come in. Additionally, other boaters will be able to reach you if they need to.

What is the difference between marine VHF frequencies and VHF channels?

VHF frequencies are the frequencies that are used by the VHF radio waves, while VHF channels are the specific frequencies that are assigned to specific uses.

Can amateur radio broadcast on marine VHF frequencies

Yes, in most countries amateur radio operators are allowed to install and use amateur radio equipment on boats. There may be some restrictions on the power output and type of antenna that can be used, but in general amateur radio equipment can be used to broadcast on VHF frequencies.

Do marine VHF frequencies have any limitations

VHF marine radio communications can be affected by atmospheric conditions, so they are not always reliable. In addition, VHF marine radio signals can only travel a limited distance (about 60 nautical miles), so they are not suitable for very long-distance communications.