February 12, 2019

Marine VHF Radio Overview

FUNCTIONALITIES

Digital Selective Calling

VHF radios feature Digital Selective Calling (DSC) which has both non-emergency and emergency functionality. DSC allows a boater to send their current location to another boater within range. In addition, it serves as a highly important resource in emergency situations. With a single-touch button, the radio will send a digital Mayday notification on channel 70, which automatically gets picked up by the Coast Guard and all other vessels within range. Your MMSI number, exact location, and the nature of the emergency is also sent. From there, your radio will automatically switch to channel 16 which provides a direct communication line with rescue services.

Safety and Navigation

Pleasure-only boaters use channels 6 and 22A for mainly safety reasons. Channel 6 is reserved for search and rescue operations between local vessels. The Coast Guard will ask the boater to switch to channel 22A after making contact on channel 6.

Channel 13 serves as a navigational resource between watercraft. This channel is mostly used by larger vessels to disclose their current location and where they are headed. It is also used for bridge and lock communication.

Weather Alerts

VHF radios incorporate automatic weather alerts. An alert will be sent when the NOAA issues a special weather warning. Thunderstorms, tornadoes, hurricanes, and other severe weather conditions will signal an alert.

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HOW THEY WORK

Channels

Each VHF radio operates on 55 channels within the United States, Canada, and international waters. Most are used for commercial shipping and Coast Guard use; however, pleasure-only boaters can transmit on approximately 12-15 channels.

You can set up “favorite” channels to constantly scan while navigating. It is good practice to set up at least channels 9 and 16 and monitor them at all times.

Sight Signals

Marine VHF radios both transmit and receive through line of sight signals. Therefore, any mountainous terrain, land masses, or other obstructions will temporarily block VHF signals.

Maximum Power

This radio is legally bound to 25 watts of transmit power.

Antenna

When installing your VHF, mount your antenna as high as possible on the watercraft.

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VHF Radio Options