The VHF radio set is the most ubiquitous piece of equipment in the marine world. From portable hand-held walkie-talkies to larger equipment capable of transmitting Digital Selective Calling (DSC), practically every vessel, no matter how large or small, uses a VHF radio set.

VHF stands for Very High Frequency. Marine VHF operates in the frequency range between 156 to 174 MHz. The most commonly used frequency is 156.8 MHz. This is the global distress frequency and is more widely known by its assigned channel number – 16. VHF radio uses line of sight communication. Thus, the higher the VHF antenna is placed, the greater will be the range of communication. The average range of a VHF broadcast is approximately 30 nautical miles. Under conditions of abnormal refraction this range may go up to as much as 60 nautical miles. Most of the present day VHF channels in use are simplex channels. This means that at one time you can either transmit or receive. There are also many duplex channels available, but their usage is not so predominant. Weather broadcasts are available on seven specified weather channels that range from 162.4 to 162.55 MHz.

Global Maritime Distress and Safety System. The Global Maritime Distress and Safety System (GMDSS) is an international system that uses terrestrial radio and satellite systems to alert concerned rescue authorities of any maritime distress. As a part of this system, all sea going vessels are required to carry certain types of communication equipment that conform to GMDSS requirements. While small recreational boaters do not have to comply with these requirements, in the interest of their own safety it is recommended that they do so.

If you are not required to comply with GMDSS regulations, at the very least you should consider investing in a small, inexpensive VHF radio set. This will enable you to rapidly contact shore-based authorities, or nearby vessels for assistance in case you are ever in distress. It must be borne in mind that VHF Channel 16 is only to be used in an emergency. Using Channel 16 for casual conversations may lead to severe fines. The Federal Communications Commission has also designated VHF Channel 9 as a supplementary calling channel for recreational water craft.

Digital Selective Calling. DSC is mandatory for all vessels that are required to comply with GMDSS regulations. VHF DSC is also highly recommended for vessels that are not required to comply with these regulations, as it greatly increases the chances of obtaining assistance in an emergency. DSC allows you to send a distress alert to nearby coastal stations and vessels with the press of a single button. The alert is sent in the form of a digital message that automatically relays an audible alarm to all stations in the vicinity. VHF DSC when interfaced with a GPS (Global Positioning System) can automatically relay your vessel’s updated position in the distress message. VHF DSC operates on Channel 70 and is monitored by all ships and coast stations that are a part of GMDSS. Most fixed VHF sets now come with a DSC option. Some of the most popular VHF DSC sets are manufactured by Icom, Furuno, Raytheon Marine, and Cobra. You can easily recognize a VHF DSC set by its prominent, red colored distress button.