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Marine Radio

As its name suggests, a marine radio is a communication equipment specifically designed and standard for sea-going vessels. What makes it different is that it operates only in the VHF (very high frequency) range of radio signals which is between 156 and 174 megahertz (MHz). Hence, among sailors this two-way radio communications equipment is often referred to as a marine VHF radio. Its primary use is for emergency rescue communication or contacting ports, harbors or marinas.

International frequencies called channels have been reserved exclusively for marine VHF radio transmissions. The international calling and distress channel is Channel 16 which is set at 156.8 MHz. The power of this radio’s transmission ranges from a low of 1 watt to a high of 25 watts. Bigger and taller ships have the edge in transmission distance because of their high antennas which enable a maximum distance of up to 60 nautical miles or a little more than 110 kilometers. Smaller vessels with obviously their aerials almost at sea level could muster some 5 nautical miles or less than 10 kilometers in power range.

Communication via marine radio is mostly through simplex transmission, meaning that messages can only be transmitted in one direction at a time. Hence, the set itself is alternating as a transmitter and a receiver, with the options for either of the two functions chosen through the push of a button on the set or on its microphone.

Marine radio sets have fixed and portable models. The fixed set benefits from a more reliable power supply, more powerful transmission, higher and more effective antenna and larger control panels. Portable sets, on the other hand, are handy companions in an emergency, the very situation that the marine VHF was built for.