The VHF ship radio is the most common type in maritime radiocommunications, be it ship-to-ship or ship-to-shore. It operates on frequencies between 30MHz and 300MHz.
A VHF ship radio is installed on the vessel's bridge; it is used for ship-to-ship or ship-to-shore communication.
VHF radio communications are carried by electromagnetic waves. This line-of-sight propagation limits range to the horizon. Thus, there is a direct relation between antenna height and range. However, certain weather conditions allow the waves to bounce off an atmospheric layer, extending the signal's range. The VHF spectrum includes preassigned frequencies, called channels. For example, channels 6, 13, 16 and 70 are used for specific types of calls.
Ships subject to SOLAS regulations (passenger vessels in international waters and ships over 300 gt) in zone A1 must carry a VHF radio capable of digital selective calling (DSC). In addition, ships subject to GMDSS protocols must carry approved handheld VHF radios.
