Harbor Radio

The harbor master hails you on the radio, wondering where in the hell you think you are going, when all of a sudden the sound of someone else chimes in, distracting the coastal dispatch and giving you time to turn around, hopefully avoiding the curious inspection of the authorities. Perhaps another day will afford you the opportunity to land undisturbed and unload your top secret cargo. Marine VHF radio is installed on all large ships and most seagoing small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas, and operates in the VHF frequency range, between 156 to 174 MHz. Modern day marine VHF radios not only offer basic transmit and receive capabilities, many package the ability to alert other boats, ships, shore stations with a single button press, and the ability to connect to a remote microphone and act as an intership intercom system. Still others have a built-in hailer that when connected to an external hailer horn can act as a public address system and/or output required fog signals when conditions warrant. The most sophisticated marine VHF radios have an alphanumeric keypad for data entry, are able to connect to optional voice scramblers, and a few even have the ability to use a Bluetooth headset. Sets can be fixed or portable. A fixed set generally has the advantages of a more reliable power source, higher transmit power, a larger and more effective aerial and a bigger display and buttons. A portable set (often essentially a waterproof, VHF walkie-talkie in design) can be carried on a kayak, or to a lifeboat in an emergency, has its own power source and is water-proof.