FM broadcasting
VHF Radio waves do not travel far beyond the visual horizon, so reception distances for FM stations are usually limited to 30–40 miles (50–65 km) They can also be blocked by hills or buildings.
Felixstowe
Radio Caroline ship MV "Caroline" was outside the three-mile limit at Easter 1964. It was the very first UK radio station aboard a ship in the North Sea, and intended to break the monopoly of the BBC. Radio Caroline had about seven million listeners in its first week on air. The station's slogan was "Your all-day music station", and it initially broadcast from 6am to 6pm, seven days a week. The transmitter had a power of 10 kW on 199 metres – 1.520 kHz. The ship moved to waters off the Isle Of Man in summer 1965 to become Radio Caroline North, while MV "Mi-Amigo" of Radio Atlanta on 201 metres became Radio Caroline South, broadcasting on first 199 later on 259 metres – 1.178 kHz with 50 kW of power on medium wave. Later the ship moved to waters off Clacton-On-Sea, Essex.