The Anthorn VLF transmitter is a very low frequency (VLF) transmitter near Anthorn, Cumbria, used primarily for transmitting orders to submarines on 19.6 kHz. Its callsign is GBZ.
The transmitter is a NATO facility, controlled from Northwood Headquarters along with three other VLF transmitters in Norway, Germany, and Italy.
The characteristic triangular pattern of roads clearly visible on the aerial photograph indicates that this was a World War II military airfield, in this case operated by the Royal Navy Air Service as HMS Nuthatch. The transmitter is now operated by VT Communications.