The VLF transmitter Grimeton was used until the fifties for transatlantic radio telegraphy to Radio Central in Long Island, New York, USA. After the fifties it was used until 1996 for transmitting orders to submarines. In 1968 therefore a second transmitter was installed. This transmitter uses transistor and tube technology unlike the machine transmitter, which works on 17.2 kHz, designed for frequencies around 40 kHz, but using the same aerial. In 1996 the machine transmitter became obsolete and went out of service.