VLF transmitter Grimeton

The VLF transmitter Grimeton is a VLF transmission facility near Grimeton close to Varberg in Sweden. It was built in 1923 and has the only workable machine transmitter in the world. For its radiating element it uses a wire aerial hung on six 127 metre high freestanding steel towers looking like giantic pylons. These towers are grounded.

The VLF transmitter Grimeton was used until the fifties for transatlantic radio telegraphy to Radio Central in Long Island, USA. After the fifties it was used until 1996 for transmitting orders to submarines. In 1968 therefore a second transmitter was installed. This transmitter is using transistor and tube technology and in opposite to 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 was obsolete and went out of services. Because it is in good shape it was declared to a national monument. On special occasions as Alexanderson Day it is used for transmitting Morse messages on 17.2kHz. The machine transmitter can be visited at summertime. It is especially on Alexanderson Day a great attraction.

The transmitter from the 60ies is still used by the Swedish Navy. Since it uses the same aerial as the machine transmitter a simultanous operation of both transmitters, which would require expensive frequency filters is not possible. So these special transmissions are very rare. The VLF transmitter Grimeton is not only used for VLF transmission. It is also used for shortwave transmissions and for FM- and TV-broadcasting. Therefore next to the building containing the transmitter for 40 kHz a 260 metre high guyed steel framework mast was built in 1966.

On July 2, 2004 the VLF transmitter Grimeton got World Cultural Heritage of UNESCO.

• List of masts
• List of towers