The Grimeton VLF transmitter in Vargerg is a VLF transmission facility, which has the only workable machine transmitter in the world. It has been declared a UNESCO World Heritage Site. The transmitter was built in 1922 to 1924; to operate at 17.2 kHz, although it is designed for frequencies around 40 kHz. The radiating element is a wire aerial hung on six 127-metre high freestanding steel pylons, that are grounded.
The Grimeton VLF transmitter location is also used for shortwave transmissions, FM and TV broadcasting. For this purpose, a 260 metre high guyed steel framework mast was built in 1966 next to the building containing the 40 kHz transmitter.
In 1945 the Grimeton VLF transmitter's twin station Nadawcza Radiostacja Transatlantycka Babice in Babice, Poland was destroyed. Until the 1950s, the Grimeton VLF transmitter was used for transatlantic radio telegraphy to Radio Central in Long Island, New York, USA. From the 1960s until 1996 it transmitted orders to submarines in the Swedish Navy.
In 1968 a second transmitter was installed which uses the same aerial as the machine transmitter but with transistor and tube technology. The machine transmitter become obsolete in 1996 and went out of service. However, because it was still in good condition it was declared a national monument and can be visited during the summer.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.