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:
Ceský Sternberk Castle is an early Gothic castle which was constructed, named and still owned by members of the same family. Today it is a residence that bears a long historical and architectural heritage and represents an attractive tourist destination open to the public. It is considered one of the best preserved Gothic Bohemian castles.
The castle was initially built in 1241 by Zdeslav of Divisov, later called Zdeslav Sternberg. The development of new firearms in the 14th century posed an unexpected threat to the defensibility of the castle. Its 13th century architects hadn't foreseen the danger of long-range firearms and its reinforcement became a necessity. During this period the Ceský Sternberk castle's fortifications were improved through the construction in the north of a three-story tower, which was connected to the castle by a rampart. In 1467 the castle was seized by the royal armies of George of Podébrady. Later, the ruined castle was regained by Sternberk's aristocracy, who, by the turn of the 15th to 16th century, had reconstructed the castle, renewed its defensive system and expanded it with the construction of a new cylindrical tower in the south and the Dungeon in the north. The castle managed to survive the looting of the rebels in 1627, during the Thirty Years' War. With the death of Jan Václav in 1712, the Holicý branch of the Sternberg family died out and its ownership passed to other families, who in 1751 built the lower palace next to the surrounding wall.
The ownership of the castle was returned to the Sternberg family in 1841 when Zdenék of Sternberg from the Konopisté branch of the family bought it. It remained in Sternberg's ownership until 1949 when it was nationalized by the Communist government of the Republic of Czechoslovakia. After the fall of Communism and the Velvet Revolution, in 1992, Ceský Sternberk castle returned to Jirí's son, the count Zdenék Sternberg, the current owner of the castle.
Ceský Sternberk Castle was originally built as a Gothic castle. Eventually it underwent several periods of reconstructions and further fortification and the Gothic architectural features were in parts concealed by the new reconstructions. Especially the interiors of the castle were realized under the Baroque and Rococo styles. In 1760, the master Carlo Brentano performed the elaborate stuccoing and renderings of the halls' interiors. The castle offers a rare collection of 545 copper engravings, depicting the entire history of the Thirty Years' War. Also, historical weapons and hunting trophies are exhibited within the castle's halls.