The Sender Inselsberg (transmitter Inselsberg) is a FM and television-transmission facility on the Big Inselsberg in Thuringia, Germany. It has two aerial towers, which were built in 1939 and 1974.
The transmission tower built in 1939 is a 43.31 metre high free-standing cylindrical tower built of steel concrete, which carried until the beginning of the nineties similar to Gerbrandy Tower a guyed steel tube mast on its top. This mast carried the FM- and TV-broadcasting aerials.
Nowadays this mast is demounted and there are only small aerials for mobile phone services on its top. The tower is nicknamed because of its cylindrical form "thermos flask".