An antenna (also called aerial) is a device enabling the transmission and reception of waves which frequencies may vary. In addition, their size enables to receive or transmit waves at more or less long distances. These antennas are essential and are of various types: parabolic antennas (mainly used for satellite TV), broadband antennas, elementary antennas, and so on.

Thomas Edison was the first to register a patent for his discoveries which improved the transmission of electric signals. But it is Heinrich Rudolf Hertz, German engineer and physicist, who proved in 1888 by using two antennas the existence of electromagnetic waves. After his discovery and as he was teaching a a technical school, he gave a talk about this theory. One of his students then asked him if it would be of any use in the future. Hertz, as he did not anticipated that they would be used for anything but theoretic learning said no.

Antennas therefore enable for more than a century to listen a watch television and radio broadcastings and are more and more powerful! Warsaw radio mast, which was built in 1973, was the highest human construction of all times until it collapsed in 1991. It reached almost 650 meters height. Radio broadcastings could be listened to from North Africa and even North America! It seems that its collapse is due to maintenance problems, even though some rumors about a Soviet scheme was also put forward.