1897 – The Italian Guglielmo Marconi was the first to bridge large distances with electromagnetic waves. Today he is regarded as a pioneer of wireless communication.

Guglielmo Marconi

Guglielmo Marconi (1874–1937) was an Italian radio pioneer. Marconi was interested in the research of Maxwell and Hertz on the propagation of electromagnetic waves. In 1895 he developed a grounded transmitter antenna that could send signals to a point 2,400 meters away. In his experiments he used a wire tied to a wooden tent pole.

Fun Fact: The word for antenna is derived from the Italian name for tent pole, l’antenna centrale.

Marconi traveled to England in 1896. There he convinced the director general of the postal administration, William Preece, of the benefits of his system of wireless telegraphy and had the process patented. In 1899 he succeeded in establishing the first wireless connection across the English Channel, and in 1901 the first transatlantic radio transmission.

Marconi shared the 1909 Nobel Prize in Physics with German physicist Karl Ferdinand Braun for his work on wireless communications. In 1935 he received a professorship for the chair of radio waves at the University of Rome.

1900 Nicola Tesla suggested that the reflection of electromagnetic waves can be used to detect moving objects.

Nikola Tesla

1904 – The German engineer Christian Hülsmeyer invented the telemobiloscope, a device for monitoring traffic on the water. It measures the angles of electromagnetic waves sent to and from a metal object (in this case a ship) and allows the distance to be calculated. This is the first practical radar experiment documented.

Christian Hülsmeyer

Christian Hülsmeyer (1881–1957) is a German inventor and is considered the discoverer of the radar principle. Hülsmeyer studied the basics of electricity in Bremen. After completing his studies, he found a job at Siemens-Schuckert. He worked there for about two years and was in charge of the electrical equipment for ships. After the death of a friend who died in a ship collision, he left this company to set up a company in Düsseldorf that dealt with the construction of an apparatus for detecting maritime obstacles with the help of radio waves.

In 1904 he received a patent for a device, which he called the telemobiloscope. It used a spark gap as a transmitter that emitted a directional radio wave through a multipolar antenna. Upon hitting a metallic obstacle such as a ship, this wave was partially re-radiated to the transmitter site, where two receiving dipole antennas were used to operate an electric bell. This system could determine the approximate bearing angle of ships up to 3 km away but was not yet able to measure a distance.

Hülsmeyer successfully demonstrated the system in Germany and the Netherlands. However, neither the representatives of the German Navy nor any shipping companies were impressed. One of the problems was the possibility of multiple reflections in the case of intensive sea traffic. In addition, the device was quite difficult to operate and the bell was difficult to hear due to the noise of a ship’s engine. Hülsmeyer went back to work and on January 16, 1906, he received a second patent in America for an improved version, which allowed interference echoes to be filtered out. The lack of interest in these improvements eventually caused the collapse of this technique.