The 7777 Wireless Patent - 1900
Guglielmo Marconi (1874 - 1937)

This is an original of the famous "four-seven's" patent issued to Marconi's Wireless Telegraph Company on April 26, 1901. Prior to this time one of the major problems Marconi faced was interference between transmitting stations. The primary research undertaken at the time resulted in the creation of a transmitter and receiver system in which all four major components were tuned. This development was what gained Marconi the Patent "for improvements in apparatus for wireless telegraphy".

Marconi's solution was inspired by an experiment patented in 1897 by his old rival Professor Oliver Lodge, of tuning the sending and receiving aerials. Marconi's patent was for selective tuning in which other circuits in the transmitter and receiver, as well as the aerials were tuned to the same wavelength.⁹

Lodge was unhappy and litigation followed. But the new technique made possible Marconi's next great scheme, to span the Atlantic by wireless⁹.

The 1904 U.S. version of the 7777 patent,  US patent No. 763,772, was found to be invalid in a celebrated 1943 Supreme Court decision. There are some that claim this decision affirmed Nikolai Tesla as the inventor of radio. For the complete story on the controversial decision, visit Antenna,  at the following link: http://www.mercurians.org/nov98/misreading.html

 
Transmitter & Receiver
Schematic diagrams from Patent application