Marconi magnetic radio wave detector, 1902.
© Science Museum / Science & Society Picture Library
Patented by Guglielmo Marconi (1874-1937), this detector was developed partly from one of his earlier patents and partly on the work of Harry Shoemaker. The action of all magnetic detectors is based on the work of Ernest Rutherford in 1896. Magnetic detectors of this type were very widely used between 1903 and 1912, particularly on ships. They were more sensitive than coherers but les so than a good crystal detector. However, magnetic detectors were preferred to crystal ones because of their greater reliability.