| Year |
Inventor |
Description |
Patent No. |
| 1872 |
William H. Ward |
This patent hasn't any practical or scientific meaning. An electrical layer in the atmosphere that could carry signals like a telegraph wire between grounded towers that must be in constant contact with this layer that surrounds the earth (similar to Mahlon Loomis patent No. 129971). |
US126356 |
| 1886 |
Amos Emerson Dolbear |
This device relied on conduction in the ground. Phones were grounded by metal rods poked into the earth. Transmission range was half a mile. The Dolbear patent prevented the Marconi Company from operating in the United States primarily because it was similar to the 1896 model of Guglielmo Marconi. In the end, Marconi had to purchase Dolbear's patent. |
US350299 |
| 1886 |
Thomas Alva Edison |
An electromagnetic induction system Edison called "grasshopper telegraphy", which allowed telegraphic signals to jump the short distance between a running train and telegraph wires running parallel to the tracks. This system was successful technically but not economically, as there turned out to be little interest by train travelers in an on-board telegraph service. |
US465971 |
| 1890 |
Nikola Tesla |
An alternator that produced radio high-frequency current of around 10,000 hertz. Tesla suppressed the disagreeable sound of power-frequency harmonics produced by arc lamps operating on frequencies within the range of human hearing. The produced pulsations were in the longwave broadcasting range (LF) and very low frequency band (VLF). |
US447920 |
| 1891 |
Nikola Tesla |
A high-frequency coupled oscillator circuit with an air-cored transformer (early disruptive "Tesla" coil) which converts low-frequency currents into "current of very high frequency and very high potential", which then supplies single-terminal lamps. |
US454622 |
| 1896 |
Guglielmo Marconi |
This Marconi patent is the first description in print of a wireless telegraphy device. A primitive spark gap transmitter and receiving station with no tuning at all, would operate only over very short distances. The transmitter used a Ruhmkorff coil, Morse key, rotary spark gap; receivers used a coherer detector. It used various earlier techniques and instruments of various other experimenters, primarily Tesla and also Popov. Later claimed by Oliver Lodge to contain his own ideas which he failed to patent. Invalidated by the Court of Claims decision from 1935. (US586193; RE11913). |
GB12039 |
| 1897 |
Nikola Tesla |
An early Tesla coil, developed currents of high potential and was composed of a primary and secondary coil where the secondary being inside of, and surrounded by, the convolutions of the primary coil. The apparatus was also connected to ground when the coil was in use. |
US593138 |
| 1897 |
Nikola Tesla |
An early Tesla transmitter consisting of a flat-spiral quarter-wave resonator and an elevated terminal. It was upheld in the 1943 Supreme Court decision. |
US645576 |
| 1897 |
Nikola Tesla |
Fundamental means for transmitting and receiving radio waves and energy. Build from a signal generator, primary and secondary coils at the transmitting and receiving stations. |
US649621 |
| 1898 |
Oliver Joseph Lodge |
By the making of the antenna coil or inductance variable, Lodge introduced the important concept of tuning in order to select a desired station (the "syntonic" tuning concept). In 1912 Lodge sold the patent to Marconi, and it was upheld in the 1943 Supreme Court decision. |
US609154 |
| 1898 |
Nikola Tesla |
Wireless remote control of boats. Employed the first logic gate and rotating coherers, allowed secure communication between transmitter and receiver. |
US613809 |
| 1899 |
Julio Cervera Baviera |
Basic wireless system. Some see him as the true inventor of radio. |
GB20084 |
| 1900 |
Guglielmo Marconi |
A four-circuit design, which featured two tuned-circuits at both the transmitting and receiving antennas in order to prevent the restriction of the number of spark-gap radio transmitters which could operate simultaneously in a geographical area without causing mutually disruptive interference. Found to be invalid in the 1943 Supreme Court decision. (US patent No. 763,772). |
GB7777 |
| 1900 |
John Stone Stone |
An adjustable tuneable antenna circuit design (LC) for removing parasitic oscillations in the transmitter. Upheld in the 1943 Supreme Court decision against Marconi's patent 763772. |
US714756 |
| 1901 |
Guglielmo Marconi |
This system was more advanced than Marconi's previous works by enabling tuning capabilities by the inclusion in the aerial circuits, at both the transmission and receiving stations, variable induction coils. |
US676332 |
| 1901 |
Jagadis Chunder Bose |
Coherer detector and the earliest photovoltaic cell. The first patent awarded for a semiconductor device even if “semiconductor” wasn’t termed yet. Basically a pair of point contacts of galena connected in series with a voltage source. |
US755840 |
| 1902 |
Harry Shoemaker |
Wireless remote control of boats and other moving objects |
US711743 |
| 1902 |
Harry Shoemaker |
A wireless telegraph repeater which object is to make it possible to signal between stations more widely separated that before by inserting between such stations a repeating station which receives radiant energy from the transmitting station, and providing means for entirely insulating the wave responsive device at the repeating station before the transmitted energy is produced. |
US718535 |
| 1903 |
Joseph Murgas |
Telegraph tone system which diminished the time needed to deliver a signal - the use of two signals of different frequencies for the "dot" and the "comma" of the Morse code. |
US759826 |
| 1903 |
John Stone Stone |
Transmission of signals by electromagnetic waves from an elevated conductor (antenna). |
US767973 |
| 1903 |
Harry Shoemaker |
To reduce false signals received by employing a few distinct receiving devices working in parallel. |
US824676 |
| 1904 |
Christian Hulsmeyer |
Wireless remote control system that prevents disturbances from other electromagnetic resources. |
US810150 |
| 1905 |
John Ambrose Fleming |
Rectifying vacuum tube diode (GB24,805). |
US803684 |
| 1905 |
Archie Frederick Collins |
A system of wireless telephony using an electric arc light that enables high voltage and amperage without to damage the transmitter. |
US814942 |
| 1906 |
Greenleaf Whittier Pickard |
A silicon crystal point-contact radio detector - a fine pointed wire (cat's whisker) in delicate contact with the silicon crystal. |
US836531 |
| 1907 |
Lee De Forest |
Vacuum tube (valve) triode. |
US879532 |
| 1907 |
Nathan B. Stubblefield |
Means for electrically transmitting signals for securing telephonic communication between moving vehicles and way stations. |
US887357 |
| 1909 |
Ernst F. W. Alexanderson |
The Alexanderson mechanical alternator: a high-frequency generator, up to 100 kHz, for longwave transmissions, which made modulated (voice) radio broadcasts practical. |
US1008577 |
| 1913 |
Edwin H. Armstrong |
The regenerative circuit. |
US1113149 |
| 1913 |
Ernst F. W. Alexanderson |
Tunning and frequency selection by a push-pull configuration. |
US1173079 |
| 1919 |
Edwin H. Armstrong |
Superheterodyne receiver |
US1342885 |
| 1930 |
Edwin H. Armstrong |
Frequency Modulation (FM) receiver. |
US1941066 |
| 1955 |
Richard C. Koch |
Transistor Radio |
US2892931 |
