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 !valign=top| Henry 
 |valign=top| Henry detected inductive magnetic effects at a distance of two hundred feet. 
 |valign=top| He was focused on wired telegraphy and researched self-inductance.Eugenii Katz, ""Joseph Henry"". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics. 
 |valign=top| 1829Ames, J. S., Henry, J., & Faraday, M. (1900). The discovery of induced electric currents. New York: American book (cf., [...] experiment was performed in August 1829.) 
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 !valign=top| Hughes 
 |valign=top| In 1879, Hughes began research into radio waves. He noticed electrical interference in an induction balance he was working with. The observed effect was due to radio waves and he discovered and improved the coherer.Darrel T. Emerson, The Stage Is Set: Developments before 1900 Leading to Practical Wireless Communication 
 |valign=top| His discovery was taken no further after Hertz described it rigorously. 
 |valign=top| 1879Eugenii Katz, ""David Edward Hughes"". Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity, Biosensors & Bioelectronics. 
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 !valign=top| Maxwell 
 |valign=top| By 1864 Maxwell had become the first person to demonstrate theoretically the existence of radio (electromagnetic) waves, which are used by all radio equipment.""Electromagnetism, Maxwell’s Equations, and Microwaves"". IEEE Virtual Museum (2011). Retrieved on 2011-06-21.James Clerk Maxwell, A Dynamical Theory of the Electromagnetic Field, Philosophical Transactions of the Royal Society of London 155, 459-512 (1865). 
 |valign=top| Maxwell did not generate or receive radio waves.Estabrooks, M. (1995). Electronic technology, corporate strategy, and world transformation. Westport, Conn: Quorum Books. Page 27. (cf., [...] Maxwell did not prove that these waves actually existed [...]) 
 |valign=top| None (n/a) 
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 ===Discovery of spark-gap radio table=== 

 ===Early radio development table=== 

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 !valign=top|Branly 
 |valign=top| Researched coherers. In 1890 Branly showed that such a tube would respond to sparks produced at a distance from it.Branley, Comtes Rendues, 1890, page 785, and 1891, page 90. 
 |valign=top|Others would expound upon the idea of using such a tube.In 1592, at the meeting of the British Association at Edinburgh, George Forbes suggested that such a tube would respond to Hertzian waves. (Guthe ""Coherer action"" Transactions of the International Electrical Congress, St. Louis, 1904, page 242.) (Munck. Poggendorff Ann 1838, Vol. 43, p. 193.)In 1893 Professor Minchen demonstrated experimentally that such powders would respond to electromagnetic waves generated at a distance. He used a battery and galvanometer shunted around the powder to detect the effect of the waves. (Minchen, Proceedings Physical Society, London 1893, page 455.) 
 |valign=top| 1890 
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 !valign=top| Bose 
 |valign=top| Researched coherers.Fleming, J. A. (1908). The principles of electric wave telegraphy. London: New York and. (