Who: It's complicated... Nikola Tesla and Guglielmo Marconi both have viable claims to be considered the "father of radio" and it's unlikely either of them could have made their breakthroughs without the work of the other. The US Patent Office couldn't even decide, awarding and stripping patents off both of them during the peak of their bitter scientific rivalry.
When: The existence of radio waves was first discovered in 1873, and by 1901 long-distance radio communication was possible. The 1920s saw the radio become a popular household appliance in the US.
The radio story: The theory of electromagnetism, which found that sound among other things could travel long distances instantly via electromagnetic waves, formed the basis for the invention of radio in the late 19th century. Italian Guglielmo Marconi used a spark-generator based on Heinrich Hertz's original design to send the first radio signal across a room in 1894, before transmitting a message across the English Channel in 1899. But Marconi's technology incorporated a device invented by Nikola Tesla, who then went to the US Patent Office to secure the sole right of the "Tesla Coil", putting Marconi on the back foot.
Marconi, with the backing of his wealthy family and connections, formed a business to continue pursuing his dream and sent the first radio transmission across the Atlantic in 1901. Surprisingly, perhaps due to Marconi's popularity and power, the US Patent Office stripped Tesla of his patents and awarded Marconi with the rights to the invention of radio. Radio became popular in the early 20th century for entertainment, the mass spreading of information, and international relations. In 1943, Marconi sued the US Government for patent infringement during World War I but the Supreme Court avoided the lawsuit by simply reverting the original patents back to Tesla who had died a few months earlier.
Impact and legacy: The radio was the first technological form of entertainment to be available to the masses. Families in the 1920s would socialise by sitting in front of the fire place and listening to the opera. Advertising on the radio waves was introduced not too long after, and governments began to communicate with their citizens directly. Communication between countries became infinitely easier and, in times of war, allowed commanders to give orders miles away from the battlefield. The radio is not obsolete despite massive technological advances in the past century, highlighting its place as one of the most important innovations of all time.
Are you on the same wavelength as inventors of years gone by? Let your innovation be heard by entering the 2013 New Zealand Innovation Awards here and get the opportunity to take it to the world.