Battles & Wars › Industrial wars › Electric telegraph and Morse code
Radio (wireless telegraphy)
1895 (Marconi); used in war at sea 1904–05· Invention or discovery· Technology, codes & intelligence
Well documentedSolid records, physical evidence or scientific consensus.
Sending Morse code through the air on radio waves, first shown by Guglielmo Marconi in 1895 and adopted first by navies.
See it on the Battles & Wars map →What happened
Heinrich Hertz proved radio waves existed in 1887. In 1895 the young Italian Guglielmo Marconi used them to send Morse code without wires, then moved to Britain and patented his system. His signals crossed the Atlantic in 1901. Navies bought first, since wires could not reach ships; both fleets used radio in the Russo-Japanese War. Vacuum tubes later carried voice. By 1939 tanks, planes and ships carried sets, and armies needed strong codes because anyone could listen.
Why it matters
For the first time commanders could talk in real time to forces out of sight. It enabled fast maneuver and air-ground teamwork, and created modern signals intelligence.
How we know
Marconi's patents and demonstration records, navy contracts from 1900, Japanese and Russian records of Tsushima, and wartime intercept files.
Still debated
Who invented radio is disputed: Marconi, Nikola Tesla, Oliver Lodge, Alexander Popov and Jagadish Chandra Bose all have claims. A 1943 US Supreme Court ruling voided some Marconi patents.
Connections (3)
▸Electric telegraph and Morse code went wireless as Radio (wireless telegraphy)Well documented
The connection
Wires carried Morse code across continents from the 1840s but could not reach ships at sea or fast-moving armies. Marconi's radio sent the same dots and dashes through the air on electromagnetic waves. Navies were the first big buyers; Britain's Royal Navy ordered Marconi sets in 1900, and soon fleets could be commanded beyond sight of land.
When and how
Bologna, Italy, 1895; Britain, 1896–97 (patent and demonstrations); first transatlantic signal, December 12, 1901; Royal Navy orders from 1900.
How we know
Marconi's patents and demonstration records, navy contracts, and the use of Morse code over radio by ships until the 1990s.
Debates and open questions
How much Marconi invented, rather than combining others' discoveries such as Hertz's waves and Édouard Branly's detector, is still argued.
▸Radio (wireless telegraphy) relayed the enemy sighting that opened the Battle of TsushimaWell documented
The connection
Admiral Tōgō waited with Japan's fleet at Jinhae Bay on Korea's south coast. Before dawn on May 27, 1905, the scout ship Shinano Maru sighted the Russian fleet in fog and radioed 'enemy sighted.' Tōgō sailed at once and met the Russians in the strait. Russian ships heard the signals but reportedly were refused permission to jam them.
When and how
Tsushima Strait, between Korea and Japan, May 27, 1905; Admiral Tōgō Heihachirō against Admiral Zinovy Rozhestvensky's Baltic Fleet.
How we know
Japan's official naval history, Tōgō's battle report and Russian survivors' accounts record the sighting and the signal.
Debates and open questions
Whether jamming could have changed the outcome is unknowable; Japanese gunnery and Tōgō's tactics probably decided the battle anyway.
▸Radio (wireless telegraphy) coordinated the tanks and planes of Blitzkrieg (combined-arms maneuver warfare)Well documented
The connection
Heinz Guderian, a signals officer in World War I, insisted that every German tank carry a radio and that commanders could talk to each other and to supporting aircraft. Panzer units could react in minutes instead of hours. In 1940 many French tanks had no radio, so their crews often relied on flags and runners.
When and how
Germany, 1930s; Poland, 1939; France, May–June 1940; Guderian and German signals troops.
How we know
Guderian's books, Achtung–Panzer! (1937) and Panzer Leader, German equipment tables, and French postwar inquiries into the 1940 defeat.
Debates and open questions
How much radio mattered next to surprise, French command errors and the Ardennes gamble is debated; 'blitzkrieg' itself was never formal German doctrine.