Compagnie générale de la télégraphie sans fil
| File:A6.Émetteur de Sainte-Assise.crop.jpg | |
| Industry | Electronics |
|---|---|
| Founded | 1919 |
| Founder | Émile Girardeau |
| Defunct | 1968 |
| Fate | merged |
| Successor | Thomson-CSF |
| Headquarters | Paris , France |
The Compagnie générale de la télégraphie sans fil (CSF) was established in France in 1918 amid the restructuring and growth of the Société française radio-électrique (SFR), which became its subsidiary. CSF specialized in advancing technologies such as radio-telegraphy, broadcasting, radar, and television. The company offered telegraphy and broadcasting services and distributed equipment widely across the French colonial territories and international markets. In 1968, CSF combined with Thomson-Brandt, resulting in the creation of Thomson-CSF.
Background
During the late 1800s, long-distance communication depended heavily on telegraph cables and undersea wires. In 1887, Heinrich Hertz confirmed the existence of electromagnetic waves, while Alexander Stepanovich Popov developed antennas to enable wireless signal transmission. Pioneers including Édouard Branly and Nikola Tesla made significant contributions to radio technology. By 1895, Guglielmo Marconi had invented wireless telegraphy and launched the Wireless Telegraph & Signal Company in England in 1897; its American branch was established in 1899 and later became RCA.
In Germany, the company Telefunken was created in 1903 as a collaboration between Siemens and AEG.
In France, military engineer captain Gustave-Auguste Ferrié spearheaded wireless telegraphy efforts for defense purposes. He showcased radio’s tactical importance during the Mount Pelée eruption and by installing antennas atop the Eiffel Tower. In 1908, polytechnic engineer Émile Girardeau joined Ferrié’s team. Subsequently, Girardeau and scientist Joseph Bethenod established a French enterprise to fulfill both military and civilian radio communication demands.
Société Française Radio-Electrique (1910–19)
Founded on 3 April 1910, the Société Française Radio-Electrique (SFR) benefited from the significant involvement of Paul Brenot. Bethenod's innovations led to the first radiotelegraph connection in tropical regions between Brazzaville and Loango, which generated international contracts from Belgium, Mexico, Turkey, Bulgaria, Serbia, Italy, Russia, and China. From 1910 to 1914, SFR developed musical frequency resonance alternators, set up stations in Russian territories and the Belgian Congo, produced portable field transmitters deployed during the 1912–13 Balkan Wars, and equipped airships, airplanes, naval vessels, fishing boats, and passenger ships with transmitters.
The outbreak of World War I intensified research into radio technologies. Serbia and Romania placed orders for new stations. The French Navy constructed a principal facility at Basse-Lande (Brains, Loire-Atlantique) featuring arc and spark transmitters. SFR supplied 65 fixed stations exceeding 5 kW output power along with 18,000 aircraft stations, 300 maritime stations, and 300 mobile units for vehicles. Additionally, a continuous wave apparatus based on the Bethenod method was installed at the Lyon la Doua station.
Formation (1918–19)
The Compagnie générale de la télégraphie sans fil (CSF) was founded in 1918 following the achievements of SFR and an investment initiative spearheaded by the Banque de Paris et des Pays-Bas (BPPB) alongside the Compagnie Française des Câbles Télégraphiques (CFCT), which operated transatlantic telegraph networks. This arrangement also allowed BPPB to capitalize on rights connected to confiscated German properties. Émile Girardeau led CSF as a holding entity that included SFR, specializing in radio telegraphy, and subsidiaries responsible for managing radio telegram services, maritime radio communications, and broadcasting operations.
In 1919, SFR established a manufacturing facility in Levallois-Perret, located northwest of Paris. After leaving military service, Paul Brenot assumed the role of technical director at SFR.
While CSF maintained strong financial connections with BPPB, it functioned autonomously from its subsidiaries, effectively serving as their financial institution. The company’s income was primarily derived from royalties paid by its subsidiaries for patent usage; dividend returns were modest. Research activities were centralized within CSF’s main laboratory, which held all patents on behalf of the group.
Inter-war period (1919–39)
During this era, CSF attracted promising young physicists who had difficulty securing academic positions by offering competitive remuneration and well-equipped facilities. Among these recruits were Yves Rocard (1903–1992), who joined Radiotechnique in 1928 before contributing to France’s nuclear weapons program, and Maurice Ponte (1902–1983), who entered in 1929 and oversaw the SFR vacuum tube division as well as the general research laboratory, recruiting specialists in electronics and electromagnetic wave studies.
By 1925, CSF’s workforce numbered approximately 1,600 employees and expanded to nearly 4,900 by 1935, including personnel from Radiotechnique, then jointly owned with Philips. In compliance with government directives requiring strategic suppliers to establish operations south of the Loire River, SFR relocated to Cholet in Maine-et-Loire in 1935. The Cholet facility grew from a subcontracting site into a fully independent operation with complete administrative and technical departments, increasing its staff from 25 in 1937 to 1,250 by 1957 over an area of 22,000 m².
Throughout this timeframe, CSF participated in a cartel alongside German Telefunken, British Marconi, and American RCA companies. These firms coordinated through the International Broadcasting Union to share patents via cross-licensing agreements and divide markets strategically. CSF’s core markets encompassed France and its colonial territories, Serbia, Argentina, and Chile; it also maintained branches across the Middle East, China, Japan, and the Soviet Union.
Radio transmission services
To advance radio technology development, CSF received in 1920 the exclusive concession to construct and manage all international radio communication links originating from France. A major initiative was the Sainte-Assise long-wave transmission station near Melun operated through its subsidiary Radio-France. This facility featured eight towers each standing 250 meters tall supporting two antennas powered by four alternators rated at 500 kW each; it commenced operations in 1922. Although shortwave transmissions were generally favored for intercontinental communication due to ionospheric reflection properties, Sainte-Assise remained a critical asset for emergency communications. Radio-France began broadcasting to Europe, America, and the Far East starting in 1921 under a state concession lasting thirty years. Additionally, the Société Radio-Orient subsidiary provided comparable services throughout the Near East.
SFR’s Levallois-Perret site initiated experimental broadcasts in June 1922 and obtained authorization for scheduled programming on 31 October 1922; advertising was initially prohibited. The Radiola station launched early November 1922 as France’s first private radio broadcaster and was renamed Radio-Paris in 1924. Additional stations were established in locations including Clichy, Toulouse, Algiers, Ankara, Tunis, Rennes, Lille, and Strasbourg. In response to political pressures during 1933, Radiola was sold to the French government.
Radio equipment
CSF manufactured radio transmission and reception devices for both hobbyists and industry professionals. Its subsidiary, Radio Maritime, provided equipment specifically for merchant vessels. Radiotechnique, founded in 1919 in Suresnes, concentrated on the innovation of electronic tubes used in transmission and reception. The brand name "Radiola" was applied to both radio receivers and the associated broadcasting station.
Although France initially escaped the worst of the Great Depression, by 1929 CSF experienced repercussions due to the global downturn impacting radio transmission markets. That year marked the integration of CSF’s amateur radio equipment division into Radiotechnique, alongside a strategic partnership with Philips, which acquired a 50% stake in Radiotechnique, thereby gaining effective control. This arrangement resulted in CSF withdrawing from the amateur equipment sector while Philips agreed not to enter the professional market. The amateur receiver market expanded significantly in 1930, allowing CSF to utilize its investment in Radiotechnique to strengthen its position within professional segments. Consequently, production of professional electronic tubes was relocated from Suresnes to the SFR facility in Levallois.
In late 1937, Maurice Elie at SFR pioneered pulse-modulated transmitter tubes that enabled a new 16 cm system capable of delivering peak power close to 500W with a pulse duration of 6μs. Patents for this technology were filed in both France and the United States by December 1939.
Radar
After Radiotechnique became independent, Rocard and Ponte moved operations to Levallois. Ponte assumed leadership of the "lampes" (electronic tubes) division while continuing investigations into magnetrons for ultra-short wave generation, instrumental in early obstacle detection systems—precursors to radar technology primarily aimed at identifying ships and icebergs rather than aircraft. During the 1920s, physicists Camille Gutton and Émile Pierret conducted experiments using 16 cm wavelengths. In 1934, a CSF team led by Maurice Ponte and Henri Gutton secured a patent for a radar detection system following studies on cavity magnetron devices operating at 16 cm and 80 cm wavelengths. Between 1934 and 1935, CSF equipped the SS Oregon and SS Normandie with anti-iceberg collision detection systems capable of approximately 10 km range.
Film and television
Responding to requests from the PTT, CSF established Radio-cinéma in 1929 to develop sound film projectors tailored for large cinema venues during the emergence of talking pictures. Initially located in Paris’s 20th arrondissement, Radio-cinéma designed and produced projectors for major theaters. While CSF did not manufacture television cameras or receivers, starting in 1935 it became the primary partner of the PTT for television transmitter development.
World War II (1939–45)
By 1939, CSF employed just over 4,000 workers—a smaller workforce compared to competitors such as Telefunken, Marconi, RCA, and Philips. Early in World War II, research laboratories at Levallois advanced the cavity magnetron, a key technology underpinning centimeter-wave radar extensively utilized by Allied bombers and night fighters from 1943 onward. On May 8, 1940, Maurice Ponte personally delivered the CSF-developed magnetron to British representatives who incorporated it into their own radar prototypes.
During German occupation, control of Levallois and Cholet plants was transferred to Telefunken. The SIF facility in Malakoff operated under Siemens & Halske supervision, while Radiotechnique at Suresnes came under Philips Electro Special—a German branch of Philips. Paul Brenot held the role of technical director at SFR and acted as deputy to Émile Girardeau. Although Brenot faced criticism for his close association with Telefunken during occupation, he defended his relationship with their representative Dr. Schultz, who was known as a liberal anti-Nazi former musician.
SFR created a research center in Lyon within the unoccupied zone and arranged transfers for Jewish employees there. A small manufacturing site was also established in Algiers. Operating under German oversight as a Telefunken production hub, SFR’s output primarily served the German military—accounting for 65% of revenue between 1940 and 1944 and peaking at 86% in 1943. Workforce levels varied from around 2,600 employees in February 1940 down to approximately 1,000 by August but increased again beyond 4,000 by 1943. The majority of products were based on Telefunken designs. Several capital infusions during this period were facilitated by BPPB.
Pierre Grivet, an École Normale Supérieure alumnus appointed to Levallois-Perret’s research laboratory during wartime, contributed to developing a high-voltage (60kV) oscilloscope essential for television research efforts. Additionally, he secured government contracts for an electrostatic electron microscope despite limitations imposed by occupation conditions.
Post-war era (1945–68)
During the early 1950s, microwave research at CSF’s Paris site was directed by Robert R. Warnecke.
Following World War II, Radio-cinéma shifted its operations to Courbevoie, situated close to other factories in Levallois. In 1947, it introduced the Spectro-Lecteur, a spectrum analysis instrument developed to meet the requirements of metallurgical company Pechiney. The early 1950s saw the acquisition of André Charlin’s firm, which strengthened the company’s capabilities in audio technologies such as loudspeakers and stereophonic sound. In 1954, Radio-Cinema changed its name to Compagnie des Applications Mécaniques et Electroniques au Cinéma et à l'Atomistique (CAMECA), expanding its focus into precision engineering for scientific instruments and aerospace radar systems. By 1955, CAMECA had established three main divisions: film projectors (including Radio-Cinema and Charlin), mechanical manufacturing serving CSF subsidiaries, and continued development of the Spectro-Lecteur device. Subsequently, the company made significant progress in ion and electron microprobe technology.
In 1957, CSF incorporated SFR into its operations. A decade later, in 1968, Thomson-Brandt merged with CSF to create Thomson-CSF—a leading industrial entity that was nationalized in 1982 and later privatized in 1997.