Maurice Ponte and Henri Gutton, pioneers of early French studies on resonant magnetron (1932–1940)

After a quick reminder of French scientists who pioneered the UHF domain in the 20\´s, emphasis is put on the decisive role of Maurice Ponte at SFR/CSF, who revived Okabe\´s magnetron concept in 1932 and built up a lot of high efficiency oscillating valves working within the range 3 m - 70 cm. Two years later H. Gutton succeeded him and began to work on multi-segment, resonating anode design. Between 1934 to 1938 he tested a large variety of anode architectures, resulting finally in the 8-segment anode and oxide-coated cathode M-16 which in late 1939 delivered a peak power record of 1 kW at λ = 16 cm. The M-16 found immediate applications in radio-link communications, particularly in a naval obstacle detector (a very early decimetric radar) tested on board the liner "Normandie" from mid-1935. It was improved in a dedicated laboratory established in 1936 at Le Havre. But its military adaptation had to be destroyed in June 1940 to escape the German invasion. The legacy of these works survived through the scientific exchanges established throughout this time between Dr. Ponte/Gutton at SFR and Dr. Megaw at GEC UK. They had a noticeable influence on the emergence of the British multi-cavity anode invention. In May 1940 the oxide-coated and indirectly heated cathode brought to Wembley by Ponte was the final touch. Promptly inserted in the new E-1189 GEC prototype, it proved to be an essential part of "the most valuable cargo" sent by the Tizard mission to the US a few months later.