Lucien Rouzet - History of The Rouzet TSF (wireless Telegraph System)

History of The Rouzet TSF (wireless Telegraph System)

In the early years of the 20th century, radio connections, which used Morse Code, were only land transmissions. The techniques to amplify signals upon reception were still unknown, so the maximum distance at which messages could be detected depended entirely upon the transmitter's power.

In the military field, General Ferrié had a major communication network built, but the transmitting stations were too heavy to be carried aboard aeroplanes. Therefore, engineers tried to minimise the weight-to-power ratio, and short-distance connections between planes and the ground became possible.

Among those engineers was Rouzet, who developed a system that proved to be extremely efficient, as revealed during a test flight lasting nearly one hour at an altitude of more than 1,000 metres (3,300 ft) on 7 May 1912. Journalists were present, and articles reported the test and its results in French and foreign newspapers.

Rouzet then filed for patents in France and many other countries (with, not surprisingly, much difficulty in Germany, who was France's enemy at the time). The Société Industrielle de TSF et d'électricité (Industrial Society of Wireless Telegraph and Electricity) was set up to operate the invention, and devices were supplied to several countries (except Germany).

The French army, however, demanded an official comparative test with the other systems. In May 1914, on a single circuit over Blois and the Sarthe region, the test was carried out, with reception at Villacoublay. The signals broadcasted by the aeroplane carrying the Rouzet system were the only ones received unbroken. The military demanded another test, but war was on its way, and the test was not carried out. As a result, the French air squadrons had no wireless telegraph.

However, the Rouzet system was used by the allied forces. The British Admiralty mandated its use; a letter signed by Post Captain Navy Attaché to the Embassy of England on 23 January 1915 reads:

I am authorised by the Admiralty to inform you that the satisfactory results achieved so far can be attributed for a large part to the devices manufactured by your Establishment.

Later, the French Navy made widespread use of those devices for active observation of maritime aviation ranging more than 250 kilometres (160 mi) away. On land, Rouzet, from the top of the Eiffel Tower, was able to set up communications to even greater distances.

When the "lamp" for the amplification of signals on reception was perfected, interest was lost in Rouzet's system, and the operating company ceased activity. On that occasion, Rouzet was offered a silver cup, engraved in French with the salutation: "Tribute from the Board of Directors of the TSF and Electricity Industrial Company to their engineer, Lucien Rouzet, inventor of the first wireless telegraph system for aeroplanes."