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The Maser
Published in Mario Bertolotti, The History of the Laser, 2004
One of the more interesting applications of atomic beam masers was found in the construction of atomic clocks. Very precise clocks can be used to establish if the astronomical ‘constants’ stay fixed or change with time and may allow the general relativity theory to be verified. Besides their scientific meaning, atomic clocks have important military and commercial uses. In the 1950s and 1960s precise frequency standards were required for earth-based stations and in planes using long-distance aerial radio-guided navigation system that at that time was in the final stage of development by the US Army Signal Corps. Highly stable frequency standards resistant to vibration were also part of the electronic equipment mounted on teleguided missiles, research which was financed by the military.
Wireless Networks
Published in Vikas Kumar Jha, Bishwajeet Pandey, Ciro Rodriguez Rodriguez, Network Evolution and Applications, 2023
Vikas Kumar Jha, Bishwajeet Pandey, Ciro Rodriguez Rodriguez
Marconi was able to transmit and receive a coded wireless signal message at a distance of 1.75 miles near his home in Bologna, Italy, in 1895. He presented his developed operational wireless telegraph apparatus to the British telegraph authorities in February 1896 and filed his first British patent in June 1896. He then successfully sent wireless signals over a distance of 1.75 miles on Salisbury Plain in July 1896 with the assistance of Mr W.H. Preece, chief electrical engineer of the British Post-office Telegraphs. Furthermore, a greater distance of 4 miles was covered on Salisbury Plain with wireless signals in March 1897. Wireless communication covering a distance of 8 miles was established between Lavernock Point and Brean Down in England on May 13, 1897. His next demonstration was of a radio transmission to a tugboat covering an 18-mile path over the English Channel in 1897. In this year, Wireless Telegraph and Signal Company was founded as the first wireless company which bought most of Marconi’s patents. The erection of the first Marconi station at Cape Cod, Massachusetts, started in 1900. Radio devices were installed by Marconi Company [9] at five stations on five islands of the Hawaiian group in March 1901. The Canadian government installed two stations in the Strait of Belle Isle this year. Also, the construction of the New York Herald stations at Nantucket, MA, and Nantucket light ship happened in 1901. The first international wireless message was sent by Marconi from Dover, England, to Wimereux, France, in 1899. Marconi further received the famous letter “S” at St Johns, Newfoundland, which was transmitted as a test signal from his English station on December 11, 1901. Several of the US government agencies, including the Navy, the Department of Agriculture, and the Army Signal Corps, started setting up their own radio transmitters in 1904. This was supported by a board with representatives from these agencies appointed by President Theodore Roosevelt to prepare recommendations for coordination of governmental development of radio services in 1904 [10].
Front-line Fowl: Messenger Pigeons as Communications Technology in the U.S. Army
Published in History and Technology, 2021
Alice Shackelford Clifton-Morekis
Officially established in 1860 and organized in 1863, the U.S. Army Signal Corps was primarily responsible for constructing, maintaining, and operating Army communications through various means as well as conducting research and development (R&D) to advance Army communications systems.84 Initially limited to flag-based field signals, the Corps gained responsibility for several more communications technologies as it discovered and designed military uses for them. Its first decades saw frequent reorganization, and the Corps occasionally acquired and lost duties like operating a national weather service.85 The organization arguably found a coherent purpose and a firm place in the Army structure only after it proved the value of electronic communications in the 1898 Spanish-American War.86 By the start of World War I, communications systems under the purview of Signal Corps included field signals by flag and light as well as telegraphy, telephony, and radio.87