Artículo Usado
Estado : Muy Bueno
Disponibilidad : 1
Género : Química
Idioma : Castellano
* tapa dura, solapa deteriorada
318 páginas
Traducción Meyer Marcos Glikin
1946
Medidas :
16.5x23.5 cms.
Archie Frederick Collins (January 8, 1869 – January 3, 1952), who generally went by A. Frederick Collins, was a prominent early American experimenter in wireless telephony and prolific author of books and articles covering a wide range of scientific and technical subjects.[1][2] His reputation was tarnished in 1913 when he was convicted of mail fraud related to stock promotion. However, after serving a year in prison, he returned to writing, including, beginning in 1922, The Radio Amateur's Handbook, which continued to be updated and published until the mid-1980s.
Collins was born in South Bend, Indiana to Captain Thomas Jefferson and Margaret Ann (Roller) Collins. He attended public schools and graduated from the Old University of Chicago, a Baptist school which preceded the present University of Chicago.[3] His brother was author Dr. Thomas Byard Collins.[4] After graduating, he began working for the Thomson-Houston Electric Company in Chicago in 1888.[5] He married Evelyn Bandy on June 28, 1897, and they had a son, Virgil Dewey Collins, who also became an author, sharing writing credits on some of his father's books. Collins resided at a summer home called "The Antlers" in Rockland County, New York in the hamlet of Congers, and had a second residence in Florida.[1] His winter residence was New York City, and he died in Nyack, New York.An unusual example were his experiments in using brain tissue to detect radio waves.[6][7][8] The first radio receivers prior to 1904 used a primitive device called a coherer to detect the radio waves. The poor performance of the coherer led to much research to find a better radio wave detector. Collins was intrigued by reports of people "predicting weather" by aches and pains in their body, and examples of lightning strikes, which were strong sources of radio waves, causing convulsions in nearby people who were not actually struck. Since the brain was known to operate electrically, Collins thought it might be sensitive to radio waves. He applied DC current from a battery to two electrodes in dissected animal brains, causing a small current through the tissue, as in a coherer. Then he radiated the brain with pulses of radio waves from a Hertzian spark radio transmitter, and listened with earphones to the circuit. If the radio waves caused changes in the conductivity of the neural tissue, it would cause transient changes in the current, which would be audible as "clicks" in the earphones. His research culminated in experiments on a fresh human brain from a cadaver. Collins claimed that the brain had a 'cohering' effect, its conductivity changed when irradiated. However other researchers were unable to reproduce the effect.
The "spark" radio transmitters during Collins time could not transmit sound (audio) as modern AM and FM radio transmitters do. This was because the discharge of a spark cannot produce continuous waves, but only damped waves. Instead they transmitted information by telegraphy, the operator turned the transmitter off and on by tapping on a switch called a telegraph key to produce different length pulses of damped radio waves, to spell out text messages in Morse code. By the last years of the century, many wireless researchers such as Reginald Fessenden, Ernst Ruhmer, William Dubilier, Quirino Majorana, and Valdemar Poulsen were working to develop continuous wave transmitters which could be modulated to carry sound, radiotelephony.
The "spark" radio transmitters during Collins time could not transmit sound (audio) as modern AM and FM radio transmitters do. This was because the discharge of a spark cannot produce continuous waves, but only damped waves. Instead they transmitted information by telegraphy, the operator turned the transmitter off and on by tapping on a switch called a telegraph key to produce different length pulses of damped radio waves, to spell out text messages in Morse code. By the last years of the century, many wireless researchers such as Reginald Fessenden, Ernst Ruhmer, William Dubilier, Quirino Majorana, and Valdemar Poulsen were working to develop continuous wave transmitters which could be modulated to carry sound, radiotelephony.
Collins began researching the topic on his own in 1898. In November 1899, the American Wireless Telephone and Telegraph Company, headquartered in Philadelphia, Pennsylvania, was founded by stock promoter Dr. Gustav P. Gehring as the first American radio communications firm. Initially Collins acted as that company's primary technical advisor, however, he soon had a falling-out and left the firm, even demanding that his photograph in a company prospectus be altered to make him unrecognizable.
Collins returned to doing his own research, investigating, in turn, wireless telephone systems that employed conduction, induction, and finally radio waves. He established a small laboratory at No. 132 South Sixth street in Philadelphia, forming a developmental company that initially was privately financed and did not sell stock to the public.[11] After doing initial tests within a bowl of water,[12] he reported that he then made steady, although somewhat limited, progress with the conduction and induction approaches, achieving transmission distances of 60 meters (200 feet) in 1899, 1.5 kilometers (1 mile) across the Delaware River in 1900, and 5 kilometers (3 miles) in 1902. That same year he constructed two experimental stations at Rockland Lake, New York, separated by 1.5 kilometers (1 mile), that successfully established two-way communication. In 1903, he made short-distance tests in the Hudson River in New York City, aboard the ferryboats John G. McCullough and Ridgewood,[13] and in July of that year predicted that "in a comparatively short space of time I am confident I shall telephone across the ocean".
Collins' conduction and induction wireless telephone apparatus was similar to that employed by Alexander Graham Bell, Amos Dolbear and Nathan Stubblefield. Bell's work never went beyond the demonstration stage, and Dolbear's patent, controlled by the American Wireless Telephone and Telegraph Company, was ruled by the U.S. courts be largely impractical. In 1902 Stubblefield sold the rights to his system to the newly formed Wireless Telephone Company of America, and by August that company's advertisements stated that "Nathan Stubblefield and Prof. A. Frederick Collins are now working together for the sole benefit of that company",[14] and there were plans to "license subsidiary companies in each state of the Union".[15] However, Stubblefield had actually withdrawn from the firm in June, due to his concerns that it was primarily a fraudulent stock promotion scheme.
Collins returned to doing his own research, investigating, in turn, wireless telephone systems that employed conduction, induction, and finally radio waves. He established a small laboratory at No. 132 South Sixth street in Philadelphia, forming a developmental company that initially was privately financed and did not sell stock to the public.[11] After doing initial tests within a bowl of water,[12] he reported that he then made steady, although somewhat limited, progress with the conduction and induction approaches, achieving transmission distances of 60 meters (200 feet) in 1899, 1.5 kilometers (1 mile) across the Delaware River in 1900, and 5 kilometers (3 miles) in 1902. That same year he constructed two experimental stations at Rockland Lake, New York, separated by 1.5 kilometers (1 mile), that successfully established two-way communication. In 1903, he made short-distance tests in the Hudson River in New York City, aboard the ferryboats John G. McCullough and Ridgewood,[13] and in July of that year predicted that "in a comparatively short space of time I am confident I shall telephone across the ocean".
Collins' conduction and induction wireless telephone apparatus was similar to that employed by Alexander Graham Bell, Amos Dolbear and Nathan Stubblefield. Bell's work never went beyond the demonstration stage, and Dolbear's patent, controlled by the American Wireless Telephone and Telegraph Company, was ruled by the U.S. courts be largely impractical. In 1902 Stubblefield sold the rights to his system to the newly formed Wireless Telephone Company of America, and by August that company's advertisements stated that "Nathan Stubblefield and Prof. A. Frederick Collins are now working together for the sole benefit of that company",[14] and there were plans to "license subsidiary companies in each state of the Union".[15] However, Stubblefield had actually withdrawn from the firm in June, due to his concerns that it was primarily a fraudulent stock promotion scheme.