(RARE SIGNED FIRST EDITION dust jacket hardcover, clean te...)
RARE SIGNED FIRST EDITION dust jacket hardcover, clean text, no remainders, NOT ex-library; some fading on jacket back (see image); WE SHIP FAST. 201210412 SIGNED by copyright holder "Patricia Ann Jensen Schindler" Jensen was one of the major innovators and inventors of modern electronic sound gear. We recommend Priority Mail where/when available -- $3.99 Standard / Media Mail can take up to 15 business days.
Peter Laurits Jensen was a Danish American engineer, inventor and entrepreneur. He founded Magnavox Company and Jensen Radio Manufacturing Company.
Background
Jensen was born on May 16, 1886, in Falster, Denmark, the son of Lods Ole Jensen and Hansine Petersen. His father was a navigator who piloted vessels through the waters between Falster and Lolland, and it was expected that Peter would follow family tradition by becoming a sailor. But a teacher noted his outstanding potential and urged that he receive an education that could lead to a university degree.
Education
After preliminary schooling in Moseby, Jensen went to a secondary school in Norre Alslev and at age sixteen passed the entrance examination for the University of Copenhagen. A university education was prevented by his father's death in 1901, which compelled him to help support his family by working for a lumber firm.
Career
Jensen's employer convinced him and his mother that he should seek larger opportunities befitting his talents. Lemvig Fog, a Danish engineer-entrepreneur, also took an interest in the lad, and in 1903 Jensen went to Copenhagen to become an apprentice in the laboratory of radio pioneer Valdemar Poulsen. Poulsen had just developed an improved transmitter for generating continuous radio waves by means of an arc that burned in an atmosphere of hydrogen in a strong transverse magnetic field. It was a temperamental device, and Jensen gained Poulsen's confidence by becoming adept at regulating it. Advancing to the rank of assistant, he became involved in Poulsen's efforts to broadcast the human voice rather than telegraphic impulses.
In 1906 Jensen made an important breakthrough by linking a microphone and a transmitter circuit as a sending apparatus and connecting a crystal detector to a grounded telegraph ticker as a receiver. While Poulsen's engineers developed the new method, Jensen experimented with various applications, including broadcasting recorded music to ships at sea. In 1909 Poulsen sold his American patent rights to a California enterprise, the Poulsen Wireless Telephone and Telegraph Company, which subsequently reorganized as the Federal Telegraph Company and became an important pioneer in American radio. With a fellow mechanic, Carl Albertus, Jensen went to California to install the Poulsen equipment. There he met Edwin Pridham, an electrical engineering graduate of Stanford University who taught him English and became his close friend and collaborator. The reorganization that produced Federal Telegraph left Jensen and Pridham jobless. After an unsuccessful attempt to secure patent rights from Poulsen, they obtained financial backing from California industrialist Richard O'Connor, and established their own research firm, the Commercial Wireless and Development Company. During the next few years, in a small bungalow on the outskirts of Napa, California, they developed the first dynamic horn loudspeaker, which they named the Magnavox ("Great Voice"). It utilized a coil of copper wire situated in an electromagnetic field and attached to the diaphragm of a sound reproducer. A vast improvement over previous speakers, the new device was first demonstrated in public at a football game in San Francisco in 1915. Subsequent demonstrations before a large crowd at the San Francisco Civic Center on Christmas Eve, 1915, and at the dedication of a new municipal auditorium shortly thereafter were so successful that additional capital was obtained from Frank M. Steers of the Sonora Phonograph Company of California. This led to the establishment of the Magnavox Company by 1917. Steers and O'Connor were executives in the firm, and Jensen and Pridham were its chief engineers.
During World War I, Jensen and Pridham developed an "antinoise microphone" that made the human voice audible over the roar of an airplane engine. Adopted by the U. S. Navy for use in the Curtiss NC-4 flying boat, it enabled crew members to communicate with one another during the navy's pioneering transatlantic flight from Newfoundland to Lisbon in May 1919. Magnavox also won national acclaim for a public address system for destroyers and battleships that Jensen and Pridham invented. But the company achieved its greatest recognition on September 19, 1919, when President Woodrow Wilson addressed a crowd of approximately 50, 000 people at San Diego Stadium from a glass-enclosed platform built to protect him from the elements. Speaking in a normal tone of voice, Wilson was heard distinctly by the throng with the aid of two Magnavox loudspeakers.
In the 1920's Magnavox continued to build public address systems. It also moved into the production of phonographs and home radio sets. Meanwhile, Jensen, now famous, visited Denmark and demonstrated his speaker system in a ceremony at Copenhagen. But after returning to the United States, he broke with other Magnavox executives over policy matters and resigned from the firm (1925). In 1927 he founded the Jensen Radio Manufacturing Company, originally headquartered in Oakland, California, but soon moved to Chicago. There, with the aid of engineer Hugh Knowles, Jensen worked intensively to eliminate distortion and improve fidelity in sound reproduction. In 1943 disputes with financial backers led once more to his resignation from a firm of his own creation; he subsequently founded Jensen Industries to manufacture phonograph needles. Jensen died in Western Springs, Illinois, on October 26, 1961.
(RARE SIGNED FIRST EDITION dust jacket hardcover, clean te...)
Membership
Jensen was made an honorary Member of the Audio Engineering Society in 1955. he was honoured by the American Institute of Radio Engineers. He was also elected an Extraordinary Member of the Danish Engineering Society.
Connections
Jensen married Vivian Steves in 1912; they had four children. The marriage ended in divorce in 1927, and he married Malvena Oppliger in 1929; they had one child.
Jensen was knighted by the King of Denmark in the Order of the Dannebrog for his achievements. He also received honors from the American Institute of Radio Engineers and the Audio Engineering Society.