亚博绑定银行卡有危险吗the name of reginald aubrey fessenden is not as widely known as it deserves. also he is often quoted as being an american, a fact which canadians hotly contest as fessenden was born in canada.
亚博绑定银行卡有危险吗in his life, r a fessenden achieved a considerable amount, pushing back the frontiers of radio or wireless technology of the day. he held many firsts, and without his drive and insight, radio technology would have developed considerably more slowly than it did.
亚博绑定银行卡有危险吗fessenden's most notable achievements include the first audio radio transmission in 1900, the first two way transatlantic transmission in 1906 and the first broadcast of entertainment, also in 1906.
亚博绑定银行卡有危险吗many of fessenden's developments and achievements were well ahead of their time, and showed his insight, not only into the technical aspects of radio, but also the commercial elements as well.
Fessenden's early years
亚博绑定银行卡有危险吗reginald aubrey fessenden was born on 6th october 1866 in the town on east bolton, quebec, canada. he was the eldest of the four children of elisha and clementina fesseden. his mother was a minister in the church of england in canada and as a result the family moved several times during r a fesseden's childhood.
the young reginald fessenden was intelligent and was able to learn quickly. in 1877, at the age of 12, he entered trinity college in port hope ontario, and two years later he moved to bishop's college (now bishop's university) in lennoxville, quebec. however reginald fessenden left at the age of 18 having nearly completed his degree, but not gaining the final award.
as a result of leaving bishop's college with no formal qualification, fessenden found it more difficult to move forward. however he managed to secure a position at whitney institute in bermuda as the sole teacher and principal. while he was in bermuda he became friendly with helen trott to whom he later became engaged and in september 1890 they were married.
亚博绑定银行卡有危险吗although reginald fessenden had been granted a mathematical scolarship at bishop's college, much of his education had a classics orientation and this did not suit him for a career in the new and developing area of electrical sciences. to improve his chances of success, he moved to new york in 1886 with the hope that he might be able to secure some employment with edison's company. his initial attempts were unsuccessful, but after pursuing opportunities with edison he was hired as an assistant tester for the edison machine works, a company laying underground electrical mains cables in new york.
亚博绑定银行卡有危险吗fessenden showed an aptitude and keenness for the work and was promoted so that in 1886 he started to work directly for edison himself at the new "invention factory" as it was termed at west orange , new jersey. here fessenden was involved in a number of sciences and he soon gained a considerable degree of experience.
unfortunately the edison company faced severe financial problems in 1890 and had to lay off a large number of employees and fessenden was included in this number.
as a result of his experience with edison, fessenden was able to find employment relatively easily. he worked for a number of companies, but in 1892 was appointed as professor at the newly formed department of electrical engineering at purdue university in indiana. later he moved from here to the western university of pennsylvania, which is now the university of pittsburgh.
Work at the Weather Bureau
亚博绑定银行卡有危险吗during the late 1890s marconi started to hit the headlines with his experiments that were pushing back the frontiers of wireless transmission technology. marconi was something of a showman and was able to capture the news headlines. reginald fessenden too, started to become interested in wireless technology and as a result he started his own experimentation in this field, initially looking at some of the equipment used.
亚博绑定银行卡有危险吗the possibilities that early wireless technology appeared to offer fascinated fessenden. in 1900 he left pittsburgh to work for the united states weather bureau. fessenden saw the possibility of using wireless transmissions to link a network of coastal stations together rather than using a wired telegraph link. for his work, fessenden was based at cobb island on the potomac river in maryland
Fessenden made several major advances, in particular in the area of receiver design as this was one of the major limitations of the time. He first developed a new form of detector known as the barretter detector, and this was followed by the electrolytic detector which remained in used for many years.
亚博绑定银行卡有危险吗another major milestone, during this period was that fessenden succeeded in making what is believed to be the first wireless transmission carrying audio sound. the experiment took place on 23rd december 1900 and the signal was received over a mile away.
亚博绑定银行卡有危险吗the equipment used by fessenden was a spark transmitter with an interrupted to provide a continuous series of sparks. the output of the generator was modulated by placing a carbon microphone directly in the antenna lead. although very crude by today's standards, the system nevertheless worked. it is reported that using the transmitter fessenden spoke loudly into the microphone saying: "hello test, one ,two, three, four. is it snowing where you are mr thiessen? if it is telegraph back and let me know." his assistant immediately returned a telegraph message to indicate he had heard fessenden and that it was also snowing, which was hardly suprising as he was only a mile away. the received signal was described as being perfectly understandable, except that it was accompanied by a loud disagreeable noise resulting from the irregularity of the spark.
fessenden worked to improve the system over the following two years and more. by 1903 he had succeeded in obtaining reasonably satisfactory speech transmission by creating an almost continuous arc. however the system was still plagued by the very unpleasant sound of the arc itself.
亚博绑定银行卡有危险吗one of the other major advances made by fessenden was the development of the heterodyne principle. he undertook experiments with this in 1901, but in view of the state of wireless technology, it was well ahead of its time and was not used for over ten years afterwards as it required the generation of stable continuous wave signals and these were not practicable until the thermionic valve or vacuum tube became available.
亚博绑定银行卡有危险吗the network of wireless stations expanded and started to prove its worth. however during this time legal arguments started over the possession of the patents. as a result of this, fessenden's time at the weather bureau came to an end in august 1902.
Fessenden at NESCO
the work that reginald fessenden had undertaken at the weather bureau had not gone un-noticed. some saw the value of the work that he had undertaken and sought to enable him to carry it on. hay walker jr, and thomas given financed the formation of a company named national electric signalling company based in massachusetts. under the auspices of this company, fessenden would be able to carry out research into several projects that would have a variety of applications.
as part of the development programme for long distance communications it was decided to set stations that would enable the first two way transatlantic contact to be established and a service to be introduced thereafter. although marconi had made the first transatlantic transmission in 1901, the transmission was only in one direction. stations were set up at brant rock in the usa and another in scotland at a location named macrihanish. the result was that in january 1906 the first two way transatlantic communication was established. unfortunately the full commercial service was not able to be introduced because the tower collapsed on 6th december 1906 when contractors were working on the steel guy ropes. the investment required to re-establish the station was felt to be too large and the service was abandoned.
亚博绑定银行卡有危险吗another major area of work was the development of a high frequency alternator. this would be able to provide a means of generating a continuous wave signal. fessenden had first worked on the idea in 1900 and even when the first device was delivered in 1903 it would only operate up to a frequency of 10 khz. a second alternator was ordered and eventually delivered in 1905, and the company that made it stated that it would not operate above 10 khz. as a result fessenden himself set about building an alternator that would operate at the frequencies he wanted. he used some parts of the one that was delivered to him and by late 1906 he had a machine that would operate at 75 khz and developed an output power of 500 watts. this enabled him to transmit the continuous wave signals he needed.
fessenden modulated his hf alternators in the same way he had his previous transmitters by placing a carbon microphone in the antenna lead. one night in november 1906 the station at brant rock was in communication with another at plymouth, ma, usa. however this transmission was heard on the other side of the atlantic in macrihanish. then on 24th december 1904 fessenden and his assistants presented the first radio broadcast. the broadcast included a speech by fessenden along with him playing handel's largo in the violin. the broadcast was heard by stations as far away as the west indies, and it was repeated n new year's eve.
亚博绑定银行卡有危险吗fessenden also instigated a christmas broadcast. he describes what happened.
亚博绑定银行卡有危险吗"... first a short speech by me saying what we were going to do, then some phonograph music.... then came a violin solo by me ... which i sang one verse of, in addition to playing the violin, though the singing, of course, was not very good. then came the bible text, glory to god in the highest and on earth peace to men of good will, and we finally wound up by wishing them a merry christmas and then saying that we proposed to broadcast again on new year's eve. "
亚博绑定银行卡有危险吗after fessenden left nesco he did not work directly on radio again, but he did continue to work on other projects and inventions. he became particularly interested in sonar and in methods of detecting icebergs. at the outbreak of world war 1 he volunteered his services to the canadian government worked in london england on methods of detecting artillery, as well as means to detect enemy submarines.
亚博绑定银行卡有危险吗after the war he continued to investigate a wide variety of ideas, refining some of his work on sonar as well as investigating seismology for oil wells, and inventing a fathometer.
as a result of his work, reginald fessenden held over 250 patents, but despite this his name was never really given the recognition that it should have received. however he did receive the scientific american gold medal in 1929.
亚博绑定银行卡有危险吗reginald fessenden managed to settle a lawsuit with rca over patent rights and using the money he gained he bought a small estate on the island of bermuda where he spent the rest of his days. he died there in 1932 and is interred in the cemetery of st mark's church.
reginald fessenden is certainly one of the unsung pioneers of wireless and radio technology. although marconi received much of the limelight with his work, r a fessenden had a might greater insight into the workings of radio technology. he achieved many "firsts". he was the first to develop a method of generating a continuous wave signal and to use it. he was the first to transmit voice, and to make a sound broadcast. he developed and was the first to use the hererodyne principle that forms the basis of almost every radio today. he was the first to establish two-way communication across the atlantic, and to send a voice signal across the atlantic. in many ways, reginald fessenden made huge contributions to the technology of radio, and yet he is comparatively little known. even when people do recognise his name, he is often thought of as an american, whereas in fact he came from canada.
More Famous Scientists in Electronics and Radio:
Volta Ampere Armstrong Appleton Babbage Bardeen Brattain Edison Faraday R A Fessenden Fleming Heaviside Hertz Ohm Oersted Gauss Hedy Lamarr Lodge Marconi Maxwell Morse H J Round Shockley Tesla
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