Alexanderson Day - humble the great inventor

Source: www.sciencephoto.com

Few know about Ernst Alexanderson. The name of this very talented engineer lost in the glare of the names of his illustrious colleagues - Thomas Edison, Guillermo Marconi, Nikola Tesla, Alexander Popov ... However, on account of Alexanderson 345 patents related to Electrical and Electronics Engineers, and he is considered one of the pioneers of radio and television; last he got his patent, at the age of 89 years! Unlike the famous inventors whose names on everyone's lips, Alexanderson not seek fame, was not involved in high-profile scandals and stories, and simply worked, inventing and creating a very necessary and important for the emerging electronics devices.




Ernst Frederick Werner Alexanderson was born in Sweden in 1878. In 1902 he emigrated to America, where he began working for the company General Electric. In 1904, at age 26, he created probably the most spectacular in the history of the car radio, which was intended for serious work and not fun respectable audience (sim was throw a pebble in the garden of St. Nicholas "our everything" Tesla) ... This machine - mechanical generator of radio frequency vibrations - called the "alternator".



Source: www.tekniskamuseet.se

Alexanderson alternator to generate the signal frequency up to 100 kHz. Clearly, turn the rotor of the machine up to a speed impossible. Alternator shaft was rotated at a speed of the order of several thousand revolutions per minute, but due to the special configuration of the coils of the generator output we obtain the desired high frequency. The design is the alternator has been very successful. They were used on the radio until the 60s of the last century, that is, even when there were already busy using tube and generators. The disadvantage of these machines were large size and weight, and because of this they can not be installed on ships.
It Alexanderson alternator allowed to carry the world's first voice radio broadcast December 24, 1906 with the US Atlantic coast. Actually, for this purpose it was created, not having radiofrequency generator undamped oscillations, it is impossible to transmit the voice over the radio.



Source: wikipedia.org

Technical progress is inexorable. With the advent of more sophisticated generators alternators sent to landfill (and maybe a meltdown). And today in the world there was only one working alternator. It is set in a building Grimetonskoy station that is close to the Swedish city of Varberg. This station can be called the memorial, it was founded by Ernst Alexanderson himself in 1922, being at that time the chief engineer On Air America (RCA). In his honor, all the radio equipment is maintained in working order.



Source: alexander.n.se



Source: flickr.com

Day 2 July is considered day Alexanderson. Every year, in the near to this date Sunday alternator starts, and, just like many years ago, at a frequency of 17 kilohertz 2 Morse code transmitted in the broadcast station call letters SAQ and congratulations on the occasion. What could be a better recognition of the merits of an engineer than he created the same and still works equipment?





Source: alexander.n.se

This year Grimetonskaya radio station will air on 29 June. The transmitter will include a 8:30 UTC, and the transfer will begin at 9:00 UTC. Ceremony again in 11:30 UTC.
Unfortunately, without proper training to listen to broadcast "live" impossible. Need superlong antenna and receiver, and there is no guarantee that a good distance away from the radio station, for example, in Moscow, something generally caught. But the opportunity to hear the voice of the equipment that is forever a thing of the past, making this day is probably the most touching Technical holiday.
Ernst Alexanderson died in 1975. For his services he was awarded the Medal of Honor and the Edison Institute of Radio Engineers (now IEEE), and after the death of Alexanderson name was entered in the books of the National Inventors Hall of Fame (NIHF) and the Hall of Fame Consumer Electronics Association (CEA). Grimetonskaya radio station joined the list of UNESCO World Heritage.



Source: ieeexplore.ieee.org

In conclusion - two videos: Alexanderson alternator operation and signal reception Grimetonskoy radio.



Source: habrahabr.ru/post/227609/