1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
September 1930 Radio-Craft[Table of Contents]
People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Radio-Craft was published from 1929 through 1953. All copyrights are hereby acknowledged. See all articles from Radio-Craft.
The name Ernst Frederick Werner Alexanderson (1878-1975) might not seem overly familiar to you, but he is credited with designing the first high frequency alternator for transmitting longwave audio modulation over long distances. His device preceded the spark and arc type transmitters that infamously spewed harmonics and noise all over the spectrum and were therefore a great nuisance when broadcast at high power levels. It was a relatively (for the time) narrowband scheme that permitted more stations to be co-located in a given service area. He went on the develop one of the first successful television projectors as well. Read a short biography on Mr. Alexanderson in the "Men Who Have Made Radio" series by 1930 edition of Radio-Craft magazine.
The Twelfth of a Series
Radio, beneath its innumerable applications, has the fundamental basis of electrical engineering. The latter term may have seemed, oftentimes, a trifle too stately when it was applied to the design of a device of power so low and mechanical structure so simple as that of the earliest radio receiving sets; but the problems of long-distance and commercial radio transmission involve tasks of consummate engineering as well as delicate electrical balancing. It is not enough to perceive clearly radio's fundamental principles; it is necessary to create machinery for their application. Such has been pre-eminently the work of the distinguished electrical engineer pictured here.
Ernst F. W. Alexanderson was born January 25, 1878, in the ancient city of Upsala, in Sweden. His early mechanical bent was encouraged by his father, a professor of classical languages, and he was sent to the Royal Technical University of Stockholm. After post-graduate technological work in Berlin, the young engineer determined to pursue his profession in America. Here, in 1902, he entered the drafting department of the General Electric works at Schenectady; and after two years, won a place on the engineering staff, to the top of which he proceeded to climb rapidly.
Alexanderson soon made his impression on the whole field of electrical motor design and allied machinery. The New Haven railroad undertook electrification, and he designed the single-phase motor for this work. For other purposes, he created the self-exciting alternator, high-voltage D.C. motors, high-voltage synchronous converters, variable-speed induction motors of great power, whose application to the battleship New Mexico marked a revolution in naval design.
Perhaps the best known, however, of his accomplishments in this type of machinery is the invention of the high-frequency alternator; the repercussions of which were more than nationwide. For many years the spark method of radio transmission reigned, until it was threatened by the arc; yet neither of these met the rising demands of radio communication. The idea of creating a generator which should develop radio frequencies, as ordinary machinery does sixty-cycle current, had been more than once suggested. The problem of practicable design, however, seemed insoluble until Alexanderson was successful. A new and striking element was introduced into overseas communication; and to it the inventor added the magnetic amplifier and the multiple tuned antenna, the last perhaps the most important from the standpoint of permanent addition to the radio art.
The rivalry between transoceanic communication systems reached the point when a consolidation of American electrical companies and "wireless" systems was formed, on the suggestion of the late Admiral Bullard, in order to maintain ownership of over-sea "ether lanes" in American hands. Dr. Alexanderson was appointed the first chief engineer of the Radio Corporation, to effect the systematization of its assembled constituents, and the extension of its facilities. "Radio Central," that marvelous linking of the communication offices in New York to the transmitters and receivers, some of them hundreds of miles away was the result. Today telegraph, telephone, and even pictorial messages go out to all quarters of the world, from controls a continent away from the sending aerial.
It was not alone on the large scale that the engineer worked, however. He had to make practical huge generators, and great antenna systems which multiplied the certainty of reception a thousand-fold; but the same researches were to make their mark on home radio devices. Not only did he work on vacuum-tube amplification and modulation for transmission, but his system of tuned radio-frequency reception forms the fundamental patents for the modern radio receiver. By solving the problem of selectivity, it made broadcast reception possible in a zone where broadcasters by the score are competing for the public ear. One of his earliest studies in radio was the problem of the behavior of iron in a magnetic field alternating at radio frequencies and of dielectric hysteresis. One of the by-products of the invention of the alternator is that of the cored high-frequency amplifier.
Not only did the work of Dr. Alexanderson command the respect of his profession, but also the honors, first of the gold medal of the Institute of Radio Engineers, and then of the presidency of that organization in 1921.
In recent years, the most striking of his developments, as chief consulting engineer of the General Electric Company, have been those in the field of television, where he has been steadily building up a technique which seems now, for the first time, to bring sight-at-a-distance out of the laboratory and into commercial possibility. Two years ago, he took television apparatus out of the huge laboratories and set it down in the home; where representatives of the press and public were admitted to see moving images in the little screens of receivers which differed apparently in no other manner from those in their own houses.
This was followed by the public exhibition of television images, almost full size, to the thousands who visited the radio world's fair in New York that year. Those faint, flickering, but unmistakable shadow shapes seemed to bid their watchers wait yet a little longer, and television would be here.
The laboratory of such an inventor is no unobtrusive table in a corner; he who works on a huge scale must have adequate tools. A workbench ninety feet long, lining one side of a lofty room, down the center of which runs a traveling crane; dynamos, generators and the appliances of science on every hand; draftsmen and observers busy everywhere with measurements, sketches and calculations-so an eyewitness sees the sanctum where Dr. Alexanderson presides.
Out of this workshop, a few days ago, came another surprise for the world. The television projector (pictured and described in the previous issue of Radio-Craft) threw upon the screen of a theater, in the view of thousands, moving figures far larger than life, in detail better than ever. The engineer, whose life task has been to make large bodies move faster, has accomplished the same feat with even those incorporeal, phantom reflections of distant actors which he threw into the ether, and caught from it again.
Television had at last turned the corner!
Posted November 19, 2015