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Summer 2009 Issue |
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Amateur Radio and the Cosmos |
Photo 1. Shown are Bell Labs scientists P. K. Tien (right), D. McNair (left), and H. L. Hodges (center). They are examining their new triode lasers (there are two shown) which allowed laser light intensity to be modulated using an internal grid. (Source: From Semaphore to Satellite, published by the ITU in 1965)
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As a young boy growing up near the Bell Telephone Laboratories in the 1960s, it was hard to appreciate what went on behind those brick walls. Situated on the first ridge of the Watchung Mountains, with a nature preserve to the rear and an expansive manicured lawn to the front, the sprawling campus of the Murray Hill, New Jersey facility and its otherwise unassuming tan buildings provided little clue as to what went on inside. Although history would reveal that “Bell Labs” was behind the Telstar satellite, the first transistor, the touch tone, video and cellular telephones, the laser, fiber optics, and software developments such as the Unix operating system and the C programming language, such things didn’t achieve public recognition until years later.
Even the people who worked at Bell Labs and
lived in the surrounding neighborhoods didn’t talk much about what went on
there. It was a curious thing that your next-door neighbor could be a
policeman, a carnation grower, or a world-famous radio astronomer. Indeed,
George C. Southworth, inventor of the waveguide and one of the first
persons to detect radio emissions from the Sun, lived just around the
corner, something I only just came to realize. Still, Bell Labs did invest
in public relations, as my classmates and I well remember. Although much of the work at Bell Labs would eventually receive widespread public recognition, such as the first television broadcasts using satellites, much of the technology and achievements were appreciated more in technical circles than by the general public. Nowhere is that more evident than in the world of radio astronomy. Starting in 1931, it was a Bell Labs radio engineer by the name of Karl Jansky who first discovered radio waves of extraterrestrial origin. Assigned to investigate sources of noise affecting overseas phone communications, Jansky directed a carpenter in the construction of a rotating wooden frame supporting an array of metal tubes and glass insulators. Photo 2 shows a replica of the Jansky antenna that is on display at the National Radio Astronomy Observatory in Green Bank, West Virginia. Jansky’s antenna was of the Bruce design, the namesake of yet another Bell Labs employee, Edmund Bruce, who patented this design as illustrated in photo 3.
Jansky’s version used wheels from a Model T to
rotate the antenna on a brick track, thus allowing him to isolate the
direction of various noise sources. At the suggestion of George C.
Southworth, Jansky plotted out his data, making the daily patterns of
static more clearly visible. As a result, Karl came to recognize how one
pattern peaked every 23 hours 56 minutes, or 4 minutes earlier each day.
This corresponds to the movement of the Earth with respect to the stars,
not the Sun, a clear indication that Jansky’s static originated beyond our
solar system. Jansky later concluded that this noise was coming from the
Milky Way galaxy itself. |
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