John D. Kraus
Encyclopedia
John Daniel Kraus was an American
physicist
known for his contributions to electromagnetics, radio astronomy
, and antenna
theory. His inventions included the helical antenna
, the corner reflector
, and several other types of antennas. He designed the Big Ear radio telescope
at Ohio State University
, which was constructed mostly by a team of OSU students and was used to carry out the Ohio Sky Survey
. Kraus held a number of patents and published widely.
. He received his Ph.D.
in physics from the University of Michigan
in 1933.
. During World War II he worked on degaussing
ships for the United States Navy
and on radar countermeasure
s at Harvard University
.
After the war, Kraus joined Ohio State University
, later becoming the director of the Radio Observatory and McDougal Professor (Emeritus) of Electrical Engineering and Astronomy.
Sputnik I. Kraus knew that a meteor entering the upper atmosphere leaves in its wake a small amount of ionized air. This air reflects a stray radio signal back to Earth, strengthening the signal at the surface for a few seconds. This effect is known as meteor scatter. Kraus predicted that what was left of Sputnik would exhibit the same effect, but on a larger scale. His prediction was correct; WWV's signal was noticeably strengthened for durations lasting over a minute. In addition, the strengthening came from a direction and at a time of day that agreed with predictions of the paths of Sputnik's last orbits. Using this information, Dr. Kraus was able to draw up a complete timeline of Sputnik's disintegration. His data also led him to conclude that satellites do not fail as one unit. Instead, his data indicated that the spacecraft broke up into its component parts as it moved closer to the Earth.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
known for his contributions to electromagnetics, radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
, and antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
theory. His inventions included the helical antenna
Helical antenna
A helical antenna is an antenna consisting of a conducting wire wound in the form of a helix. In most cases, helical antennas are mounted over a ground plane. The feed line is connected between the bottom of the helix and the ground plane...
, the corner reflector
Corner reflector
A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects waves back directly towards the source, but shifted . Unlike a simple mirror, they work for a relatively wide-angle field of view. The three intersecting surfaces often have...
, and several other types of antennas. He designed the Big Ear radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
at Ohio State University
Ohio State University
The Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...
, which was constructed mostly by a team of OSU students and was used to carry out the Ohio Sky Survey
Ohio Sky Survey
The Ohio Sky Survey was an astronomical survey of extragalactic radio sources. Data were taken between 1965 and 1971 using the Big Ear radio telescope at the Ohio State University Radio Observatory , also known as the "Big Ear Radio Observatory "....
. Kraus held a number of patents and published widely.
Personal
Kraus was born in 1910 in Ann Arbor, MichiganAnn Arbor, Michigan
Ann Arbor is a city in the U.S. state of Michigan and the county seat of Washtenaw County. The 2010 census places the population at 113,934, making it the sixth largest city in Michigan. The Ann Arbor Metropolitan Statistical Area had a population of 344,791 as of 2010...
. He received his Ph.D.
Ph.D.
A Ph.D. is a Doctor of Philosophy, an academic degree.Ph.D. may also refer to:* Ph.D. , a 1980s British group*Piled Higher and Deeper, a web comic strip*PhD: Phantasy Degree, a Korean comic series* PhD Docbook renderer, an XML renderer...
in physics from the University of Michigan
University of Michigan
The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...
in 1933.
Career
Following the completion of his doctorate, Kraus was a member of the research team in nuclear physics at the University of Michigan, helping to design and build the school's new 100-ton cyclotronCyclotron
In technology, a cyclotron is a type of particle accelerator. In physics, the cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicularly to the direction of a uniform magnetic field, i.e. a magnetic field of constant magnitude and direction...
. During World War II he worked on degaussing
Degaussing
Degaussing is the process of decreasing or eliminating an unwanted magnetic field. It is named after Carl Friedrich Gauss, an early researcher in the field of magnetism...
ships for the United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
and on radar countermeasure
Countermeasure
A countermeasure is a measure or action taken to counter or offset another one. As a general concept it implies precision, and is any technological or tactical solution or system designed to prevent an undesirable outcome in the process...
s at Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
.
After the war, Kraus joined Ohio State University
Ohio State University
The Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...
, later becoming the director of the Radio Observatory and McDougal Professor (Emeritus) of Electrical Engineering and Astronomy.
Sputnik I
In 1958, while he was at Ohio State, Dr. Kraus used the signal of radio station WWV to track the disintegration of Russian satelliteSatellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
Sputnik I. Kraus knew that a meteor entering the upper atmosphere leaves in its wake a small amount of ionized air. This air reflects a stray radio signal back to Earth, strengthening the signal at the surface for a few seconds. This effect is known as meteor scatter. Kraus predicted that what was left of Sputnik would exhibit the same effect, but on a larger scale. His prediction was correct; WWV's signal was noticeably strengthened for durations lasting over a minute. In addition, the strengthening came from a direction and at a time of day that agreed with predictions of the paths of Sputnik's last orbits. Using this information, Dr. Kraus was able to draw up a complete timeline of Sputnik's disintegration. His data also led him to conclude that satellites do not fail as one unit. Instead, his data indicated that the spacecraft broke up into its component parts as it moved closer to the Earth.
Honors and awards
- U.S. Navy Meritorious Civilian Service AwardNavy Meritorious Civilian Service AwardThe Navy Meritorious Civilian Service Award is awarded to civilian employees in the Department of the Navy for meritorious service or contributions resulting in high value or benefits for the Navy or the Marine Corps...
, 1946. - Elected to Fellow of the IEEE, 1954.
- Elected to member of the National Academy of EngineeringNational Academy of EngineeringThe National Academy of Engineering is a government-created non-profit institution in the United States, that was founded in 1964 under the same congressional act that led to the founding of the National Academy of Sciences...
, 1972. - Joseph Sullivant Medal from the Ohio State UniversityOhio State UniversityThe Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...
, 1970. - Outstanding Achievement Award, the University of Michigan, 1981.
- IEEE Centennial MedalIEEE Centennial MedalThe IEEE Centennial Medal was a medal minted and awarded in 1984 to celebrate the Centennial of the founding of the Institute of Electrical and Electronics Engineers in 1884.The medal obverse shows 1884 in calligraphic writing and 1984 in an LCD font...
, 1984. - IEEE Edison MedalIEEE Edison MedalThe Edison Medal is presented by the IEEE "for a career of meritorious achievement in electrical science, electrical engineering or the electrical arts." It is the oldest and most coveted medal in this field of engineering in the United States. The award consists of a gold medal, bronze replica,...
, 1985. - IEEE Heinrich Hertz MedalIEEE Heinrich Hertz MedalThe IEEE Heinrich Hertz Medal was a science award presented by the IEEE for outstanding achievements in the field of electromagnetic waves. The medal was named in honour of German physicist Heinrich Hertz, and was first proposed in 1986 by IEEE Region 8 as a centennial recognition of Hertz's work...
, 1990. - Twice the Distinguished Achievement Award from the IEEE Antennas and Propagation Society, 1985 and 2003.
External links
See also
- Reber Radio TelescopeReber Radio TelescopeReber Radio Telescope is a parabolic radio telescope. It is significant for its pioneering of radio astronomy.Grote Reber was an amateur astronomer who built this telescope in Illinois in 1937, implementing a proposal of Karl Jansky, the discoverer of radio waves emanating from the Milky Way...
- Grote ReberGrote ReberGrote Reber was an amateur astronomer and pioneer of radio astronomy. He was instrumental in investigating and extending Karl Jansky's pioneering work, and conducted the first sky survey in the radio frequencies...
- Karl Jansky
- Astronomical radio source