engineering

John D. Kraus

John D. Kraus is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand John D. Kraus rather than just read about it. In short: John Daniel Kraus (June 28, 1910 – July 18, 2004) was an American physicist and electrical engineer known for his contributions to electromagnetics, radio astronomy, and antenna theory. His inventions included the helical antenna, the corner reflector antenna, and several other types of antennas.

Key takeaways

John D. Kraus belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect John D. Kraus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of John D. Kraus from memory before moving on to harder problems.

Reference excerpt

John Daniel Kraus (June 28, 1910 – July 18, 2004) was an American physicist and electrical engineer known for his contributions to electromagnetics, radio astronomy, and antenna theory. His inventions included the helical antenna, the corner reflector antenna, 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.

Personal

Kraus was born in 1910 in Ann Arbor, Michigan. He received his Ph.D. in physics from the University of Michigan in 1933. In addition to his professional achievements, he was an amateur radio operator, license w8jk, and made many technical contributions to amateur radio, particularly his development of the close-spaced directional array. His father was scientist Edward Henry Kraus. Before World War II Kraus developed antennas including the corner reflector and w8jk close-spaced array. He also helped construct and operate the University of Michigan 100 ton cyclotron, then the world's most powerful particle accelerator.

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 cyclotron. During World War II he worked on degaussing ships for the United States Navy and on radar countermeasures at Harvard University. After the war, Kraus joined Ohio State University, later becoming the director of the Radio Observatory and McDougal Professor (later Emeritus) of Electrical Engineering and Astronomy. He supervised the Ohio Sky Survey which cataloged over 19,000 radio sources, more than half previously unknown, and later participated in the SETI survey conducted by Bob Dixon.

Sputnik I In 1958, while he was at Ohio State, Kraus used the signal of radio station WWV to track the disintegration of Russian satellite Sputnik 1. 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, 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.

Bibliography Antennas, 1950, 1st edition, published by McGraw-Hill was a textbook in which the helical antenna Kraus invented is described in detail. The book was referred to by many as the Antenna Bible. The second edition also single-handedly authored by Kraus was published in 1988 was a major upgrade of the work, incorporating the latest developments, though lacking some of the details of the first edition, to which the second frequently refers for mathematical deductions. For the third edition Ronald J. Marhefka joined Kraus as author and editor with many chapters written by experts in their field. The book was updated with respect to computer modeling and terahertz waves, and its title was changed to Antennas for all Applications: Antennas for all Applications, Kraus, Ronald J. Marhefka, McGraw-Hill 2002 (ISBN 007123201X). Big Ear 1976, Big Ear Two: Listening for Other-Worlds 1994. Electromagnetics, published by Mc-Graw Hill (ISBN 0071164294) 1953. Our Cosmic Universe 1980. Radio Astronomy, published by Cygnus-Quasar (ISBN 0070353921) 1966. An updated second edition was released in 1986 in a spiral-bound form.

Honors and awards U.S. Navy Meritorious Civilian Service Award, 1946. Elected to Fellow of the IEEE, 1954. Elected to member of the National Academy of Engineering, 1972. Joseph Sullivant Medal from the Ohio State University, 1970. Outstanding Achievement Award, the University of Michigan, 1981. IEEE Centennial Medal, 1984. IEEE Edison Medal, 1985. IEEE Heinrich Hertz Medal, 1990. Twice the Distinguished Achievement Award from the IEEE Antennas and Propagation Society, 1985 and 2003.

See also Reber Radio Telescope Grote Reber Karl Guthe Jansky Astronomical radio source List of textbooks in electromagnetism Wow! signal

References

External links Obituary at bigear.org

Illustrations

Worked examples

Example 1 — a first encounter with John D. Kraus

Start with the simplest possible case. Write down what John D. Kraus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to John D. Kraus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about John D. Kraus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of John D. Kraus

In research: John D. Kraus appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses John D. Kraus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: John D. Kraus is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1910 births, 2004 deaths, 20th-century American engineers, so understanding it makes those chapters shorter.
In everyday life: Look for John D. Kraus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study John D. Kraus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what John D. Kraus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain John D. Kraus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John D. Kraus in simple terms?

Why does John D. Kraus matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study John D. Kraus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on John D. Kraus.