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SCR-268 radar

SCR-268 radar is a science 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 SCR-268 radar rather than just read about it. In short: The SCR-268 (short for Set, Complete, Radio no. 268) was the United States Army's first radar system. Introduced in 1940, it was developed to provide accurate aiming information for antiaircraft artillery and was also used for gun laying systems and directing searchlights against aircraft.

SCR-268 radar — main illustration
SCR-268 radar — illustration

Key takeaways

  • SCR-268 radar belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect SCR-268 radar to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of SCR-268 radar from memory before moving on to harder problems.

Reference excerpt

The SCR-268 (short for Set, Complete, Radio no. 268) was the United States Army's first radar system. Introduced in 1940, it was developed to provide accurate aiming information for antiaircraft artillery and was also used for gun laying systems and directing searchlights against aircraft. The radar was widely utilized by both Army and Marine Corps air defense and early warning units during World War II. By the end of World War II the system was already considered out of date, having been replaced by the much smaller and more accurate SCR-584 microwave-based system.

Development The Signal Corps had been experimenting with some radar concepts as early as the late 1920s, under the direction of Colonel William R. Blair, director of the Signal Corps Laboratories at Fort Monmouth, New Jersey. While most of the Corps' efforts revolved around infra-red detection systems (a popular idea at the time), as well as a newer generation of sound detectors, they also maintained a small program of research on microwave radars based on the "beat principle", in which an aircraft would cause two signals to interfere. Low generator efficiency and a lack of ranging capability made these efforts impractical. In 1935 one of Blair's recent arrivals, Roger B. Colton, convinced him to send an engineer to investigate the US Navy's CXAM radar project after the bureau of Standards requested a proposal for radio detection of aircraft. The navy's system traced its development from experiments conducted by Albert H. Taylor and Leo C. Young at the United States Naval Research Laboratory in the early 1920s. William D. Hershberger duly went to see what they had, and returned an extremely positive report. Gaining the support of James B. Allison, the Chief Signal Officer, they managed to gather a small amount of funding and "stole" some more from other projects. By December 1936 they had a working 3 meter prototype, which they continued to work on and improve. In November 1938 they were able to show the 1.5 meter prototype in a convincing demonstration for Hap Arnold. After failing to find their target Martin B-10 bomber where it was supposed to be, they started "hunting" for it and found it 10 miles off course. The radar fed pointing data to a team operating a searchlight, and when it was turned on the bomber was seen to be centered in the beam. It was later learned that the target had been blown off course, making the demonstration all the more impressive. Development of this system was slowed to some degree when a long range early-warning radar became a higher priority and parts of the prototype were salvaged for the SCR-270 they were building. Nevertheless, the system entered production at Western Electric about the same time as the -270 in 1939. The radar entered service in 1940, and about 3100 were produced by the end of the war. In 1944, the SCR-268 radar unit was beginning to be replaced by the SCR-584 radar. The SCR-268 was able to acquire and direct guns, or searchlights, on a target with a single piece of equipment.

Description

… excerpt ends here. Continue reading the full article.

Illustrations

SCR-268 radar illustration
SCR-268 radar: Three soldiers of the United States Army operate a radar used by the 90th Coast Artillery (Antiaircraft, Semimobile, Colored) in Casablanca
Three soldiers of the United States Army operate a radar used by the 90th Coast Artillery (Antiaircraft, Semimobile, Colored) in Casablanca
SCR-268 radar: Oscilloscope operators with range scope at left, azimuth scope in middle, and the elevation scope at right
Oscilloscope operators with range scope at left, azimuth scope in middle, and the elevation scope at right

Worked examples

Example 1 — a first encounter with SCR-268 radar

Start with the simplest possible case. Write down what SCR-268 radar claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 SCR-268 radar 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 SCR-268 radar 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 SCR-268 radar

In research
SCR-268 radar appears in science 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 SCR-268 radar 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
SCR-268 radar is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gun laying radars, Military electronics of the United States, Military equipment introduced from 1940 to 1944, so understanding it makes those chapters shorter.
In everyday life
Look for SCR-268 radar 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 SCR-268 radar in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what SCR-268 radar means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain SCR-268 radar out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SCR-268 radar in simple terms?

The SCR-268 (short for Set, Complete, Radio no. 268) was the United States Army's first radar system. Introduced in 1940, it was developed to provide accurate aiming information for antiaircraft artillery and was also used for gun laying systems and directing searchlights against aircraft.

Why does SCR-268 radar matter?

Because it connects several science 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 SCR-268 radar?

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 SCR-268 radar.

Tags

  • Gun laying radars
  • Military electronics of the United States
  • Military equipment introduced from 1940 to 1944
  • Military radars of the United States
  • Military radars of the United States Marine Corps
  • World War II radars

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