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Early History of Radar

It wasn't until 1942 that the US Navy coined the official acronym for modern day RADAR, which stands for radio detecting and ranging. However, the scientific concept of radar developed millions of years ago in nature as the ultrasonic sensor of a bat. Bats release a short "cry" through their nasal passages and receive its echo through antennae-like ears. Interestingly, the oldest radar used as a warning system also evolved in nature as defense against bats. Tiger moths, a staple diet for bats, have evolved with ears equipped to detect and scramble a bat’s radar system as a method of evading attacks.

First Radars

Human involvement with radars first began around the beginning of the 20th century. In 1904, German inventor, Christian Hulsmeyer, acquired a patent for the Telemobiloskop or, the Remote Object Viewing Device. This device was developed as a tool to detect and avoid ship collisions. Unfortunately, Hulsmeyer’s creation never really caught on and the Telemobiloskop quickly fell into marketing oblivion.

Despite Hulsmeyer’s failure, the theory behind primitive radar technology continued to advance and change form and function. Radio transmissions, remote radio measuring techniques and object detection devices throughout the 1920s and ‘30s all utilized the concept of radar. Experiments in the ‘20s and ‘30s at the US Naval Research Labs by Dr. Alfred Hoyt Taylor and Leo C. Young demonstrated rudimentary CW detection of ship and aircraft targets. Limitations of technology held back development until Robert Page’s breakthrough demonstration of pulsed radar in 1936.

A year earlier, in Great Britain, another breakthrough, the so-called Daventry Experiments of Sir Robert Watson-Watt, demonstrated detection of aircraft at over eight miles. This led to the immediate development of the first operational radar system know as Chain Home, a series of radar towers along the south coast of England which were deployed in 1937.

Radar Use

By 1939 Britain, France, Germany, Russia, Switzerland and the US were all counted among countries with developed and functional radars.

World War II marked the first organized use of radars during battle. Throughout the war, several countries relied upon their radars to prevent attack as well as to search and destroy targets. Significant efforts continued to enhance the rudimentary science. The refinement of the magnetron enabled higher frequency (3GHz) performance leading to higher resolution and more compact radar systems; thus opening a range of applications for ground, land and sea-based systems.

In spite of the rapid development of radars, they were still not fully understood, nor did their use have well developed concepts of operation. A significant missed opportunity in history for radars occurred on December 7, 1941 or Pearl Harbor Day. On that day, radar operators actually detected the presence of invading squadrons approaching the Hawaiian Islands. However, when they reported their findings their superiors quickly dismissed the observations. Had senior military staff trusted in less tenured personnel and their radar technology, that historical day may have had an entirely different ending.

Summary

By the end of World War II most of the radar technologies used today were in place, though they were dependent upon the limited technical means of the time. Chirp radar, synthetic aperture radar and monopulse techniques were all in use. Future technical developments in magnetrons, electronics and signal process would bring radar forward into the second half of the century.

• History of Radar