RADAR (Radio Detection and Ranging) is a technology invented in the 1930s to detect distant objects, mostly aircraft and ships. Since detection is done by receiving radio waves reflected from the target, RADAR works the same by day and night and in all weather, which makes it a revolutionary long range observation tool, both military, and after World War 2 also civilian.
RADAR works essentially in the same way that a bat uses sound to "see" in total darkness. The RADAR transmitter produces strong (kilowatts) and extremely short pulses of radio energy. The pulses are transmitted thru the air to a known direction by a directional antenna. When pulses hit an object, such as an aircraft, a ship, or the ground, they are reflected from it. The reflections are received by the RADAR antenna, and converted by a receiver to an electric signal that can be displayed to the operator. Since the speed of the signal is the speed of light, the time between the transmission and the reception of a pulse indicates the distance of the target and together with knowing the direction at which the antenna transmits, the position of the detected target is known.
Initially radars were equipped with display devices like those in an electronics lab (Oscilloscope), but later more operationally useful devices were invented, particularly the PPI (Plan Position Indicator) which is the familiar RADAR display in which a circular display shows a beam which rotates with the rotating RADAR antenna, and marks with light the positions of detected targets relative to their range.
From military point of view there are basically two types of RADAR, used for detection and for fire control.
Detection radars are used to create a RADAR map of all objects in all directions and often as far as possible. They are mostly used for purposes such as early warning detection of aircraft and ships, ground controlled intercept of aircraft, which is done by directing fighter aircraft to detected incoming aircraft, and mapping of the ground terrain for navigation and targeting, mostly by bombers.
The greatest advantage of using RADAR is that it denies the enemy of the ability to use the element of surprise, of being hidden by distance, by night or by clouds until it's too late to defend against it or to attack it before it disappears.
During World War II, radar played a critical role in the British victory in the Battle of Britain, an aerial battle fought largely between August 1940 and the end of that year. In August of 1940 Britain stood alone in the war in Europe, the German army having defeated Britain’s Polish allies in September of 1939, and the French in June of 1940. By August, Hitler had given up attempts to persuade the British to sign a peace treaty favorable to Germany. He started planning an invasion of Great Britain, but first he had to deal with the British air forces. Hitler had reason to be optimistic. The British had only 800 aircraft to try to hold back the onslaught of over 3,000 German planes. The British victory in this battle was largely due to a series of radar stations that had been built along the southern and eastern coasts of Britain in 1939. These radar stations enabled the British to determine the direction, altitude, and speed on oncoming German aircraft while they were still 50 to 60 miles away, and thus concentrate their limited fighter forces against them.
RADAR works essentially in the same way that a bat uses sound to "see" in total darkness. The RADAR transmitter produces strong (kilowatts) and extremely short pulses of radio energy. The pulses are transmitted thru the air to a known direction by a directional antenna. When pulses hit an object, such as an aircraft, a ship, or the ground, they are reflected from it. The reflections are received by the RADAR antenna, and converted by a receiver to an electric signal that can be displayed to the operator. Since the speed of the signal is the speed of light, the time between the transmission and the reception of a pulse indicates the distance of the target and together with knowing the direction at which the antenna transmits, the position of the detected target is known.
Initially radars were equipped with display devices like those in an electronics lab (Oscilloscope), but later more operationally useful devices were invented, particularly the PPI (Plan Position Indicator) which is the familiar RADAR display in which a circular display shows a beam which rotates with the rotating RADAR antenna, and marks with light the positions of detected targets relative to their range.
From military point of view there are basically two types of RADAR, used for detection and for fire control.
Detection radars are used to create a RADAR map of all objects in all directions and often as far as possible. They are mostly used for purposes such as early warning detection of aircraft and ships, ground controlled intercept of aircraft, which is done by directing fighter aircraft to detected incoming aircraft, and mapping of the ground terrain for navigation and targeting, mostly by bombers.
The greatest advantage of using RADAR is that it denies the enemy of the ability to use the element of surprise, of being hidden by distance, by night or by clouds until it's too late to defend against it or to attack it before it disappears.
During World War II, radar played a critical role in the British victory in the Battle of Britain, an aerial battle fought largely between August 1940 and the end of that year. In August of 1940 Britain stood alone in the war in Europe, the German army having defeated Britain’s Polish allies in September of 1939, and the French in June of 1940. By August, Hitler had given up attempts to persuade the British to sign a peace treaty favorable to Germany. He started planning an invasion of Great Britain, but first he had to deal with the British air forces. Hitler had reason to be optimistic. The British had only 800 aircraft to try to hold back the onslaught of over 3,000 German planes. The British victory in this battle was largely due to a series of radar stations that had been built along the southern and eastern coasts of Britain in 1939. These radar stations enabled the British to determine the direction, altitude, and speed on oncoming German aircraft while they were still 50 to 60 miles away, and thus concentrate their limited fighter forces against them.