In a nutshell
EG Bowen was head of the team that tackled and solved the problems of how to operate radar inside an aeroplane. Before this, radar was operated entirely on the ground and required equipment that filled a small house. Now all that traffic police need to check road speed is a radar gun.
In 1935 Bowen joined a small team of researchers who were studying a new development, only later called radar, which became extremely important in defending Britain in the Second World War. Nine years later he moved to Australia, where he was responsible for two especially important developments:
- The construction of a huge radiotelescope in Parkes, New South Wales
- A remarkable effort to improve rainfall. Just the job for a native of wet Wales!
RADIO DETECTION AND RANGING
We're familiar with films that show radar screens where the sweeping arm shows where ships and other objects are. The sweeping arm on the screen links with the rotating antenna, which you can see on ships, transmitting the radio waves.
The basic principle is like an echo. If you shout near a wall or under a bridge the sound of the shout (a pulse of sound waves) reflects from the wall and you'll hear the shout again as an echo. In radar systems the 'shout' is a pulse of radio waves of short wavelength, which is sent out by equipment called the transmitter. The 'wall' is any object (plane, ship, land) that reflects the radio waves. The 'echo' is a pulse of radio waves which is 'heard' by equipment called the detector.
The outgoing and returning pulses are displayed as 'blips' on a screen. If you know the wavelength of the outgoing pulse, the speed of radio waves in air and the time interval between transmission and detection (out and back), it's possible to work out how far away (the range) the reflecting object is.
Today's radar is vital for planes, ships and submarines to be able to navigate safely, especially when visibility's bad.