SciTech Tuesday: Radar Jamming Chaff

The effect of jamming on the left side of a German Wurzburg radar display. The target cannot be distinguished from the chaff. Courtesy of IWM.

Today we celebrate the birth of Dr. Fred Whipple, the American astronomer who co-invented a device that cut chunks of tinfoil into fragments. These fragments, known as chaff, were released by allied aircraft to distort enemy radar detection. Dr. Whipple was awarded the Certificate of Merit by President Truman in 1948 for his invention.

Chaff, developed independently in the United States, the United Kingdom, and Germany, could overwhelm radar systems by producing clouds of false echoes masking the location and speed of aircraft. Chaff systems consisted of small strips of aluminum measuring one-half the wavelength of the tracking radar. This length maximizes the backscatter effect, effectively jamming radio waves from identifying target aircraft.

Post by Annie Tête, STEM Education Coordinator