Ekco SH25 radio, 1932.
© Science Museum / Science & Society Picture Library
A five-valve domestic receiver in an Art Deco Bakelite case featuring large circular tuning scale around a metal speaker grille depicting a treescape. The SH25 was the first superheterodyne radio made by E K Cole and Co Ltd. In 1917, Edward Howard Armstrong (1890-1954) developed the superheterodyne electronic circuit, which significantly improved the sensitivity and selectivity of radio receivers over a wide range of frequencies, making amplifier tuning unnecesary. This made the task of tuning the radio receiver to different stations much more simple and straightforward. Radios with superheterodyne circuit technology are commonly known as 'superhets'.