A Gnat Crystal Radio
X-ray image of a Gnat NMK CI crystal radio receiver (National Wireless & Electric Co., London, UK) from the 1920s. By moving the cat’s whisker over the crystal set, the user could locate sensitive spots that yielded a clear radio signal. The crystal radios were the first reliable and widely available electronic mass media technology. Image obtained with a Nikon XTH225 ST system.
—Herminso Villarraga-Gómez, Optical Society of America, USA
