Crystal Clear: Vintage American Crystal Sets, Crystal Detectors, and Crystals (1)

This book revisits the era of the simple crystal radio set when a "cat's whisker", piece of galena and a coil of wire were all that was needed to tune in a radio signal. It contains hundreds of photos and magazine ads identifying thousands of crystal radios and detectors made in the U.S. from 1920 to 1950. It gives company histories of three of the most influential manufacturers: Wireless Specialty Apparatus Company, RCA and Philmore Manufacturing.