Name Charles Apgar | ||
Charles Apgar (died August 17, 1950) was an American amateur radio operator who is known for making the earliest surviving recordings of a radio signal in 1914. He was 85 years old when he died in 1950.
Contents
Apgar's equipment
Apgar fitted the electrical element of a headphone to a home-made recording head he attached to an Edison cylinder phonograph. This Rube Goldberg machine allowed him to record Morse code radio signals picked up by his receiver on wax cylinders. He made at least a dozen such recordings before 1915. In that era there were few radio stations to record, so most recordings made by Apgar are relatively pedestrian. He mostly recorded Morse code news bulletins from WHB in Manhattan.
Significance of the recordings
Apgar's original wax cylinders are lost, but some samples of his recordings survive. These still exist in yet another aircheck. Apgar made an appearance on station WJZ in New York City in 1934. Airchecks of this broadcast are owned by the Antique Wireless Association, and a tape copy is in the Library of Congress.
But on three cylinders Apgar managed to record some strange Morse code. Some of these led to the discovery of high-speed coded messages being transmitted by German spies through the Telefunken wireless station at Sayville, Long Island. This was critical information relating to the United States's entry into World War I. Prior to this, it was not possible to record messages for decoding.
Other accomplishments
Apgar later worked for the Marconi Company. While there he invented an ampliphone circuit which amplified even the smallest noises so as to make them easier to record. He also invented the paper cone loudspeaker which is used in most radios now.