Charles Apgar

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Charles Apgar, a New Jersey amateur radio operator, is known for making the earliest surviving recordings of a radio signal in 1914.

[edit] 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.

[edit] Significance of the recordings

Apgar's original wax cylinders are long since 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. These airchecks of airchecks 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 II. Previous to this, it was not possible to record messages for decoding.

[edit] Other accomplishments

Charles later worked for the Marconi Corporation. 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 we use in most radios now.