9ABD

On this site, during the night hours of January 27, 1917, eighteen year old Willis Porter Corwin received and re-transmitted three Morse Code messages, which became the first successful one-way transcontinental relay of formal message traffic in the history of American radio. Conducted as an experiment by pioneer amateur radio operators, these messages, which were originated by citizens in Los Angeles, were sent to a station in Denver which relayed them to young Corwin in Jefferson City. He in turn passed them on to a station in Albany, New York, from whence they were forwarded to their destinations in Hartford, Connecticut. He repeated the experiment in more dramatic fashion ten days later, conducting the first successful two-way transcontinental relay whereby a message was started from the east coast, relayed to the west coast, and an answer received back on the east coast within a span of eighty minutes.

Willis Corwin, Jefferson City's first-known amateur wireless operator and recognized throughout the country by the call sign, 9ABD, constructed his spark-gap transmitter, power supply, and antenna entirely by hand. His radio shack was located in an enclosure at the base of a wooden tower supporting his Marconi-style antenna at the rear of his parents' residence here at 117 E. McCarty Street. The first man from Jefferson City to enlist in World War I, he served with the United States Naval Reserves as Chief Electrician (Radio) in France and as a wireless operator aboard the troop ship taking him to Europe. After the war, Corwin built and installed Jefferson City's first commercial AM broadcast station, WOS, in the dome of the State Capitol for the Missouri Department of Agriculture. He later helped construct radio station KSD in St. Louis for the St. Louis Post-Dispatch, where he did pioneering work on wire-photo transmission years before it became a reality.

Willis Porter Corwin died at the age of sixty on January 27, 1959, exactly forty-two years to the day after the historic transcontinental record, and is buried in the Jefferson City National Cemetery, nine blocks east of here.

This plaque dedicated on January 27, 2007 by the Mid-Mo Amateur Radio Club to mark the 90th anniversary of the first wireless transcontinental relay of formal message traffic.

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