Responder

United Wireless Telegraph Co. Responder was a rebadged American Deforest Spade Detector. The Deforest Spade Detector was also known as the responder, which was also known as an electrolytic detector, was developed by Lee de Forest in the early 1900s under his new company American Deforest.. American Deforest lasted until 1906 when in December, they defaulted on a $500,000 bond issue and the stock became worthless by 1907.

Abraham White then formed the United Wireless Telegraph Company in 1907. All of the assets of American De Forest were transferred to United Wireless including leftover responders. The first product of the newly formed company was the United Wireless Type "A" Receiver. The UWT Type "A" receiver consisted of the previous American Deforest Company's Deforest Syntonizer and the Deforest Responder. (Spade detector) This was the same set offered to the United States Navy circa 1905.

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Elenco delle radio e altri apparecchi della United Wireless Telegraph Co.; New York City, New York