No. 3975 (Model 4)

The Atwater Kent No. 3975 (Model 4) Receiving Set was one of the earliest and rarest in the legendary "breadboard" line, introduced on December 23rd, 1922. This set was a three-tube Tuned Radio Frequency (TRF) circuit, comprised of a detector and two stages of audio amplification, and it featured four main components on the board: a variocoupler, a variometer, detector and the amplifier island. Unlike the Model 1, 2, and 3, the Model 4 was engineered to be sold as a complete system that was regenerative from the factory. Board dimensions are 24-1/2" x 8-1/2".

Image Courtesy of Grant Kornberg, Technogallerie

Image Courtesy of Grant Kornberg, Technogallerie

Image Courtesy of Grant Kornberg, Technogallerie

Image Courtesy of Grant Kornberg, Technogallerie

Reinhard Brothers Style Model 4 (See Homebrews & NonFactory Sets)

Image Courtesy of Grant Kornberg, Technogallerie

Image Courtesy of Grant Kornberg, Technogallerie

Image Courtesy of Grant Kornberg, Technogallerie

Image Courtesy of Grant Kornberg, Technogallerie