Stone Vintage Radio Museum - Antique Radios, Wireless, Crystal Sets, Tubes, and Valves

The Marconi multiple tuner was used with the Marconi magnetic detector pictured elsewhere on this page. The magnetic detector needed something to tune in the frequency wanted. The multiple tuner was developed to do just that. Patented in 1907, C. S. Franklin of the Marconi Company was the one who developed it. The multiple tuner was produced for ship or shore installations in conjunction with the magnetic detector. The magnetic detector or “maggi” was first introduced in 1903. It was connected to the terminals, marked 'detector' on the multiple tuner. With the switch on the multiple tuner set at 'tune', the magnetic detector was in series with a condenser that was coupled inductively with another circuit called the intermediate circuit. This intermediate circuit was coupled with the antenna circuit. Each of these circuits was adjusted to the desired wavelength. Most Marconi instillations from 1907-1914 used the multiple tuner. It can be seen with the magnetic detector in many pictures of early shipboard radio rooms. The three round objects on the top of the tuner are high quality variable condensers. The parallel horizontal bars on the front are for tuning and the large knob on the front left is for varying inductance. By selecting the appropriate taps of the antenna inductance, variocouplers, and variable condensers, the set can cover 80-2600 meters. The Multiple tuners worked very well considering when they were developed. The tuner pictured here is serial number 35038 and was probably made somewhere between 1907 and 1909.

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