⭕ The Burndept IV Receiver plus the mark III Tuner are British pre-broadcast (pre-BBC) radio units of great rarity.
Mr Witt Burnham entered the wireless business in 1918 and sold crystal and valve receivers for home use from 1920. His wireless factory was located in Deptford, London, and the firm was given the trade name Burndept being a composite of owner and location names. Because of his early experience and expertise Burnham was appointed a director on the board of the BBC at its formation. Subsequently, the Burndept Wireless Ltd acquired such a reputation for quality and craftsmanship that the company became known as the Rolls Royce of British Wireless.
The radio consists of two units, a tuner and a receiver. The tuner is fitted with two variable condensers, a vernier two leaf condenser for fine tuning and an arrangement of three plug-in coils, two of which have adjustable coupling to the stationary one. The coupling is controlled by geared drives, presumably one for tuning (P) and the other for reaction (R). A two position switch on the front panel can select Standby or Tune. Terminals for aerial and earth are provided together with four terminals for connection to the main receiver.


The receiver is a four valve set with filament current rheostats for all valves and three two position switches to select on-off for Amplifier, L.F.1 and L.F.2. These facilities are provided to minimise battery drain if the extra stages of amplification are not required. A fourth switch selects either phones or loud speaker. A multi-tap sliding selector is used for reactance tuning between the two extreme taps of long and short waves.Terminals on the panel connect to the tuner and to L.T., H.T.1 and H.T.2 battery supplies. Terminals are also provided for either 120 ohm or 4000 ohm headphones. During the early days of radio, low rather than high resistance headphones from telegraph applications were readily available hence this facility. The four shorted terminals at the bottom of the panel are, according to the Burndept brochure, available for use with a printer or microphone relay presumably to receive telegraph signals. With fifteen control functions to play with in the process of tuning to a station, such early radios must have required unusual expertise and considerable patience from the owner!