Radio [Crystal]
Maker and role
Brandes, Manufacturer
See full details
Object detail
Accession number
1994.5
Maker
Production period
Description
Crystal Radio.
Home-built crystal radio set. Consists of a double-coil variable tuner, Germanium crystal detector, and single earphone. The earphone is ex-military / Airforce. The radio is mounted on a wooden base with brass wingnuts to connect the earphones, antenna, and earth cables. On the back of the earphone, "Brandes / Superior / BBC / Pat's Pending / Matched Tone / TRADE MARK / Made in England" is impressed into the metal casing.
Home-built crystal radio set. Consists of a double-coil variable tuner, Germanium crystal detector, and single earphone. The earphone is ex-military / Airforce. The radio is mounted on a wooden base with brass wingnuts to connect the earphones, antenna, and earth cables. On the back of the earphone, "Brandes / Superior / BBC / Pat's Pending / Matched Tone / TRADE MARK / Made in England" is impressed into the metal casing.
Brief History
Crystal radios are the simplest form of radio receiving technology. By utilising the energy of the incoming radio waves no battery or additional power source is required to make the radio work. This type of radio is named for its use of a mineral crystal detector. A mineral such as Galena or Germanium is employed due to its semiconducting properties. Incoming radio waves induce an alternating current in the radio’s aerial. When this current passes through the crystal detector the current is rectified to a direct current. This in turn vibrates the earphone diaphragm to reproduce the transmitted sound based on the modulating amplitude of the incoming signal.
This particular radio is a simple home-built set using an early 1920s design, though it appears to have been made more recently. It includes a variometer constructed of two interacting spider coils. The orientation of these coils can be altered to tune the aerial’s resonant frequency and thus receive different stations. The crystal detector is of the cat-whisker type with a Germanium crystal. The unit is listened to via a single earphone that was salvaged from an ex-military aircraft.
This particular radio is a simple home-built set using an early 1920s design, though it appears to have been made more recently. It includes a variometer constructed of two interacting spider coils. The orientation of these coils can be altered to tune the aerial’s resonant frequency and thus receive different stations. The crystal detector is of the cat-whisker type with a Germanium crystal. The unit is listened to via a single earphone that was salvaged from an ex-military aircraft.
Marks
Brandes / Superior / BBC / Pat's Pending / Matched Tone / TRADE MARK / Made in England Impressed
Media/Materials
Credit Line
Brandes. Radio [Crystal], 1994.5. The Museum of Transport and Technology (MOTAT).
On display?
On display
Public comments
Be the first to comment on this object record.