• Country
• United States of America (USA)

• Manufacturer / Brand
• General Radio Company; Cambridge (MA)

• Year
• 1925

• Category
• Radio module pre 1926 (not a part, not a key)

• Radiomuseum.org ID
• 202993

• • alternative name: GenRad

Click on the schematic thumbnail to request the schematic as a free document.

• Main principle
• RF-Circuit or wave trap (separate, can also be an antenna with amp.)

• Wave bands
• Broadcast only (MW).

• Power type and voltage
• No Power needed

• Loudspeaker
• - - No sound reproduction output.

• Material
• Various materials

• from Radiomuseum.org
• Model: Filter 247 - General Radio Company;

• Dimensions (WHD)
• 8 x 6 x 4 inch / 203 x 152 x 102 mm

• Notes
• Condenser in metal can, coil body made of Bakelite. The Variable Condenser is marked "Wavemeter". Type 247-W Filter to tune out Interference from unwanted stations. The wavelength is given as 150 to 500 metres, the max. capecity of the variable is 500 µµF.
  Not to be confused with the almost similar Type 274-W, wich covers a range of 200 to 600 metres.

• Price in first year of sale
• 10.00 $

• Mentioned in
• Radio News (January 1925 (p. 1318); February 1925 ( p. 1508))

• Author
• Model page created by Konrad Birkner † 12.08.2014. See "Data change" for further contributors.

• Other Models

• Here you find 241 models, 212 with images and 131 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from General Radio Company; Cambridge (MA)