• Country
• United States of America (USA)

• Manufacturer / Brand
• Kellogg Switchboard & Supply Co.; Chicago (IL)

• Year
• 1923

• Category
• Radio part (not a module) 

• Radiomuseum.org ID
• 137124

• • Brand: Wavemaster

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

• Wave bands
• Wave Bands given in the notes.

• Power type and voltage
• No Power needed

• Loudspeaker
• - - No sound reproduction output.

• Material
• Bakelite case

• from Radiomuseum.org
• Model: Variometer 501 - Kellogg Switchboard & Supply

• Price in first year of sale
• 8.00 $

• Source of data
• - - Manufacturers Literature

• Mentioned in
• QST Sept.1923, p. 94

• Author
• Model page created by Otto Frosinn. See "Data change" for further contributors.

• Other Models

• Here you find 66 models, 25 with images and 17 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Kellogg Switchboard & Supply Co.; Chicago (IL)