• Country
• United States of America (USA)

• Manufacturer / Brand
• Radio Foundation Inc.; New York City, New York

• Year
• 1925 ??

• Category
• Radio part (not a module) 

• Radiomuseum.org ID
• 147229

• 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
• Various materials

• from Radiomuseum.org
• Model: R.F.I. Doughnut Toroid Coils - Radio Foundation Inc.; New

• Shape
• Miscellaneous shapes - described under notes.

• Notes
• Radio Foundation R.F.I. "Doughnut" Toroid Coils, Tuned Radio Frequency Transformers;
  Set of three Doughnut shaped RF coils, green colored wire, manufactured by Radio Foundation Inc., 25 West Broadway, New York City.

• Author
• Model page created by a member from A. See "Data change" for further contributors.

• Other Models

• Here you find 3 models, 3 with images and 0 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Radio Foundation Inc.; New York City, New York