• Country
• United States of America (USA)

• Manufacturer / Brand
• National Company; Cambridge & Malden (MA)

• Year
• 1938 ??

• Category
• Miscellaneous (Other, Various) - see notes

• Radiomuseum.org ID
• 86507

• • alternative name: National Toy Co.
  • Brand: Thrillbox

• Number of Tubes
• 1

• Valves / Tubes
• 80

• Power type and voltage
• Alternating Current supply (AC) / 115 Volt

• Loudspeaker
• Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 8 inch = 20.3 cm

• Material
• Metal case

• from Radiomuseum.org
• Model: Relay Rack HRO-SPC - National Company; Cambridge &

• Shape
• Rack

• Dimensions (WHD)
• 0 x 16 x 0 inch / 0 x 406 x 0 mm

• Notes
• Relay Rack unit matching the HRO series receivers, consisting of a coil rack for storing 5 HRO plug-in coils, an 8 inch dyn. speaker with an impedance matching transformer and a power supply for HRO(5897 character).
  Grey or black finish.
  Price in 1938 less tube.

• Price in first year of sale
• 90.00 $

• Source of data
• Communications Receivers

• Author
• Model page created by Martin Bösch. See "Data change" for further contributors.

• Other Models

• Here you find 445 models, 284 with images and 189 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from National Company; Cambridge & Malden (MA)