• Country
• United States of America (USA)

• Manufacturer / Brand
• Wireless Specialty Apparatus Co.; Boston (MA)

• Year
• 1919 ?

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

• Radiomuseum.org ID
• 198649

• Wave bands
• Long Wave and/or Very Low Frequency (VLF).

• Power type and voltage
• No Power needed

• Loudspeaker
• - - No sound reproduction output.

• Material
• Wooden case

• from Radiomuseum.org
• Model: Long Wave Loading Unit Type IP 503 - Wireless Specialty Apparatus

• Shape
• Tablemodel, Box - most often with Lid (NOT slant panel).

• Dimensions (WHD)
• 18 x 9.25 x 9.25 inch / 457 x 235 x 235 mm

• Notes
• The IP 503 Long Wave Loading Unit was designed for use with the IP 500 and IP 501 radio receivers. When placed on top of either receiver, the binding posts on the IP503 line up with the loading coil terminals on the receivers. Short jumper straps were used to link them together. Later the !P 501A was designed so that it too could be used with the IP 503.Use of these coils extended the frequency range of the receivers to 19,000 meters, the longest wavelength of commercial stations in use.

• Net weight (2.2 lb = 1 kg)
• 9.6 kg / 21 lb 2.3 oz (21.145 lb)

• Mentioned in
• Radiola, the golden Age of RCA (Page 122)

• Author
• Model page created by Alan Larsen. See "Data change" for further contributors.

• Other Models

• Here you find 68 models, 66 with images and 1 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Wireless Specialty Apparatus Co.; Boston (MA)