Lowell and Dunmore original Bureau of Standards AC-powered radio receiver
date: label: date made
content: 1922
name: label: associated person
content: Dubilier, William
label: maker
content: De Forest Radio Telephone & Telegraph Co.
label: maker
content: Dubilier Condenser Corp.
label: maker
content: Radio Instrument Co.
label: maker
content: Magnavox Company
notes: label: Description (Brief)
content: Unit is a 6 tube tuned radio frequency receiver designed to operate from a separate power supply. (Cat.#321,926). Specimen developed at Bureau of Standards in 1922 by P .D. Lowell and F. W. Dunmore as a very early application of the alternating current power supply to a radio receiver. The circuitry consists of three RF stages, a crystal detector and two audio stages. The crystal was used to help reduce the problem of 60 cycle hum as well as being employed as the detector. Two adjustable balancing resistances were utilized for the purpose of reducing hum caused by grid voltage variations. For better simplification, a C battery was employed for bias in the final audio stages. Tubes used are 201A type. A speaker horn mounted under the lid is essentially a headphone unit driving a flare-type horn. This receiver was also connected to a Magnavox loud speaker unit. The RF stages employ Radio Instrument Co. DX transformers with a range of 170-450 meters. Depending upon the RF coils employed, this unit could recieve 30-1500 kc, AM or spark, and CW signals with the use of an external heterodyne.
label: Description (Brief)
content: Marked: (1) Supreme Court of the U.S., Oct. Term 1935 Plaintiffs respondents Exhibit No. 19. (2) United State of America vs. Dubllier Condenser Corp. Plaintiffs Exhibit No. 67. (3) Patent Office Interferences-Lowell & Dunmore Exhibit no. 45. (for detailed tag data see acc. papers) (Plate marked: BS31249) (Components lit-see Acc. papers). Reference: U.S. Dept. of Commerce Scientific Paper No. 450, Oct. 2,1922. U.S. Patent 1455141, Radio Receiving Apparatus, Issued May 15,1923 to P.D.Lowell & F.W. Dunmore. Vol 1- 4th Circuit Court of Appeals Transcript, pages 119-120.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from John B. Brady, thru Mrs. John B. Brady
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.321925
label: catalog number
content: 321925
label: accession number
content: 245709
label: collector/donor number
content: 31249
label: collector/donor number
content: BS31249
objectType: label: Object Name
content: Receiver
label: Object Name
content: radio receiver
label: Other Terms
content: Receiver; Radio; Table
physicalDescription: label: Measurements
content: overall: 11 1/4 in x 15 in x 9 1/4 in; 28.575 cm x 38.1 cm x 23.495 cm