Portaphone radio receiver from Lowell & Dunmore case
date: label: date made
content: 1921
name: label: maker
content: National Bureau of Standards
notes: label: Description (Brief)
content: Marked: "Portafone / R1926". In the U.S. Patent Office, Lowell and Dunmore Exhibit No. 57. Believed to be the second Portaphone receiver. Unit is a six-tube tuned radio frequency receiver employing 215A "peanut" tubes. Case is actually a leather suitcase with a diaphragm-driven speaker horn and a coil antenna mounted in the top lid. Two 1.5 volt dry cells are strapped into the bottom of the case to provide filament voltages. An external plate battery was apparently used. The loudspeaker horn opens through an aperture in the cover of the leather case. This portable self-contained receiver was constructed by P.D. Lowell & F.W. Dunmore before the middle of 1921, and was demonstrated to visitors at the Bureau of Standards Radio Laboratory by Richard S. Ould, an electrical engineer who testified as a witness in the patent office Interference proceedings. An earlier model of the "portafone" was demonstrated before Alexander Graham Bell in May of 1921, and received radiotelephone broadcasts form station NSF in Anacostia. Reference: In the U.S. Patent Office" "Record and Testimony on Behalf of Lowell and Dunmore" (1928), page 503.
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.321931
label: catalog number
content: 321931
label: accession number
content: 245709
objectType: label: Object Name
content: Receiver
label: Object Name
content: radio receiver
label: Other Terms
content: Receiver; Radio; Portable
physicalDescription: label: Measurements
content: overall: 7 1/4 in x 18 1/2 in x 10 1/4 in; 18.415 cm x 46.99 cm x 26.035 cm