De Forest radio coil antennas
date: label: date made
content: 1924
name: label: maker
content: De Forest Radio Telephone & Telegraph Co.
notes: label: Description (Brief)
content: Marked: "De Forest Coil / Antenna / Pat. 2-17-03 / 10-11-04 / 12-15-05 / 4-22-06 / Other Patents Pending". This antenna is a plug-in unit for use with De Forest D-17 and D-12 Radiophone receivers. A switch is provided on the center of the loop that can be turned to make contact with six switch points and thus cut out six turns from the antenna. This enabled the antenna to tune 222 to 400 meters. For reception of 400 to 600 meter signals, the switch is rotated in the opposite direction. Turning the loop varies directivity pattern and thus the signal strength. Reference: Instruction book for De Forest D-12 Reflex Radiophone, 1924. Clark Collection, SRM 45-887A.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Franklin Wingard
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.321416.01
label: catalog number
content: 321416.01
label: accession number
content: 241556
objectType: label: Object Name
content: antenna
physicalDescription: label: Measurements
content: overall: 34 in x 27 in x 1 1/4 in; 86.36 cm x 68.58 cm x 3.175 cm