Radiosonde
notes: label: Description
content: The National Bureau of Standards, which transferred this radiosonde to the Smithsonian in 1950, identified it as the first experimental radiosonde developed by H. Diamond, W. S. Hinman, Jr., and F.W. Dunmore at the Bureau and first used on 25 December 1936. A mark on the frame indicates that it was made by Friez & Sons of Baltimore. The unmarked balsawood box contains a transmitter (three vacuum tubes), a barometric switch (aneroid), and temperature (sulphuric acid resistor) and humidity (hair hygrometer) measuring elements. On the outside are two photo tubes.
label: Description
content: In 1936, the U.S. Navy asked the National Bureau of Standards to develop a radiosonde for the Navy to use. The NBS gave the project to Harry Diamond (1900-1948), who had previously worked on radio navigation and invented a blind landing system for airplanes. In 1937, Diamond, along with Francis Dunmore and Wilbur Hinmann, Jr., created a radiosonde that employed audio-frequency subcarrier modulation with the help of a resistance-capacity relaxation oscillator. This radiosonde could measure temperature and humidity at higher altitudes than conventional radiosondes at the time due to the use of electric sensors.
label: Location
content: Currently not on view
setName: label: See more items in
content: Medicine and Science: Physical Sciences
creditLine: label: Credit Line
content: National Bureau of Standards
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.313528
label: catalog number
content: 313528
label: accession number
content: 188571
objectType: label: Object Name
content: Radiosonde
physicalDescription: label: Measurements
content: overall: 8 3/4 in x 7 3/4 in x 6 1/4 in; 22.225 cm x 19.685 cm x 15.875 cm
label: Measurements
content: overall: 8 19/32 in x 8 in x 5 1/2 in; 21.844 cm x 20.32 cm x 13.97 cm