Calculating Disc, Electronic Evaluation Slide Rule, Felsenthal FDN-9

Description
To check the accuracy of radar measurements, the U.S. Navy used a device called an echo box. This small plastic instrument allowed one to correct echo box dial readings according to the temperature and the form of radar used. A tag received with the object indicates that it was sold by Felsenthal as the FDN-9.
Reference:
U.S. Department of the Army, Test Set TS-172A/UP, Technical Manual 11-1262, 1991, p. 2-1 through 3-2.
Location
Currently not on view
date made
1969
maker
Felsenthal Instrument Co.
Physical Description
plastic (overall material)
metal (overall material)
Measurements
overall: .1 cm x 14.6 cm x 15.2 cm; 1/32 in x 5 3/4 in x 5 31/32 in
ID Number
1977.1141.32
catalog number
336416
accession number
1977.1141
Credit Line
Gift of Ben Wharton Rau and Margery Felsenthal Rau
subject
Mathematics
Radar
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Military
Data Source
National Museum of American History, Kenneth E. Behring Center

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