Laser Systems EDM (Ranger)

Description
The Ranger was the first of a series of laser based EDMs developed by Laser Systems & Electronics (LSE). Introduced in 1970, it cost $8,000, and had a "self contained digital computer" that made it "completely automatic and extremely fast." The Ranger had a range of from 1 meter to 6 km with an accuracy of ±5 mm +2 ppm. It weighed 32 lbs, and used a 12-volt power supply. This example belonged to a surveyor who was "always crazy about new gadgets." He bought it after seeing one at the American Congress of Surveying and Mapping meeting in 1970, and used it until 1973.
The impetus for making an EDM with automatic read-out came from Robin Hines, who had observed that the EDMs used by Tennessee Valley Authority surveyors were cumbersome, and the data had to be sent to headquarters for analysis. William Hollinshead, who designed the TVA computer, worked with the chip designers at Texas Instruments to learn the strengths and weaknesses of the computer chips available at that time. Another critical problem—generating the frequencies needed for the beam—was solved by using a temperature-controlled crystal oscillator. This example bears the marking, "Ranger LSE Laser Systems & Electronics Inc. Tullahoma, Tenn. Ser. No. 07B1008.”
There were two patents associated with the Ranger. One (#3,740,141), for "Timing and Measuring Methods and Means for Laser Distance Measurement," was granted in June 1973 to John H. DeWitt Jr. of Nashville, and assigned to LSE. John Shipp and Robin Hines had done the design work, but when they left the firm, their names were removed from the patent application; DeWitt was a member of the LSE board. The other (#3,778,159), for "Distance Measuring Apparatus and Method Utilizing Phase Comparison of Modulated Light Beams," was granted in December 1973 to Hines, Hollinshead, and Thomas O. Bolden, and assigned to LSE.
Ref: LSE, Price List. Ranger and Accessories (Oct. 1, 1970).
LSE, Laser Ranger Specifications.
LSE, Operating Instructions for Laser Ranger.
Location
Currently not on view
Object Name
EDM
maker
Laser Systems & Electronics
Measurements
overall: 19 in x 21 1/2 in x 17 in; 48.26 cm x 54.61 cm x 43.18 cm
place made
United States: Tennessee, Tullahoma
ID Number
1996.0199.01
accession number
1996.0199
catalog number
1996.0199.01
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center

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