Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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EDM  (Benchmark) - click to enlarge

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EDM (Benchmark)

Catalogue number:
1996.0187.01

Inscriptions:
"Alpha Electronics Denver, Colorado seriel no 03001 Made in U.S.A." and "BENCHMARK"

Dimensions:
10 inches high, 12.5 inches wide, 8 inches deep

Discussion:
This is a prototype of a short-range infrared edm with a remote control keyboard that allowed surveyors "to rapidly enter data (for atmospheric corrections, horizontal reduction, etc.) and make distance shots without touching the critical alignment of theodolite and target." It used a gallium-arsenide light-emitting diode, weighed under 4 lbs, and had a range of 1 mile with an accuracy of 0.02 feet ±2 ppm. The structural components were made of "space age materials" (a G.E. plastic known as Menlon), and were apparently relatively inexpensive to produce. It was made in 1980.

This instrument came from John I. Shipp, a physicist who had played a major role in the design of the Ranger and Beetle edms. It is the first unit manufactured by Alpha Electronics, a firm that Shipp and others established in the mid 1970s. Shipp withdrew from Alpha Electronics in mid-1980, and established Benchmark in Tullahoma, Tennessee. The edm, now known as the Surveyor, was on the market by the summer of 1981. Surveyor I-X had a range of 1 km and cost $2,995. Surveyor II-X had a range of 2 km and cost $3,495. Several thousand of these instruments were eventually sold in the United States. John Shipp and Charlie Rose received a design patent (#268,910) for the Surveyor on May 10, 1983, and assigned it to Benchmark.

Ref: Benchmark brochures for Surveyor I. Remote Control Electronic Distance Meter, and Surveyor I with Telecommand.

Advertisement in P.O.B. (June-July 1981): 43.

Further Information:

EDM

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