Hewlett-Packard Model 3800B Distance Meter

The Hewlett-Packard Model 3800B distance meter was an electronic distance measurement instrument that used infrared light to measure distances of up to two miles. The instrument was designed to be lightweight and easy to set up. Introduced in 1969, the National Geodetic Survey quickly adopted the 3800B.

Hewlett-Packard Model 3800B Distance Meter

The cover shown on the bottom right is a calibration cap designed and built by the Instrument and Methodologies Branch of the National Geodetic Survey. Photos courtesy of Charlie Glover.

William Hewlett, one of the founders of Hewlett-Packard (HP), believed that his company's photo-diode technology could improve electronic distance measurement instruments and thus the HP Model 3800B distance meter series was introduced in 1969.

The HP 3800B weighed 17 pounds (plus a 13-pound power pack) and used gallium arsenide diode as a semiconductor. Running an electric current through the diode caused the emission of infrared light, which could then be directed to a reflector. The instrument worked by sending a light signal of known wavelength to a reflector. The wavelength of the returning signal was compared to the outgoing one, and the difference (called the "phase shift") was measured. Using multiple frequences of light, the instrument computed a distance based on the known lengths and measured phase shifts of returning light waves.

Having a range of about two miles, the HP 3800B was used by the National Geodetic Survey for all its medium-range duties in the 1970s. The HP 3800B was issued to triangulation parties for use in measuring between survey stations and their azimuth marks as well as for mark maintenance work. It was also used by Aeronautical Survey Program crews to collect data used to develop runway approach procedures and obstruction charts for U.S. airports.

  • Distance Measurement Instrument Shown: Hewlett-Packard Model 3800B Distance Meter
  • Location: Corbin, Virginia
  • Manufacture Date: 1969
  • Dates of Use: 1970s
  • Photo Date: 2006


Works Consulted

Burger, T. C., Tomlinson, R. W. (1975). Electronic Distance Measuring Instruments. Washington, DC: American Congress on Surveying and Mapping.

Smithsonian Virtual Surveying Instrument Collection. EDM (Helett-Packard 3800B) Retrieved June, 2006, from: http://americanhistory2.si.edu/collections/surveying/object.cfm?recordnumber=748833.


Related Web Sites

National Geodetic Survey