0402
   MEDIUM-RANGE DISTANCE METER  
EDM InstrumentsNext instrumentPrevious instrument

  Surveying Instrument Collection 

Maker

AGA, Sweden

Model

Geodimeter 14

Serial Number

14075

Dimensions

Length 220 mm, Width 190 mm, Height 87 mm (excluding handle)

Image

AGA Geodimeter 14

Description

This Geodimeter 14 is a compact and lightweight electro-optical distance measuring instrument intended for distances up to 10 km. It can be mounted on the telescope of most types of theodolites.

The measuring is made by means of infrared invisible light (IR-GaAs light emitting diode) with an effective light wavelength of 0.91 micrometres. To make the target easy to find, the instrument is directed with the aid of an audio-signal and a control instrument with pointer deflection. There is also a mode selector switch with three positions. When maximum accuracy is wanted, a measurement is first made with the switch in position 1 (Ph 1) and then in position 2 (Ph 2), whereafter the mean of the two results is calculated. The expected accuracy when using this type of measurement is (5 to 30 mm + 3 ppm). The third position (Auto) is used when the signal conditions are good and when it is important that the measurement can be done quickly. The accuracy of auto measurement is about (5 mm + 10 ppm). The measuring time per distance could be close to 15 s in 'Auto' mode and about 40 seconds per phase when using the 'Phase' mode.

The distance meter is equipped with a control knob with which the instrument can be adjusted for the greatest possible accuracy for existing measuring conditions. In addition, the atmospheric correction can be determined (based on measured temperature and pressure) with the aid of a correction scale and the correction factor is dialled in on the instrument, so that the display shows the corrected measuring value.

The maximum effective range of the distance meter using one prism, 3 prisms and 16 prisms is 4 km, 6 km and 10 km respectively, during good atmospheric conditions. The diameter of the objective aperture is 60 mm and the shortest measuring distance is 0.2 m. A 6 V battery is required to operate the instrument and its power consumption is approximately 20 W.

History & comments

The Geodimeter (acronym for geodetic distance meter) was the invention of the Swedish Physicist Dr. Erik Bergstrand who designed and applied it to the measurement of the speed of light over known distances in 1947. His original device weighed more than 100 kilograms and was the very first EDM instrument ever made (see 0411 for first commercial Geodimeter).

Conservation

Tough plastic case

Condition

The battery housing is slightly corroded.

Remarks
  • Weight of instrument is 2.5 kg
  • Type Number: 571113156
  • Catalogued by T. Ko
  • Updated by F. Pall

Dates

Manufactured in 1970 (approx). Catalogued in 2000.

[ Back to Contents ]