0404
   SHORT-RANGE DISTANCE METER  
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  Surveying Instrument Collection 

Maker

Hewlett-Packard (USA)

Model

HP 3800B

Serial Number

1226A00368

Dimensions

Length 330mm, Width 260mm, Height 145mm

Image

HP 3800B Distance Meter

Description

This Hewlett-Packard HP 3800B short-range distance meter is an electro-optical measuring instrument capable of measuring distances up to 3 kilometres using three reflectors (in ideal conditions).

The distance meter itself is supported by a yoke which allows it to rotate either upwards or downwards about the horizontal axis, and it can also be removed from this yoke by unscrewing the holding screw. Similar to a theodolite, the yoke also features vertical and horizontal clamps and tangent screws for accurate pointing of the instrument.

The objective end of the distance meter features the 'transmitter' and 'receiver' lenses. The transmitter lens has a smaller diameter and is positioned inside the receiver lens. The sighting telescope, located on top of the instrument, is used to point the instrument at the reflector. The instrument is pointed at the reflector by sighting through the telescope and adjusting the horizontal and vertical tangent screws until the cross hairs intersect a point approximately 70mm above the reflector. The telescope features internal focusing, stadia cross hairs and 18x magnification. 

An external power unit can be attached to the instrument, which operates from an internal 12 volt rechargeable battery good for 8 hours of operation when fully charged. The precision of distance measurement is (3mm+0.00001D), where D represents the distance measured in kilometres.

When measuring long distances during poor atmospheric conditions, the measuring time of the distance meter can be as long as 2 minutes. The distance measurement is not fully automatic. The operator has to zero an ammeter at different frequencies.

History & comments

Instrument was purchased by the then School of Surveying in the early 1970's.

Conservation

In a hard plastic case

Condition

Good

Remarks
  • This instrument is one of the two HP 3800B's in the collection (see also 0405)
  • Weight of distance meter is 7.7 kg
  • Weight of external power unit is 6 kg
  • Catalogued by T. Ko
  • Updated by F. Pall

Dates

Manufactured in 1965 (approx). Catalogued in 2000

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