Geodetic land survey leveling requires that correction of the instrument be done during the surveying process. This correction for sun, wind and air temperature is required to ensure accuracy of the leveling readings.

The thermistor is a dual sensor, aspirated digital thermometer which displays the real air temperature. Mounted on the tripod, it has sensors to be located 0.3 m and 1.3m above ground level. Each sensor has a precision fan which blows air over a thermocouple. Using a Fluke dual input digital thermometer, both sensors display the actual air temperature at the survey location.

The full explanation for the use and purpose of this instrument can be found on page 3-50, in the NOAA NOS NGS 3 "Geodetic Leveling" published by the National Geodetic Survey, Rockville, Maryland August 1981, Reprinted June 2001.

Web Link to NOAA NGS 3 Geodetic Leveling manuaL

To find more about the mission of the National Geodetic Survey branch of the National Oceanic and Atmospheric Administration, click here.

The case is constructed of heavy gauge welded aluminum, as are the two sensors. Aluminum clamps attach the main case and sensors to your tripod using wing nuts.

The two, precision fans in each ‘T’ sensor are powered from the lower compartment, containing a standard lithium cellphone battery power bank that is recharged by a USB port on the bottom of the instrument, which is covered with a moisture-proof cap- no need to open the thermistor case to recharge the battery.

The battery pack provides over 7 hours of continuous run-time for fan operation.

A heavy duty, waterproof toggle switch is located on the control panel to turn fans on.

An analog voltmeter displays the battery voltage of 5 volts D.C. to power the (2) fans in the sensors.

Using a dual input Fluke model 54II digital thermometer which has infrared data transfer, the temperature readings can be recorded in spreadsheet format on a laptop or personal computer by way of the USB port on the bottom of the instrument. A data collection application such as FlukeView is used to obtain the data. Please contact us for more information

With over 40 years of experience in the electronics industry, repairing and maintaining a diverse variety of equipment. Possessing an FCC General Radio Telephone license, as well as a low voltage electrical license, we can repair a wide range of equipment. As well as repair or fabricate signal or RF cables. Please contact us for your needs.