User's Manual

Receiver model: WH2642
Sensor model: WH22B
Version 1.0 Page 34
Term
Definition
Relative Barometric Pressure.
Accuracy
Accuracy is defined as the ability of a measurement to match the actual
value of the quantity being measured.
Barometer
A barometer is an instrument used to measure atmospheric pressure.
Calibration
Calibration is a comparison between measurements – one of known
magnitude or correctness of one device (standard) and another
measurement made in as similar a way as possible with a second device
(instrument).
Dew Point
The dew point is the temperature at which a given parcel of humid air
must be cooled, at constant barometric pressure, for water vapor to
condense into water. The condensed water is called dew. The dew point
is a saturation temperature.
The dew point is associated with relative humidity. A high relative
humidity indicates that the dew point is closer to the current air
temperature. Relative humidity of 100% indicates the dew point is equal
to the current temperature and the air is maximally saturated with water.
When the dew point remains constant and temperature increases,
relative humidity will decrease.
HectoPascals (hPa)
Pressure units in SI (international system) units of measurement. Same
as millibars (1 hPa = 1 mbar)
Hygrometer
A hygrometer is a device that measures relative humidity. Relative
humidity is a term used to describe the amount or percentage of water
vapor that exists in air.
Inches of Mercury (inHg)
Pressure in Imperial units of measure.
1 inch of mercury = 33.86 millibars
Rain Gauge
A rain gauge is a device that measures liquid precipitation (rain), as
opposed to solid precipitation (snow gauge) over a set period of time.
All digital rain gauges are self emptying or self dumping (also referred
to as tipping rain gauge). The precision of the rain gauge is based on the
volume of rain per emptying cycle.
Range
Range is defined as the amount or extent a value can be measured.
Relative Barometric
Pressure
Measured barometric pressure relative to your location or ambient
conditions.
Resolution
Resolution is defined as the number of significant digits (decimal
places) to which a value is being reliably measured.
Thermometer
A thermometer is a device that measures temperature. Most digital
thermometers are resistive thermal devices (RTD). RTDs predict change
in temperature as a function of electrical resistance.
Wind Vane
A wind vane is a device that measures the direction of the wind. The
wind vane is usually combined with the anemometer. Wind direction is
the direction from which the wind is blowing.
6. Specifications
6.1 Wireless Specifications
 Line of sight wireless transmission (in open air): 300 feet, 100 feet under most conditions
 Update Rate: about one minute
 Frequency: 915 MHz