Figure 2-8.AN/GMQ-29 readout panel.
located in the weather office. The sensor group is
usually located near the runway. First, lets look at the
ML-400/UMQ-5 wind transmitter
ML-643/GMQ-29 dew-point sensor
ML-641/GMQ-29 air temperature sensor
ML-642/GMQ-29 pressure sensor
The display group consists of a light emitting diode
(LED) readout panel, a slide-mount drawer that
contains the controller and processing electronics and
switches, and the RO-447/GMQ-29 analog recorder for
wind speed, wind direction, and rainfall.
ML-588/GMQ-14 tipping-bucket rain gauge
The readout panel is shown in figure 2-8. It has
digital LED readouts for time, air temperature, dew-
point temperature, maximum and minimum
temperatures, wind direction and speed, pressure, and
rainfall. The panel is also equipped with a digital
The AN/GMQ-29 weather station is shown in
figure 2-9. The sensor group inputs are connected to the
display group through a data transmission line. This
equipment is maintained by base ground electronics
personnel. Only the temperature sensors and rain gauge
are currently used with most GMQ-29 systems. First,
lets look at the air temperature and dew-point sensors,
and then discuss the rain gauge.
Dew-point and Air Temperature Sensors
Some of the LED readouts are not in operation.
Because of the pressure sensor systems age and
inaccuracy, this feature is no longer used. The wind
direction and wind speed display provides a 14- to 16-
second averaged wind speed; this 14- to 16-second
The ML-641/GMQ-29 air temperature sensor is
shown in figure 2-10.
The sensor consists of a
resistance element probe mounted in an enclosure. The
enclosure shields the sensor from solar radiation and
precipitation, yet allows a free flow of air.
update is not up to current meteorological standards.
The time display, which indicates coordinated universal
time (UTC), is not always accurate; therefore, a
supplemental clock for time reference may be used.
The air temperature, dew-point temperature, and
maximum- and minimum-temperature readouts,
provided in degrees Fahrenheit, are reliable and are
used as the primary source for these observation
readings. Switches in the controller drawer are used to
reset the maximum and minimum temperatures.
The accumulated precipitation readout, in inches,
tenths, and hundredths of an inch, is also reliable. The
precipitation readout is reset to zero by using the reset
switch in the front of the controller drawer.
The RO-447/GMQ-29 analog recorder has been
disconnected or turned off on most units. The RD-
108/UMQ-5 analog recorder is the primary equipment
used for evaluation of wind speed and direction. The
RD-108/UMQ-5 is discussed later in this chapter.
Now lets look at the AN/GMQ-29 sensor group.
The AN/GMQ-29 sensor group is located outside
the building, usually near the most active runway.
Several sensor groups may be used with a single display
group. The sensor group consists of the following units: