Radio waves used in weather radar systems are in the  SHF range such as 5.44 GHz or 9.375 GHz. They are  transmitted forward of the aircraft from a directional antenna  usually located behind a non-metallic nose cone. Pulses of  approximately 1 micro-second in length are transmitted.  A duplexer in the radar transceiver switches the antenna  to receive for about 2,500 micro seconds after a pulse is  transmitted to receive and process any returns. This cycle  repeats and the receiver circuitry builds a two dimensional  image of precipitation for display. Gain adjustments control  the range of the radar. A control panel facilitates this and  other adjustments.  [Figure 11-143]  Severe turbulence, wind shear, and hail are of major concern  to the pilot. While hail provides a return on weather radar,  wind shear and turbulence must be interpreted from the  movement of any precipitation that is detected. An alert is  annunciated if this condition occurs on a weather radar system  so equipped. Dry air turbulence is not detectable. Ground  clutter must also be attenuated when the radar sweep includes  any terrain features. The control panel facilitates this.  Special precautions must be followed by the technician  during maintenance and operation of weather radar systems.  The radome covering the antenna must only be painted with  approved paint to allow the radio signals to pass unobstructed.  Many radomes also contain grounding strips to conduct  lightning strikes and static away from the dome.  When operating the radar, it is important to follow all  manufacturer instructions. Physical harm is possible from  the high energy radiation emitted, especially to the eyes and  testes. Do not look into the antenna of a transmitting radar.  Operation of the radar should not occur in hangars unless  special radio wave absorption material is used. Additionally,  operation of radar should not take place while the radar is  pointed toward a building or when refueling takes place.  Radar units should be maintained and operated only by  qualified personnel. Lightning detection is a second reliable means for identifying  potentially dangerous weather. Lightning gives off its own  electromagnetic signal. The azimuth of a lightning strike can  be calculated by a receiver using a loop type antenna such as  that used in ADF.  [Figure 11-144]  Some lightning detectors  make use of the ADF antenna. The range of the lightning  strike is closely associated with its intensity. Intense strikes  are plotted as being close to the aircraft. Stormscope is a proprietary name often associated with  lightning detectors. There are others that work in a similar  manner. A dedicated display plots the location of each strike  within a 200 mile range with a small mark on the screen. As  11-64 Figure  11-142. A dedicated weather radar display (top) and a  multifunctional navigation display with weather radar overlay  (bottom).  Figure 11-141.  The decision height, DH200, in the lower right  corner of this EADI display uses the radar altimeter as the source  of altitude information.  10 10 10 10 20 20 DH200 -4 80 110 60 4 45 6 SPD LIM VI INOP KGRN KBU C KBJ C L89 308 KHEF KCOS KCEN NORTH UP KFTC H8 2 KCLN KGHR KLAR KLVL LAR HCT H82 KDEN KFTR W  GP H 25 V SIG / AIR MAP NRST WPT AUX NEXRAD AGE: 5min RAIN MIX SNOW L I  G  H  T H  E  A  V  Y 30NM $_{5}$338 $_{1}$1652 200 46 13.7 2300 23.0 NAV1 117.95 115.40 NAV2 108.00 117.95 123.750 119.925 COM1 135.975 120.050 COM2 GS 123kts DIS 53.2NM ETE 25:58 ESA 16800 ENGINE ECHO TOP CLD TOP LTNG CELL MOV METAR NEXRAD LEGEND MORE WX MAP - NAVIGATION MAP