TM 55-1510-219-10 degrees up or down from horizontal attitude of aircraft. 60°  switch Push   type   on/off   switch.      When activated.      reduces   antenna   scan from 120 to 60°. TRACK switches Momentary    action    type    switches. When  activated,  a  yellow  track  line extending    from    the    apex    of    the display    through    top    range    mark appears   and   moves   either   left   or right,     depending     on     the     switch pressed.  The track line position will be displayed in degrees in the upper left  corner  of  the  screen.    The  line will     disappear     approximately     15 seconds after the switch is released. It   will   then   automatically   return   to "0" degrees. HOLD switch Push   type   on/off   switch.      When activated,  the  last  image  presented before pressing the switch is displayed    and    held.        The    word HOLD  will  flash  on  and  off  in  the upper    left    corner    of    the    screen. Pressing the switch again will update    the    display    and    resume normal scan operation. Function switch Controls operation of the radar set. OFF Turns set off. STBY Places  set  in  standby  mode.    This position  also  initiates  a  90  second warmup delay when first turned on. TEST Displays   test   pattern   to   check   for proper   operation   of   the   set.      The transmitter   is   disabled   during   this mode. ON Places set in normal operation. MODE switches Momentary    action    type    switches. Pressing  and  holding  either  switch will   display   an   information   list   of operational data on the screen.  The data heading will be in blue, all data except    present    data    will    be    in yellow,   and   present   selected   data will    show    in    blue.        The    three weather  levels  will  be  displayed  in red,   yellow,   and   green.      If   WXA mode   has   been   selected,   the   red bar   will   flash   on   and   off.      If   the switch  is  released  and  immediately pressed again, the mode will in- crease   or   decrease   depending   on switch pressed.  When either top or bottom mode is reached, the opposite  switch  must  be  pressed  to further change the mode. NAV switch Interfaces  radar  indicator  with  INS navigational    information    to    show INS waypoint positions, superimposed on the weather display, relative to aircraft position. BRT control Used to adjust screen brightness. c. Normal Operation. WARNING Do  not  operate  the  weather  radar set while personnel or combustible  materials  are  within 18   feet   of   the   antenna   reflector When   the   weather   radar   set   is operating, high-power radio frequency  energy  is  emitted  from the  antenna  reflector,  which  can have harmful effects on the human body and can ignite combustible materials. CAUTION Do  not  operate  the  weather  radar set in a confined space where the nearest   metal   wall   is   50   feet   or less   from   the   antenna   reflector. Scanning such surfaces may damage receiver crystals. (1) Turn-on     procedure.          Function     switch TEST or ON, as required.  (Information will appear after time delay period has elapsed.) (2) Initial adjustments operating procedure. 1. BRT control As required. 2. MODE      switches   Press   and release as required. 3. RANGE   switches   Press   and release as required. 4. TILT control Move up or down to   observe   targets   above   or below aircraft level.  The echo display  will  change  in  shape and location only. 3-73