submodes—automatic  search,  manual  search,  lock on,  automatic  track,  and  breakaway.  These  submodes parallel  the  general  submodes  found  in  actual weapons  control  systems. The trainer has no standby mode as such. (The purpose  of  a  standby  mode  is  to  apply  filament voltages   for   initial   warm-up   before   selecting   an operating  mode.)  Most  radar  sets  include  an automatic   time-out   (time-delay)   circuit,   which prevents  application  of  power  to  the  high-voltage sections  prior  to  the  necessary  warm-up  period. Search Mode Search  operation  for  airborne  and  ground  targets is provided with ranges of 0 to 6,000 yards and 0 to 12,000 yards. In this mode the antenna automatically scans  the  horizon,  rotating  in  a  clockwise  direction  at 6 RPM. Manual control of the antenna in this mode provides manual tracking of detected targets. There are  some  minor  differences  in  the  methods  of  manual control;   however,   they   are   of   little   consequence. Range  marks  are  selectable  in  1,000-,  2,000-,  or 3,000-yard  increments.  In  the  basic  search  mode,  the B-scope, which is also included in the indicator unit, is  deactivated. Fire Control Mode When  the  fire  control  mode  is  selected,  the  target simulator  provides  a  three-dimensional  target  (target with range, azimuth, and elevation information). In t h e    f i r e    c o n t r o l    m o d e ,    t h e r e    a r e    f i ve submodes—automatic  search,  manual  search,  lock on,   automatic   track,   and   breakaway.   The   five submodes  permit  the  simulated  target  to  be  detected initially,  manually  tracked  and  acquired,  and  tracked automatically  until  minimum  range  is  reached.  At this time, a breakaway signal in the form of a large X is  displayed  on  the  B-scope  indicator,  warning  the operator to break away from the target. In an actual weapons radar, the breakaway X also means that the aircraft is too close to the target to allow time for an air-to-air missile to properly track the target. Minimum range in fire control operation is 3,500 yards. Three  ranges  are  provided  for  target information  while  operating  in  the  fire  control mode-0  to  10,000,  0  to  40,000,  and  0  to  80,000 yards. During   this   mode   of   operation,   target information  is  displayed  on  both  the  PPI  and  B-scope of  the  indicator  display  unit.  The  B-scan  display  uses a dual-gun arrangement (to be discussed later), which provides  steering  information  in  addition  to  the normal plot display. Bomb Director Mode Operation in the bomb director mode covers the same   ranges   provided   in   the   fire   control   mode. Aiming information is displayed on the PPI display. Switching  circuits,  which  are  energized  at  the  time  of mode selection, cause the presentation to be altered to conform  to  typical  bomb  director  system  presenta- tions. The PPI display has a depressed-center sector scan at twice the scale of the fire control mode. The indicator  includes  controllable  range  and  azimuth marks (strobes), which act as cross hairs to facilitate aiming  (aim  point  tracking). SYSTEM  CONTROLS Through  the  manipulation  of the basic controls, the   operator   has   available   all   of   the   previously mentioned  modes  of  operation.  The  controls  of  the trainer  are  decentralized  to  simplify  construction  and operation,  but  these  controls  can  be  grouped  into  five major  categories  according  to  their  function.  The  five major control functions are as follows: 1. 2. 3. 4. 5. Power switch Mode switch Receiver gain control Antenna  control  (hand  control) Auxiliary   controls Power Switch The  power  switch  is  the  system’s  off-standby- operate switch. The off position, of course, removes all power from the system. The standby position, as previously  described,  would  apply  filament  power and  keep  alive  voltage  to  the  TR  tubes.  For  purposes of training, the 11D13A has a power switch for each of the major units antenna transmitter, and so forth). This allows for operation of each of the units or any selected  combination  of  units  for  training.  During  the discussion throughout this chapter, the appropriate control will be noted, along with its function and its relationship  to  one  of  the  four  major  function controls,  if  necessary. 3-10