text: FM 7-100.1________________________________________________________________________________
  battle line, realizing that such placement increases their vulnerability to enemy
  direct fire systems. When necessary, tactical- or even operational-level air de-
  fense systems may deploy beyond the battle line, out into the disruption zone.
  9-136. As OPFOR units maneuver, the air defense umbrella also moves when
  necessary, in order to prevent maneuver units from becoming exposed to enemy
  ground-attack aircraft and armed helicopters. In a fluid, fast-developing
  situation, textbook efficiency may not be possible. While the OPFOR strives
  to maintain continuous area coverage, temporary gaps might appear in the air
  defense umbrella, both in surveillance and in weapons coverage. Commanders
  must be flexible and prepared to use standard and nonstandard solutions to
  prevent gaps in air defense coverage from developing during combat. The
  objective is to deny enemy aviation the ability to interfere with ground
  maneuver units. Air defense forces can accomplish this either by destroying
  enemy aircraft, by forcing them expend their munitions beyond effective
  range, or by diverting the aircraft before reaching their targets.
  30,000
  25,000
  20,000 OPERATIONAL-
  STRATEGIC- LEVEL SAMs STRATEGIC-
  LEVEL SAMs LEVEL SAMs
  10,000
  Height in
  Meters
  TACTICAL-
  5,000
  LEVEL
  SAMs
  3,000
  2,000
  1,000
  250 200 150 100 50 0 50 100 150 200 250 km
  Range in Kilometers
  Figure 9-2. Air Defense Coverage (Example)
  9-137. Figure 9-2 illustrates the vertical and horizontal coverage typically
  provided by OPFOR air defense systems at the tactical, operational, and
  strategic (national) levels. The example altitudes and ranges are illustrative
  of a principle. The actual systems and their capabilities can vary. Although
  not shown in this example, all SAM systems have a minimum range and a
  minimum altitude. Of course, the range beyond the battle line or limit of
  responsibility of supported forces depends on the situation and where the air
  defense systems deploy within the supported unit’s AOR.