RANGE-HEIGHT INDICATOR (RHI)

replacement of components, assemblies, or sub-assemblies, or (3) repair of certain units, assemblies or sub-assemblies designated as “shipboard repairable.” It may then require “turn in” of depot repairable assemblies or sub-assemblies through prescribed supply procedures. All replaceable modules, assemblies or printed circuit boards with a replacement value of $500 or more (except the CRT and high-voltage power supplies) are designed and constructed to be repairable by component replacement at the depot maintenance level. RANGE-HEIGHT INDICATOR (RHI) The range-height indicator (RHI) scopes used with height-finding radars obtain and display altitude information. The RHI is a two-dimensional presentation showing target range and altitude. An example of a RHI presentation is shown in figure 2-15. The sweep of a RHI starts in the lower left side of the scope and moves across the scope to the right at an angle that is the same as the angle of transmission of the height-finding radar. The line of sight to the horizon is indicated by the bottom horizontal line. The point Figure 2-15.—RHI presentation. directly overhead in the sky (the zenith) is straight up the left side of the scope. Targets are displayed as vertical blips. Vertical range markers are provided to estimate target range. The operator determines altitude by adjust- ing the moveable height line to the point where it bisects the center of the target blip. Target height is then read directly from altitude dials (counters). 2-23