The 2 needles provide both directional and pseudo range indication.
The directional side is indicated by the point at which the needles intersect. If this intersection is LEFT of the centreline of the instrument then the aircraft is displaced to the right. and vice versa.
Pseudo range is provided by the distance the the intersection point is from the base of the instrument. The closer the intersection point is to the base of the instrument the closer to the runway threshold you are. This pseudo range is based on signal strength. There is an auto change in receiver sensitivity during the approach. In the real instrument this sensitivity change was selected manually.
A Lorenz installation needs to be placed by the map builder for this unit to work.
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