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Height finder

PRW-17 „Odd Group”
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Figure 1: PRW-17 „Odd Group”

Height finder

A height-finder is an older one ground-based type of 2-dimensional radar that measures the elevation angle and estimates the altitude of a target. The antenna pattern of a height-finder radar is a fan beam, quite narrow in azimuth but still much narrower in the elevation angle. The entire antenna of the altitude finder radar is moved mechanically up and down, in a nodding movement, which led to it also being called nodding radar.

The display type is of range-height indicator (RHI) using a sectoral scope with a polar coordinate system.

Height finders usually work in conjunction with an air surveillance radar using a rotating antenna. They get a target assignment, rotate with a handwheel manually its antenna in the desired direction and measures the elevation angle of this one target. Sometimes, the height-finder can also rotate synchronously with the surveillance radar and contribute to the image on the plan position indicator (PPI) by covering a specific height angle. Its echo signals are additionally displayed on the PPI-scope of the surveillance radar if the rotation between the two radar sets is synchronized.

With the introduction of 3D radars, these altitude height-finders have lost their importance.

Overview of height-finders.

Picture gallery of height-finder radar

Figure 2: Rack with the scopes of the height-finder PRW-13, top PPI-scope, bottom RHI-scope