page_title: Radar display
section_title: Beta Scan Scope
hierarchical_section_title: Radar display / Beta Scan Scope
caption_attribution_description: SRA James Calkins, an air traffic controller with the 1974th Communications Group of the Air Force Communications Command (AFCC), is reflected in the precision approach radar scope as he directs an aircraft.Location: SCOTT AIR FORCE BASE, ILLINOIS (IL) UNITED STATES OF AMERICA (USA)
context_page_description: A radar display is an electronic device to present radar data to the operator. The radar system transmits pulses or continuous waves of electromagnetic radiation, a small portion of which backscatter off targets and return to the radar system. The receiver converts all received electromagnetic radiation into a continuous electronic analog signal of varying voltage that can be converted then to a screen display.
  Modern systems typically use some sort of raster scan display to produce a map-like image. Early in radar development, however, numerous circumstances made such displays difficult to produce. People ultimately developed several different display types.
context_section_description: The specialist Beta Scan Scope was used for precision approach radar systems. It displays two lines on the same display, the upper one (typically) displaying the vertical approach (the glideslope), and the lower one the horizontal approach. A marker indicates the desired touchdown point on the runway, and often the lines are angled towards the middle of the screen to indicate this location. A single aircraft's "blip" is also displayed, superimposed over both lines, the signals being generated from separate antennas. Deviation from the centerline of the approach can be seen and easily relayed to the pilot.
  In the image, the upper portion of the display shows the vertical situation, and the lower portion the horizontal. In the vertical, the two diagonal lines show the desired glideslope (upper) and minimum altitude approach (lower). The aircraft began its approach below the glideslope and captured it just before landing. The proper landing point is shown by the horizontal line at the left end. The lower display shows the aircraft starting to the left of the approach line and then being guided toward it.
caption: A Beta Scan display.
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