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The following might be caused by antenna shadowing:
  • A
    A weather radar failing to show a distant turbulent cloud due to the signals being blocked by a nearer cloud.
  • B
    Poor radio reception of a VOR ident signal while the aircraft is making an orbit (360° medium-level turn).
  • C
    An aircraft appearing as two distinct Indications on a radar controller's display.
  • D
    Blocking of a VOR transmission caused by buildings close to the antenna.

Antenna shadowing

Shadowing by parts of an aircraft (such as a wing) may prevent signals from being received if the antenna is not sited properly.

To minimize the adverse effects of antenna shading, it is important to place antennas on aircraft in such locations where least shading can be expected in any normal flight attitude. Antennas used for reception of ground-based facilities should be on the underside of the aircraft while GPS antennas should be on the top.

During 360º medium-level turn, the effect of the wing shadowing the aircraft antenna should be considered.

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