Abstract: The invention relates to a system for actuating signal transmitters that are arranged on aviation obstacles, which are obstacles for low-flying airplanes, and signal transmitters for optically warning the airplanes or the pilots thereof, having the following features: a) at least one large-area radar system which is designed to detect airplanes flying at very low altitudes and which is arranged at a location remote from the aviation obstacles, b) at least one computer device which is coupled to the large-area radar system so as to transmit signals and which is designed to evaluate the data provided by the large-area radar system, said data relating to detected airplanes, and to provide such data to other systems via a data connection, and c) at least one data connection between the computer device and multiple aviation obstacles and/or groups of aviation obstacles, wherein d) the computer device is designed to output activation signals for the signal transmitters of aviation obstacles which are being approach

Abstract: A beacon, especially for a wind turbine, comprising a support structure; at least two different LED units circumferentially mounted thereon and directed outwardly and alternating in a circumferential direction, with emitted light of first and second ones of the LED units differing with respect to their spectral compositions and being activatable separately from one another; and a linear lens disposed outwardly of the LED units, extending the circumferential direction, and serving to bundle light emitted from the LED units, with the linear lens being shared by all of the LED units.