Abstract: A device for shredding objects includes a feed tray for the reception of objects to be shredded, a roller shredder with at least one powered roller and a further working means in the form of a roller or a comb-shaped counterpart, between which a working gap is formed, in order to shred objects from the feed tray and convey them through the working gap, and a pushing element which can be moved in the feed tray and by means of which the objects to be shredded can be conveyed to the roller shredder. The feed tray can be closed on an upside by a removable cover and an interior space of the feed tray is connected to a suction device for producing a negative pressure.

Abstract: An arrangement for measuring the liquid level in a tank. The arrangement has a microwave transmitting/receiving device and a waveguide that extends into the tank for guiding a coupled-in microwave. The waveguide has clear and constant wave propagation characteristics for a wave with the operating frequency.

Abstract: For an aircraft radar arrangement, particularly helicopters, a first frequency is provided at a maximum of atmospheric attenuation and a second frequency near the first frequency in a region of less atmospheric attenuation, preferably at 60 GHz and 50 GHz. The first frequency serves to provide obstacle warnings, the second to provide for moving target detection and navigation. The mm wave components of the arrangement can substantially be used for both frequencies so that significant savings in weight, space and costs result.