| 摘要 |
A plurality of explosive report devices (9) are spread out over a vineyard. An observer standing at a central radio transmitter station (7) with transmitter antennae (8) is able to observe the whole vineyard with the aid of binoculars. If a flock of starlings now approaches one of the, for example, eighteen explosive report devices (9) set up on the vineyard, and threatens to land there, the observer then presses one of eighteen switch pads in a switch box, which switch pad triggers the wireless radio signal, at whose frequency the electrical apparatus of the relevant explosive report device responds. Since the explosive report device has two sound tubes, it is possible to trigger a double explosive report without any difficulty, and at the same time the optimum time intervals can be chosen and adjusted. The essential point here is that the explosive report sounds at all times occur only in the immediate vicinity of a landing flock of starlings in order to drive the flock away. If the flock then attempts to land again at another position, the observer then activates the pad in his switch box which causes the explosive report device located at that position to emit an explosive report. <IMAGE>
|
