Wrong answer

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.

Incorrect answers caused by reflection on an earth obstacle

Wrong answers are disturbing phenomena in a secondary radar , in which by reflection of electromagnetic waves from obstacles, the responses from transponders are displayed in a wrong direction and in a wrong distance.

This cause (reflective obstacle) can be localized by carefully observing the wrong answer. The apparent direction of the false answer β ₂ is equal to the direction of the reflecting obstacle. The difference between the apparent distance and the correct distance of the responding transponder is approximately the distance of the obstacle from the antenna.

These obstacles can often be changed in their properties by minor structural changes, so that incorrect answers no longer arise. For example, a chain link fence around the radar may be a cause of the wrong answers. If this fence is inclined by about 5 to 10 ° towards the radar, i.e. no longer built exactly vertically, then the reflections are also inclined towards the earth's surface and their intensity is reduced to such an extent that incorrect answers are no longer generated.