To see how this point changes with the depth of your dish, you can use the Focus of Parabola demonstration from Humboldt State University, in which you can increase or decrease the curvature of a ...

The symmetry of the parabola is created because each x value ... by the bowl and reflected from its steel surface into the focus box mounted on top of the central tower.

Schematic diagram of a parabolic reflector. Incoming sound is directed to the microphone placed at the focus of the parabola-shaped reflector. The property of the parabolic shape to reflect all sound ...