Abstract: A method and installation for ground illumination by means of electromagnetic radiation generated by an aerial simulator coupled to the ground and for calculation of the dielectric constant and conductivity of the ground from said radiation are described. Radiation is transmitted in form of an electromagnetic pulse having predetermined characteristics from an aerial simulator of the horn type, the characteristics of the pulse are sensed at a point in the illuminated area and the dielectric constant and the conductivity of the ground are calculated from the detected values. The apparatus constituting the simulator comprises at least two conductive layers e.g. of conductive wires, united on one side to form the horn, and ending up on the opposite side at the ground where they are extended by a buried structure and on that side where they are united, in a connector to provide connection with pulse generating and measurement means.

Abstract: In the transmitter, a reference signal, produced by a voltage-controlled oscillator whose frequency is controlled by the battery voltage, is applied together with the signal to be transmitted to the transmission light emitting diode. In the receiver, the signal received is applied to a high-pass filter delivering the useful signal and to a low-pass filter reforming the reference signal. The same is compared with a predetermined voltage and the error signal is used for polarizing the reception diode and thereby maintaining constant the overall gain of the transmission channel. The output of the filter is also applied to a device controlling the voltage of the battery by measuring the frequency of the signal applied thereto.