On the use of remote sensing data in the estimation of ground conductivity

Ground wave propagation is characteristic of lower frequency bands, as LF (30¿300 kHz) and MF (300¿3000 kHz), and allows the radio coverage of extremely large areas from a single high-power transmitter. The use of these bands has gained interest in the recent years with the definition of digital broadcasting standards, in particular DRM (Digital Radio Mondiale) and IBOC (In-Band On-Channel), able to provide one or several high-quality audio services and complementary data services using the RF (Radio Frequency) channels currently employed for analog AM (Amplitude Modulation) broadcasting. Having in mind that the bandwidth of these channels is typically of 9¿10 kHz, it is clear that these new systems are extremely efficient in the use of the spectrum with a minimum infrastructure. The planning of these systems requires the characterization of ground conductivity, as it determines the attenuation of the ground wave. In this paper, a research work carried out in Mexico is described. Its objective is the investigation of the use of remote sensing data and techniques to improve the estimation of ground conductivity, in areas where no measurements are available or can be made.