Modeling ground-wave propagation at MF band in hilly environments through FDTD method and interaction with GIS

This paper shows the calculation of electric field levels at MF band (medium frequency: 300 kHz–3 MHz) at different distances from the transmitter in environments where there are: (a) conductivity changes of the soil and (b) altitude variations. To assess the influence of these factors, a 2D tool named MF-FDTD (MF finite-difference time-domain) is implemented and it is calibrated and validated with the Millington method for flat land, and the FEM-PE (Finite Element Method-Parabolic Equation) for the inclusion of typified mountains. Then, this tool is also applied to real environments where certain AM (Amplitude Modulation) transmitters are located, selecting several profiles via a Geographic Information System. In our case, oscillations up to 10 dB have been obtained when comparing the results of irregular versus flat terrains with frequencies around 1 MHz. Part of the computation has been made using the Lusitania supercomputer, parallelizing tasks on multiple cores.