Simplified calculation of coverage area for MF AM broadcast stations

It is shown that the coverage area of medium- and high-frequency stations using ground-wave propagation beyond the horizon, especially MF AM stations, can be calculated by a simplified method. Recent field measurements have shown that the cumbersome FCC and CCIR calculations for estimating service area can be simplified to allow calculations with a PC, or even a programmable pocket calculator. The ground-wave electrical field intensity calculations are simplified by the introduction of a shadow or diffraction factor in the Norton planar earth expression. This factor permits the ground E field to be calculated well beyond the geometric and radio horizon, where E-field values are close to the atmospheric noise level. The approach permits engineers or technicians to calculate their own E=field curves for any frequency and any kind of soil.<>