Broadcasting-Satellite Coverage-Geometrical Considerations

Engineering studies of broadcasting-satellite utilization require the determination of such items as the coverage patterns on the surface of the earth ("footprints") of satellite spot beams, including the elevation and direction at which the satellite is seen, or, for interference study purposes, the determination of the antenna off-axis angle of interfering signals or, perhaps, the day and hour of solar noise increase ("sun-transit"). Simple formulas, based on a circular earth and geostationary orbit, provide approximate answers sufficient for the broadcast engineer. A number of such formulas in, it is believed, their simplest form, are given in the article with respect to the above subjects.