Forecasting Television Service Fields

The propagation of VHF and UHF television signals over a spherical, irregular surface such as the earth is examined theoretically and experimentally and the principal factors evaluated. The principal factors are found to be frequency, meteorology, terrain and vegetation. It is shown that meteorology, terrain and vegetation vary a significant amount geographically and that local values should be used in forecasting local service fields. The principal factors are included in a new empirical method suggested for forecasting the service fields of television stations. The signal forecast by the new method is compared with field-measured signals with good results.