Field strength predictions using a computer and a terrain data base

The SERV computer program in which from stored topographical data, the ground profile along the radial from the transmitter to a chosen receiver location is reconstructed, and the path attenuation to be expected along this profile is evaluated, is presented. Each map is divided into 500 m squares, and each square is represented by a single height. The prediction method was tested on data from heavily built up areas at 168, 455 and 900 MHz. It is found that predictions are always optimistic by 35 to 42 dB. It is shown that the inclusion of a clutter factor produces calculations of signal levels very close to measured values.