The performance of HF curtain antennas with irregular foregrounds

The VRP of HF curtain arrays has traditionally been estimated by regarding the ground as a horizontal, reflecting plane. This approach has been shown to be inadequate for arrays with irregular foregrounds. A new model has been developed that calculates the current density induced by the array at small, regular intervals in the foreground. The values of current density are used to establish a set of discrete current elements, whose sum at various angles in the far field is used to calculate the effect of the foreground on the VRP. The results of the model are compared with experimental results obtained from tests at a BBC transmitting site.<>