HF antenna radiation patterns over real terrain

In October 1987 advantage was taken of modern technology to put theories to the test by arranging for Swedtel to measure the radiation patterns of some of the Rampisham antennas by helicopter. Simultaneously the BBC made measurements of ground currents in front of some of the antennas to confirm the first part of the theory. The BBC also took the opportunity of measuring the variation of field strength at a height of 10 m along circumferential roads to see what correlation with the helicopter-measured horizontal radiation patterns could be obtained.<>