AM broadcast antennas with elevated radial ground systems

Results are presented of computer modeling studies indicating that an elevated vertical monopole antenna with four elevated horizontal radials produces more ground-wave field strength than does a conventional ground-mounted monopole with 120 buried radials. For the analysis, the length of the radials and the height of the monopole were set equal to 0.25 of the free-space wavelength, and the frequency of operation was fixed at 1.0 MHz. Three different sets of ground constants were used, simulating averaging, very good, and very bad soil electrical parameters in accordance with the Numerical Electrical Code (NEC-GS)