MF AM asymmetric vertical-dipole-antenna measurements

A medium-frequency AM transmitting vertical dipole for a 50 kW broadcast station was constructed, during May and June, 1994, at Buenos Aires, Argentina. This kind of vertical dipole operates without the classic, 120-wire, buried artificial ground plane. In order to analyze its behavior, extensive measurements of the near and far fields were carried out. A comparison to standard monopoles gave a better understanding of the performance and efficiency parameters. The nocturnal service area was determined by measurements, in order to observe the antenna's high-angle radiation, and to compare it with the theoretical radiation pattern. Comparison with the previous monopole antenna confirmed that substantial improvements were obtained with this new installation, both antennas being of similar height. The measurements showed an improved coverage of both diurnal and nocturnal service areas, estimated to be four times the previous service areas.