Analytical expressions for the electromagnetic field have been used to compute electric and magnetic field strengths in the near-vicinity of dipole and monopole transmitting antennas. In particular the fields about a half-wave length dipole are mapped to illustrate the magnitude and wide variation of field intensity which occurs near the feed point, along the axis of the dipole, and about the tip of the radiating arms. These results are analyzed in terms of evaluating potential radiofrequency hazards which may exist extremely near dipole like broadcast antennas and the aspect of close proximity exposure of maintenance personnel is discussed. The field expressions are used to determine the extent of near-field gain compression which occurs at distances close to the antenna and this is compared with measured field intensity data taken for a halfwave dipole using a short, nonperturbing field probe. The results for a single dipole are used to model a vertically stacked array of dipole radiating elements used to simulate a typical FM broadcast transmitting antenna. Expected field intensities are then determined for positions close to such radiating structures to assess the potential of biologically significant fields existing about present day FM broadcast installations. It is found that near-field gain compression can be significant for typically encountered building exposures wherein main beam illumination is possible.

"June 1978." "ORP-EAD-78-4." Cover title. Includes bibliographical references (pages 36-39).