The radio-frequency environment has an obvious and direct influence on the performance of electronic systems that depend upon the transfer of energy through space for their operation. Examples of such systems include radio communications, radio navigation, radar, and commercial AM, FM, and television broadcast systems. Less obvious, but nonetheless significant, is the influence the radio-frequency environment can have on electronic systems that ostensibly do not depend on the transfer of energy through space, for example, the degradation caused by electromagnetic fields generated by citizens band radios, radars, lightning, power lines, and electrostatic discharges on the performance of computers, process control equipments, automotive elec­ tronics and biomedical instrumentation. The beneficial and deleterious effects of man-made and naturally occurring electromagnetic fields on biological systems, including human beings, although little understood at present, may have more important long-term consequences than upon in the operation of equipment. As the radio-frequency environment evolves with the progression of the electronic age, the necessity to monitor, measure, and characterize it assumes greater importance. The purpose of this book is to provide, in a single self­ contained volume, the necessary background and methodology needed to execute a survey of the RF environment. We have included representative data on natural and man-made ambients in a variety of settings, wave propagation fundamentals, instrumentation descriptions, survey procedures, and data analysis techniques. Much experimental effort has been expended during this century to es­ tablish an adequate body of knowledge on the radio-frequency environment.