Some propagational aspects of frequency allocation and frequency sharing

The propagation phenomena of importance to the allocation and sharing of frequency bands are briefly summarized. Those aspects most significant for the various frequency bands are highlighted, illustrated, and referenced. Systems normally achieve their required grade of telecommunications service (service fields) by reliance upon standard modes of electromagnetic propagation. However, both standard modes (so-called) and anomalous modes of propagation must be considered when describing interference phenomena (interference fields). Further, these standard modes are described for any specific service as tending to be stable (relatively) and predictable. The anomalous modes, however, are described as involving some degree of uncertainty; they tend to be less stable and less predictable/anomalous, can involve different selections across the spectrum and with various services. Hence, for interference fields, the categorization is described herein as essentially by geometry. That is, interference situations are terrestrial Earth to space, or space to space propagational situations.