Lewis E. Vogler and James A. Hoffmeyer

Abstract: This report describes a new and unique approach for modeling either narrowband or wideband high frequency (HF) channels. Although narrowband models of the HF channel have existed for many years, they are applicable to only a limited set of actual propagation conditions. The need for an HF channel model that is valid for both narrow and wide bandwidths over a more extensive range of propagation conditions provided the motivation for the research documented in this report. The report describes the development of a channel transfer function for the HF channel that accurately models a wide variety of propagation conditions and can be used for the evaluation of wideband HF systems. The first part of this modeling effort has been to develop a model that represents the median channel conditions. Good agreement has been found between the model and wideband propagation measurements taken during relatively stable conditions. The report provides comparisons between ionograms generated by the model and measured wideband ionograms that have been reported in the literature. Encouraging results have also been found in comparing model outputs with measured time–history plots.

Keywords: spread spectrum; HF propagation; HF channel models; wideband communications; channel transfer function; wideband HF; over-the-horizon radar (OTHR)

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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