The influence of receiver cross-modulation on attainable HF radar dynamic range

The performance of an HF radar system should ideally be limited by environmental factors as opposed to instrumental limitations. In this study the influence of one such limitation, receiver cross-modulation, is quantitatively assessed. An expression is derived for the attainable dynamic range, relating it to the receiver's linearity and the signal environment in which it is required to operate. In common with cross-modulation experienced in other receiving systems, the dynamic range is independent of the strength of the desired signal. In the context of HF radar this means that should the system performance be limited by cross-modulation, any increase in signal and clutter levels achieved through increased radiated power will be accompanied by a corresponding increased noise floor. The system would remain internally noise-limited, and any potential increase in sensitivity would not be realized.