BeachComber detects CW signals in an input signal that is hundreds of megahertz in bandwidth. Using power spectrum techniques, it provides sub-band tuned snippets of the detected CW signal to a post-processing system for characterization. In order to optimize the sub-band tuning and post-processing, this system applies a set of heuristics to each signal detected and some associated historical information. These rules determine when sub-band tuned snippets of the input signal data are captured for post-processing. Also, the system provides a panoramic environment display that graphically pictures a time versus frequency plot of the signals detected.