Capturing, extracting and storing narrowband IQ data for later processing enables timely and efficient analysis. As wideband capture of RF information includes noise and non-signal elements, the present invention detects, extracts and stores narrowband IQ signals for later assessment. By transforming a high-volume data stream to a collection of smaller narrowband signals with greatly reduced storage and on-board processing requirements the present invention facilitates the capability to analyze signals of interest in an otherwise denied environment.