A system includes a very low frequency (VLF) antenna connected to a circuit that has a high pass filter and a low pass filter. The circuit is configured for noise reduction and frequency localization of detected VLF signals. A receiver is configured to receive filtered VLF signals output by the circuit and to separate desired signals for processing. A display is configured to provide a user with visual feedback based at least in part on an even signature extracted by a digital signal processor (DSP).