Abstract: This invention relates to a wide aperture radio frequency data acquisition system which collects coherent samples from multiple points in a defined plane at the surface of the ground. The information collected can be processed with suitable algorithms to extract the bearing, frequency, and power spectra of the arriving radio frequency wavefront.This system consists of an antenna system; a multi-channel receiver system incorporating mixers, filters, amplifiers, analog to digital converters, digital down converters; a digital signal processor; and a computer. The electrically short, active antennas with frequency independent response are connected to the multiple channel receiving system, one channel per antenna receiving the signal. The receiver uses two frequency conversion oscillators for coarse but accurate frequency synthesis to convert the received signal's frequency. Then, the signal is converted to a digital signal.