The report describes the systems used to record wideband 12 Hz - 300 Hz extremely low frequency ELF electromagnetic noise in a number of geographic locations. The first section centers on the analog recording system employed in Florida. Simply stated, analog tapes were recorded and later converted to digital tapes for further processing. Section II describes the NAVCOM system which employed on site digital recording. The final section describes the calibration procedures used to relate the digitalized data to absolute electromagnetic field levels. A distinctive feature of both systems is the care taken to preserve the wide dynamic range of the ELF noise while reducing the amount of man-made interference recorded. Results of analyzing the recorded noise data to optimize communications system performance in this frequency band are described in companion reports.