A new portable ELF Schumann resonance receiver: design and detailed analysis of the antenna and the analog front-end

Abstract

Schumann resonance oscillation detection is a complex procedure which requires customized and high-quality measurement systems. The primary objective of this work was to design and implement a stand-alone, portable, and low-cost receiver able to measure as much Schumann resonance harmonics as possible. Design, as well as detailed analysis of the efficient induction coil magnetic antenna and the low-noise amplifying-filtering chain, is presented. The detection system includes two coils back to back, resulting in a total coil length of 60 cm. The filtering and amplification chain exhibits an experimentally measured total passband gain equal to 112 dB at 10 Hz and as low as 2.88 nV/√Hz equivalent input noise. In order to validate the new portable ELF Schumann resonance detection and monitoring system, we took measurements at various spots "relatively" free from man-made electromagnetic pollution. Results have shown very clear Schumann resonance peaks for the first six modes with 10-min acquisition time.

Design and Implementation of a Test Fixture for ELF Schumann Resonance Magnetic Antenna Receiver and Magnetic Permeability Measurements

“…After several updates and tuning ups, the SR system was installed near the Doliana village in the Ioannina prefecture, Northwestern Greece. The ETA Lab's SR magnetic antenna receiver started measuring on the 19 January 2016 till now with concurrent recordings and measures up to six SR modes [30,38]. Recent discontinuities in the SR spectra of the detection station have shown a possible interconnection between lithospheric seismic activity and the atmospheric electromagnetic ELF background [16,17].…”

“…In February 2019, ETA Lab's SR data were made available to the scientific community through the MIT SuperCloud for the multi-station inversion calculation for global lightning activity. ETA Lab's ELF detector consists of the magnetic antenna and the signal conditioning chain [30] as well as the data acquisition (DAQ) chain [34]. The entire test fixture consists of the coil, the signal generator, and the oscilloscope with the extremely low frequency (ELF) detector to be calibrated.…”

“…The ELF receiver is a customized lab-made device that consists of the magnetic antenna, the amplifying filtering (signal conditioning), and data acquisition (DAQ) chains. A block diagram of signal conditioning and DAQ is depicted in Figure 6a, while the magnetic antenna [30,34] is depicted in Figure 2 Figure 6b. On top of the amplifying and filtering chain is located in the data acquisition chain.…”

“…There have been many studies evaluating diurnal or daily SR parameter variations in correlation mainly with several physical phenomena [27,28]. On the other hand, there is a lack of detail existing in the literature concerning the design and implementation of the electronic subsystems that are used for SR detection as well as the test fixtures and calibration methodologies [29,30]. Only a few studies have focused on the electronics of the system, for which remains vital to have reliable measurements and accurate SR detection [30][31][32][33][34].…”

“…On the other hand, there is a lack of detail existing in the literature concerning the design and implementation of the electronic subsystems that are used for SR detection as well as the test fixtures and calibration methodologies [29,30]. Only a few studies have focused on the electronics of the system, for which remains vital to have reliable measurements and accurate SR detection [30][31][32][33][34]. We present, to the best of our knowledge and for the first time, the design and implementation of a detailed test fixture for the calibrations of ELF SR magnetic antenna receivers.…”