From: A new portable ELF Schumann resonance receiver: design and detailed analysis of the antenna and the analog front-end
Mode
\( \overline{f}\;\left(\mathrm{Hz}\right) \)
σ f (Hz)
1
7.70
0.46
2
14.43
0.59
3
20.74
4
26.57
0.84
5
33.23
0.77
6
40.01
1.27