TY JOUR TI Development and testing of a portable "noise-meter" for areal magnetic noise survey KW Magneticobservatory KW magnetic data KW ground-based monitoring JO Russian Journal of Earth Sciences AU Kudin, D.V. AU Uchaikin, E.O. AU Gvozdarev, A.Y. AU Kudryavtsev, N.G. AU Krasnoperov, R.I. AU Szollosy, J.. AU Hegymegi, L.. PY 2020 IS 20 PB Geophysical Center of the Russian Academy of Sciences