Barbora Bezdekova¹, Frantisek Nemec¹, Jyrki Kalervo Manninen², George B Hospodarsky³, Ondrej Santolik⁴, William S Kurth³ and David Hartley⁵, (1)Charles University, Prague, 180, Czech Republic, (2)Sodankyla Geophysical Observatory, Sodankyla, Finland, (3)University of Iowa, Department of Physics and Astronomy, Iowa City, IA, United States, (4)IAP Prague, Praha 4, Czech Republic, (5)University of Iowa, Iowa City, IA, United States