Frekuensi ultra rendah: Perbedaan antara revisi

'''Frekuensi ultra rendah''' (ULF) adalah sebutan [[International Telecommunication Union|ITU]]<ref name="ITU Nomenclature">{{Cite web |title=Rec. ITU-R V.431-7, Nomenclature of the frequency and wavelength bands used in telecommunications |url=http://www.itu.int/dms_pubrec/itu-r/rec/v/R-REC-V.431-7-200005-I!!PDF-E.pdf |url-status=dead |archive-url=https://web.archive.org/web/20131031020427/http://www.itu.int/dms_pubrec/itu-r/rec/v/R-REC-V.431-7-200005-I%21%21PDF-E.pdf |archive-date=31 October 2013 |access-date=20 February 2013 |publisher=ITU}}</ref> untuk rentang frekuensi gelombang elektromagnetik antara 300 [[Hertz]] dan 3&nbsp;kHz, sesuai dengan panjang gelombang antara 1.000 hingga 100&nbsp;km. Dalam ilmu [[magnetosfer]] dan [[seismologi]], definisi alternatif biasanya diberikan, termasuk rentang dari 1 mHz hingga 100&nbsp;Hz,<ref>V. A. Pilipenko, "ULF waves on the ground and in space", [[Journal of Atmospheric and Terrestrial Physics]], Volume 52, Issue 12, December 1990, pp. 1193–1209, {{ISSN|0021-9169}}, {{doi|10.1016/0021-9169(90)90087-4}}.</ref> 1 mHz hingga 1&nbsp;Hz,<ref>T. Bösinger and S. L. Shalimov, "On ULF Signatures of Lightning Discharges", [[Space Science Reviews]], Volume 137, Issue 1, pp. 521–532, June 2008, {{doi|10.1007/s11214-008-9333-4}}.</ref> dan 10 mHz hingga 10&nbsp;Hz.<ref>O. Molchanov, A. Schekotov, E. Fedorov, G. Belyaev, and E. Gordeev, "[http://www.nat-hazards-earth-syst-sci.net/3/203/2003/nhess-3-203-2003.pdf Preseismic ULF electromagnetic effect from observation at Kamchatka] {{Webarchive|url=https://web.archive.org/web/20200204182132/https://www.nat-hazards-earth-syst-sci.net/3/203/2003/nhess-3-203-2003.pdf |date=2020-02-04 }}", ''Natural Hazards and Earth System'' Sciences, Volume 3, pp. 203–209, 2003</ref>