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id="toc-Military" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Military"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Military</span> </div> </a> <ul id="toc-Military-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Experimental_and_amateur" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Experimental_and_amateur"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>Experimental and amateur</span> </div> </a> <ul id="toc-Experimental_and_amateur-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Meteorological_information_broadcasts" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Meteorological_information_broadcasts"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>Meteorological information broadcasts</span> </div> </a> <ul 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<span>Antennas</span> </div> </a> <button aria-controls="toc-Antennas-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Antennas subsection</span> </button> <ul id="toc-Antennas-sublist" class="vector-toc-list"> <li id="toc-Longwave_receiving_antennas" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Longwave_receiving_antennas"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Longwave receiving antennas</span> </div> </a> <ul id="toc-Longwave_receiving_antennas-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Antenna_heights" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Antenna_heights"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Antenna heights</span> </div> </a> <ul id="toc-Antenna_heights-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Directional_array_antennas" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Directional_array_antennas"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Directional array antennas</span> </div> </a> <ul id="toc-Directional_array_antennas-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Footnotes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Footnotes"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Footnotes</span> </div> </a> <ul id="toc-Footnotes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>External links</span> </div> </a> <ul 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Available in 27 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-27" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">27 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%AA%D8%B1%D8%AF%D8%AF_%D9%85%D9%86%D8%AE%D9%81%D8%B6" title="تردد منخفض – Arabic" lang="ar" hreflang="ar" data-title="تردد منخفض" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Baixa_freq%C3%BC%C3%A8ncia_(radiofreq%C3%BC%C3%A8ncia)" title="Baixa freqüència (radiofreqüència) – Catalan" lang="ca" hreflang="ca" data-title="Baixa freqüència (radiofreqüència)" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Dlouh%C3%A9_vlny" title="Dlouhé vlny – Czech" lang="cs" hreflang="cs" data-title="Dlouhé vlny" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Langb%C3%B8lger" title="Langbølger – Danish" lang="da" hreflang="da" data-title="Langbølger" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Langwelle" title="Langwelle – German" lang="de" hreflang="de" data-title="Langwelle" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Baja_frecuencia" title="Baja frecuencia – Spanish" lang="es" hreflang="es" data-title="Baja frecuencia" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Longondo" title="Longondo – Esperanto" lang="eo" hreflang="eo" data-title="Longondo" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%A8%D8%B3%D8%A7%D9%85%D8%AF_%D9%BE%D8%A7%DB%8C%DB%8C%D9%86" title="بسامد پایین – Persian" lang="fa" hreflang="fa" data-title="بسامد پایین" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Basse_fr%C3%A9quence" title="Basse fréquence – French" lang="fr" hreflang="fr" data-title="Basse fréquence" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%9E%A5%ED%8C%8C" title="장파 – Korean" lang="ko" hreflang="ko" data-title="장파" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%A8%E0%A4%BF%E0%A4%AE%E0%A5%8D%E0%A4%A8_%E0%A4%86%E0%A4%B5%E0%A5%83%E0%A4%A4%E0%A5%8D%E0%A4%A4%E0%A4%BF_(LF)" title="निम्न आवृत्ति (LF) – Hindi" lang="hi" hreflang="hi" data-title="निम्न आवृत्ति (LF)" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Frekuensi_rendah" title="Frekuensi rendah – Indonesian" lang="id" hreflang="id" data-title="Frekuensi rendah" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Low_frequency" title="Low frequency – Italian" lang="it" hreflang="it" data-title="Low frequency" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Laangwell" title="Laangwell – Luxembourgish" lang="lb" hreflang="lb" data-title="Laangwell" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Hossz%C3%BAhull%C3%A1m" title="Hosszúhullám – Hungarian" lang="hu" hreflang="hu" data-title="Hosszúhullám" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mg mw-list-item"><a href="https://mg.wikipedia.org/wiki/Onja_lava" title="Onja lava – Malagasy" lang="mg" hreflang="mg" data-title="Onja lava" data-language-autonym="Malagasy" data-language-local-name="Malagasy" class="interlanguage-link-target"><span>Malagasy</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Low_frequency" title="Low frequency – Dutch" lang="nl" hreflang="nl" data-title="Low frequency" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E9%95%B7%E6%B3%A2" title="長波 – Japanese" lang="ja" hreflang="ja" data-title="長波" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Fale_d%C5%82ugie" title="Fale długie – Polish" lang="pl" hreflang="pl" data-title="Fale długie" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Onda_longa" title="Onda longa – Portuguese" lang="pt" hreflang="pt" data-title="Onda longa" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Dlh%C3%A9_vlny" title="Dlhé vlny – Slovak" lang="sk" hreflang="sk" data-title="Dlhé vlny" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/LF_(taajuusalue)" title="LF (taajuusalue) – Finnish" lang="fi" hreflang="fi" data-title="LF (taajuusalue)" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/L%C3%A5g_frekvens" title="Låg frekvens – Swedish" lang="sv" hreflang="sv" data-title="Låg frekvens" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/D%C3%BC%C5%9F%C3%BCk_frekans" title="Düşük frekans – Turkish" lang="tr" hreflang="tr" data-title="Düşük frekans" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%94%D0%BE%D0%B2%D0%B3%D1%96_%D1%85%D0%B2%D0%B8%D0%BB%D1%96" title="Довгі хвилі – Ukrainian" lang="uk" hreflang="uk" data-title="Довгі хвилі" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Low_frequency" title="Low frequency – Venetian" lang="vec" hreflang="vec" data-title="Low frequency" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target"><span>Vèneto</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E4%BD%8E%E9%A0%BB" title="低頻 – Chinese" lang="zh" hreflang="zh" data-title="低頻" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q17156810#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit 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.hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"Low band" redirects here. For the musical group Low, see <a href="/wiki/Low_(band)" title="Low (band)">Low (band)</a>.</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox hproduct"><caption class="infobox-title fn" style="padding-bottom:0.2em;"><span class="fn">Low frequency</span></caption><tbody><tr><th scope="row" class="infobox-label" style="padding-top:0.15em;padding-right:1.0em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Frequency range</div></th><td class="infobox-data"><span class="nowrap">30–300 <a href="/wiki/KHz" class="mw-redirect" title="KHz">kHz</a></span></td></tr><tr><th scope="row" class="infobox-label" style="padding-top:0.15em;padding-right:1.0em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Wavelength range</div></th><td class="infobox-data"><span class="nowrap">10–1 <a href="/wiki/Metre" title="Metre">km</a></span></td></tr></tbody></table> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist 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screen{html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media print{body.ns-0 .mw-parser-output .sidebar{display:none!important}}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><table class="sidebar nomobile nowraplinks"><tbody><tr><th class="sidebar-title"><a href="/wiki/Radio_spectrum" title="Radio spectrum">Radio bands</a></th></tr><tr><th class="sidebar-heading" style="background:#ddddff;"> <a href="/wiki/ITU_radio_bands" class="mw-redirect" title="ITU radio bands">ITU </a></th></tr><tr><td class="sidebar-content" style="padding-top:0.2em; padding-bottom:0.6em;"> <table style="margin:0 auto;text-align:left;"><tbody><tr style="vertical-align:top"><td style="padding-right:1.0em;;"> <a href="/wiki/Extremely_low_frequency" title="Extremely low frequency">1 (ELF)</a></td><td style="padding-right:1.0em;;"> <a href="/wiki/Super_low_frequency" title="Super low frequency">2 (SLF)</a></td><td style="padding-right:1.0em;;"> <a href="/wiki/Ultra_low_frequency" title="Ultra low frequency">3 (ULF)</a></td><td style="padding-right:1.0em;;padding-right:0;"> <a href="/wiki/Very_low_frequency" title="Very low frequency">4 (VLF)</a></td></tr><tr style="vertical-align:top"><td style="padding-right:1.0em;;"> <a class="mw-selflink selflink">5 (LF)</a></td><td style="padding-right:1.0em;;"> <a href="/wiki/Medium_frequency" title="Medium frequency">6 (MF)</a></td><td style="padding-right:1.0em;;"> <a href="/wiki/High_frequency" title="High frequency">7 (HF)</a></td><td style="padding-right:1.0em;;padding-right:0;"> <a href="/wiki/Very_high_frequency" title="Very high frequency">8 (VHF)</a></td></tr><tr style="vertical-align:top"><td style="padding-right:1.0em;;"> <a href="/wiki/Ultra_high_frequency" title="Ultra high frequency">9 (UHF)</a></td><td style="padding-right:1.0em;;"> <a href="/wiki/Super_high_frequency" title="Super high frequency">10 (SHF)</a></td><td style="padding-right:1.0em;;"> <a href="/wiki/Extremely_high_frequency" title="Extremely high frequency">11 (EHF)</a></td><td style="padding-right:1.0em;;padding-right:0;"> <a href="/wiki/Terahertz_radiation" title="Terahertz radiation">12 (THF)</a></td></tr></tbody></table></td> </tr><tr><th class="sidebar-heading" style="background:#ddddff;"> <a href="/wiki/NATO_radio_bands" class="mw-redirect" title="NATO radio bands">EU / NATO / US ECM </a></th></tr><tr><td class="sidebar-content" style="padding-top:0.2em; padding-bottom:0.6em;"> <div class="hlist"> <ul><li><a href="/wiki/A_band_(NATO)" title="A band (NATO)">A</a></li> <li><a href="/wiki/B_band_(NATO)" title="B band (NATO)">B</a></li> <li><a href="/wiki/C_band_(NATO)" title="C band (NATO)">C</a></li> <li><a href="/wiki/D_band_(NATO)" title="D band (NATO)">D</a></li> <li><a href="/wiki/E_band_(NATO)" title="E band (NATO)">E</a></li> <li><a href="/wiki/F_band_(NATO)" title="F band (NATO)">F</a></li> <li><a href="/wiki/G_band_(NATO)" title="G band (NATO)">G</a></li> <li><a href="/wiki/H_band_(NATO)" title="H band (NATO)">H</a></li> <li><a href="/wiki/I_band_(NATO)" title="I band (NATO)">I</a></li> <li><a href="/wiki/J_band_(NATO)" title="J band (NATO)">J</a></li> <li><a href="/wiki/K_band_(NATO)" title="K band (NATO)">K</a></li> <li><a href="/wiki/L_band_(NATO)" title="L band (NATO)">L</a></li> <li><a href="/wiki/M_band_(NATO)" title="M band (NATO)">M</a></li> <li><a href="/wiki/N_band_(NATO)" title="N band (NATO)">N</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#ddddff;"> <a href="/wiki/Radio_spectrum#IEEE" title="Radio spectrum">IEEE </a></th></tr><tr><td class="sidebar-content" style="padding-top:0.2em; padding-bottom:0.6em;"> <div class="hlist"> <ul><li><a href="/wiki/High_frequency" title="High frequency">HF</a></li> <li><a href="/wiki/Very_high_frequency" title="Very high frequency">VHF</a></li> <li><a href="/wiki/Ultra_high_frequency" title="Ultra high frequency">UHF</a></li> <li><a href="/wiki/L_band" title="L band">L</a></li> <li><a href="/wiki/S_band" title="S band">S</a></li> <li><a href="/wiki/C_band_(IEEE)" title="C band (IEEE)">C</a></li> <li><a href="/wiki/X_band" title="X band">X</a></li> <li><a href="/wiki/Ku_band" title="Ku band">K<sub>u</sub></a></li> <li><a href="/wiki/K_band_(IEEE)" title="K band (IEEE)">K</a></li> <li><a href="/wiki/Ka_band" title="Ka band">K<sub>a</sub></a></li> <li><a href="/wiki/V_band" title="V band">V</a></li> <li><a href="/wiki/W_band" title="W band">W</a></li> <li><a href="/wiki/Extremely_high_frequency" title="Extremely high frequency">mm</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#ddddff;"> Other TV and radio</th></tr><tr><td class="sidebar-content" style="padding-top:0.2em; padding-bottom:0.6em;"> <div class="hlist"> <ul><li><a href="/wiki/Band_I" title="Band I">I</a></li> <li><a href="/wiki/Band_II" title="Band II">II</a></li> <li><a href="/wiki/Band_III" title="Band III">III</a></li> <li><a href="/wiki/Band_IV" title="Band IV">IV</a></li> <li><a href="/wiki/Band_V" title="Band V">V</a></li> <li><a href="/wiki/Band_VI" title="Band VI">VI</a></li></ul> </div></td> </tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Radio_bands_sidebar" title="Template:Radio bands sidebar"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Radio_bands_sidebar" title="Template talk:Radio bands sidebar"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Radio_bands_sidebar" title="Special:EditPage/Template:Radio bands sidebar"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p><b>Low frequency</b> (<b>LF</b>) is the <a href="/wiki/International_Telecommunication_Union" title="International Telecommunication Union">ITU</a> designation<sup id="cite_ref-ITU_Nomenclature_1-0" class="reference"><a href="#cite_note-ITU_Nomenclature-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> for <a href="/wiki/Radio_frequency" title="Radio frequency">radio frequencies</a> (RF) in the range of 30–300 <a href="/wiki/KHz" class="mw-redirect" title="KHz">kHz</a>. Since its wavelengths range from 10–1 <a href="/wiki/Kilometre" title="Kilometre">km</a>, respectively, it is also known as the <b>kilometre band</b> or <b>kilometre wave</b>s. </p><p>LF radio waves exhibit low signal <a href="/wiki/Attenuation" title="Attenuation">attenuation</a>, making them suitable for long-distance communications. In Europe and areas of <a href="/wiki/North_Africa" title="North Africa">Northern Africa</a> and Asia, part of the LF spectrum is used for <a href="/wiki/AM_broadcasting" title="AM broadcasting">AM broadcasting</a> as the "<a href="/wiki/Longwave" title="Longwave">longwave</a>" band. In the western hemisphere, its main use is for aircraft beacons, navigation (<a href="/wiki/LORAN" title="LORAN">LORAN</a>, mostly defunct), information, and weather systems. A number of <a href="#Standard_time_signals">time signal broadcasts</a> also use this band. The main mode of transmission used in this band is <a href="/wiki/Ground_wave" title="Ground wave">ground waves</a>, in which LF radio waves travel just above the Earth's surface, following the terrain. LF ground waves can travel over hills, and can travel far beyond the horizon, up to several hundred kilometers from the transmitter. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Propagation">Propagation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=1" title="Edit section: Propagation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Atmosphericnoise.PNG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Atmosphericnoise.PNG/260px-Atmosphericnoise.PNG" decoding="async" width="260" height="204" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Atmosphericnoise.PNG/390px-Atmosphericnoise.PNG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/93/Atmosphericnoise.PNG/520px-Atmosphericnoise.PNG 2x" data-file-width="792" data-file-height="622" /></a><figcaption>Atmospheric <a href="/wiki/Radio_noise" title="Radio noise">radio noise</a> increases with decreasing frequency. At the LF band and below, it is far above the thermal noise floor injected by amplifier circuits in the receiver, so weak signals can be freely amplified to compensate, with no perceivable increase in the noise (<i>see</i> <a href="/wiki/Signal_to_noise_ratio" class="mw-redirect" title="Signal to noise ratio">SNR</a>). Consequently, <i>for reception</i>, even inefficient antennas much smaller than the wavelength are adequate.</figcaption></figure> <p>Because of their long <a href="/wiki/Wavelength" title="Wavelength">wavelength</a>, low frequency <a href="/wiki/Radio_wave" title="Radio wave">radio waves</a> can <a href="/wiki/Diffraction" title="Diffraction">diffract</a> over obstacles like mountain ranges and travel beyond the horizon, following the contour of the Earth. This mode of propagation, called <i><a href="/wiki/Ground_wave" title="Ground wave">ground wave</a></i>, is the main mode in the LF band.<sup id="cite_ref-Seybold_2-0" class="reference"><a href="#cite_note-Seybold-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Ground waves must be <a href="/wiki/Vertical_polarization" class="mw-redirect" title="Vertical polarization">vertically polarized</a> (the <a href="/wiki/Electric_field" title="Electric field">electric field</a> is vertical while the <a href="/wiki/Magnetic_field" title="Magnetic field">magnetic field</a> is horizontal), so vertical <a href="/wiki/Monopole_antenna" title="Monopole antenna">monopole antennas</a> are used for transmitting. The transmission distance is limited by the absorption of ground waves in the Earth. The attenuation of signal strength with distance is lower than at higher frequencies. Low frequency ground waves can be received up to 2,000 kilometres (1,200 mi) from the transmitting antenna. </p><p>Low frequency waves can also occasionally travel long distances by reflecting from the <a href="/wiki/Ionosphere" title="Ionosphere">ionosphere</a> (the actual mechanism is one of <a href="/wiki/Refraction" title="Refraction">refraction</a>), although this method, called <i><a href="/wiki/Skywave" title="Skywave">skywave</a></i> or "skip" propagation, is not as common as at higher frequencies. Reflection occurs at the ionospheric <a href="/wiki/Kennelly%E2%80%93Heaviside_layer" title="Kennelly–Heaviside layer">E layer</a> or <a href="/wiki/F_Region" class="mw-redirect" title="F Region">F layers</a>. Skywave signals can be detected at distances exceeding 300 kilometres (190 mi) from the transmitting antenna.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Uses">Uses</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=2" title="Edit section: Uses"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Radio_broadcasting">Radio broadcasting</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=3" title="Edit section: Radio broadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Longwave" title="Longwave">Longwave</a></div> <p><a href="/wiki/AM_broadcasting" title="AM broadcasting">AM broadcasting</a> is authorized in the <a href="/wiki/Longwave" title="Longwave">longwave</a> band on frequencies between 148.5 and 283.5 kHz in Europe and parts of Asia. </p> <div class="mw-heading mw-heading3"><h3 id="Standard_time_signals">Standard time signals</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=4" title="Edit section: Standard time signals"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Radio_clock#List_of_radio_time_signal_stations" title="Radio clock">Radio clock § List of radio time signal stations</a></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Atomic_clock.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/75/Atomic_clock.jpg/200px-Atomic_clock.jpg" decoding="async" width="200" height="182" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/75/Atomic_clock.jpg/300px-Atomic_clock.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/75/Atomic_clock.jpg/400px-Atomic_clock.jpg 2x" data-file-width="657" data-file-height="599" /></a><figcaption><div class="center" style="width:auto; margin-left:auto; margin-right:auto;">An LF <a href="/wiki/Radio_clock" title="Radio clock">radio clock</a></div></figcaption></figure> <p>In Europe and Japan, many low-cost consumer devices have since the late 1980s contained <a href="/wiki/Radio_clock" title="Radio clock">radio clocks</a> with an LF receiver for these signals. Since these frequencies propagate by <a href="/wiki/Ground_wave" title="Ground wave">ground wave</a> only, the precision of time signals is not affected by varying propagation paths between the transmitter, the ionosphere, and the receiver. In the United States, such devices became feasible for the mass market only after the output power of <a href="/wiki/WWVB" title="WWVB">WWVB</a> was increased in 1997 and 1999. </p><p><a href="/wiki/JJY" title="JJY">JJY</a> transmitting broadcast on the exact same frequency, and has a similar <a href="/wiki/Timecode" title="Timecode">timecode</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Military">Military</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=5" title="Edit section: Military"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Communication_with_submarines" title="Communication with submarines">Communication with submarines</a></div> <p>Radio signals below 50 kHz are capable of penetrating ocean depths to approximately 200 metres (660 ft); the longer the wavelength, the deeper they go. The British, German, Indian, Russian, Swedish, United States,<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> and possibly other <a href="/wiki/Navy" title="Navy">navies</a> communicate with <a href="/wiki/Submarine" title="Submarine">submarines</a> on these frequencies. </p><p>In addition, <a href="/wiki/Royal_Navy" title="Royal Navy">Royal Navy</a> nuclear submarines carrying ballistic missiles are allegedly under standing orders to monitor the <a href="/wiki/BBC_Radio_4" title="BBC Radio 4">BBC Radio 4</a> transmission on 198 kHz in waters near the UK. It is rumoured that they are to construe a sudden halt in transmission, particularly of the morning news programme <a href="/wiki/Today_(BBC_Radio_4)" title="Today (BBC Radio 4)"><i>Today</i></a>, as an indicator that the UK is under attack, whereafter their <a href="/wiki/Letters_of_last_resort" title="Letters of last resort">sealed orders</a> take effect.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>The United States has four LF stations maintaining contact with its submarine force: <a href="/wiki/Aguada,_Puerto_Rico" title="Aguada, Puerto Rico">Aguada, Puerto Rico</a>, <a href="/wiki/Naval_Air_Station_Keflavik" title="Naval Air Station Keflavik">Keflavik, Iceland</a>, <a href="/wiki/Awase_Airfield" title="Awase Airfield">Awase, Okinawa</a>, and <a href="/wiki/Naval_Air_Station_Sigonella" title="Naval Air Station Sigonella">Sigonella, Italy</a>, using AN/FRT-95 solid state transmitters. </p><p>In the U.S., the <a href="/wiki/Ground_Wave_Emergency_Network" class="mw-redirect" title="Ground Wave Emergency Network">Ground Wave Emergency Network</a> or GWEN operated between 150 and 175 kHz, until replaced by satellite communications systems in 1999. GWEN was a land based military radio communications system which could survive and continue to operate even in the case of a nuclear attack. </p> <div class="mw-heading mw-heading3"><h3 id="Experimental_and_amateur">Experimental and amateur</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=6" title="Edit section: Experimental and amateur"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The 2007 <a href="/wiki/World_Radiocommunication_Conference" title="World Radiocommunication Conference">World Radiocommunication Conference</a> (WRC-07) made a worldwide amateur radio allocation in this band. An international 2.1 kHz allocation, the <a href="/wiki/2200-meter_band" title="2200-meter band"><span class="nowrap"><span style="white-space:nowrap">2<span style="margin-left:0.25em">200</span></span> meter band</span></a> (135.7–137.9 kHz) is available to <a href="/wiki/Amateur_radio" title="Amateur radio">amateur radio</a> operators in several countries in Europe,<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> New Zealand, Canada, US,<sup id="cite_ref-ARRL-bandchart_7-0" class="reference"><a href="#cite_note-ARRL-bandchart-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> and French overseas dependencies. </p><p>The world record distance for a two-way contact is over 10,000 km from near <a href="/wiki/Vladivostok" title="Vladivostok">Vladivostok</a> to <a href="/wiki/New_Zealand" title="New Zealand">New Zealand</a>.<sup id="cite_ref-ZLUA0_8-0" class="reference"><a href="#cite_note-ZLUA0-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> As well as conventional <a href="/wiki/Morse_code" title="Morse code">Morse code</a> many operators use very slow computer-controlled Morse code (so-called <a href="/wiki/QRP_operation#QRSS" title="QRP operation">"QRSS"</a>) or specialized digital communications modes. </p><p>The UK allocated a 2.8 kHz sliver of spectrum from 71.6 kHz to 74.4 kHz beginning in April 1996 to UK amateurs who applied for a Notice of Variation to use the band on a noninterference basis with a maximum output power of 1 Watt <a href="/wiki/Effective_radiated_power" title="Effective radiated power">ERP</a>. This was withdrawn on 30 June 2003 after a number of extensions in favor of the cross-European standard 136 kHz band.<sup id="cite_ref-ofcom_9-0" class="reference"><a href="#cite_note-ofcom-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> Very slow Morse Code from G3AQC in the UK was received 3,275 miles (5,271 km) away, across the <a href="/wiki/Atlantic_Ocean" title="Atlantic Ocean">Atlantic Ocean</a>, by W1TAG in the US on 21-22 November 2001 on 72.401 kHz.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> </p><p>In the United States, there is an exemption within FCC Part 15 regulations permitting unlicensed transmissions in the frequency range of 160–190 kHz. Longwave radio hobbyists refer to this as the '<a href="/wiki/LowFER" title="LowFER">LowFER</a>' band, and experimenters, and their transmitters are called '<a href="/wiki/LowFER" title="LowFER">LowFERs</a>'. This frequency range between 160 kHz and 190 kHz is also referred to as the <span class="nowrap"><span style="white-space:nowrap">1<span style="margin-left:0.25em">750</span></span> meter</span> band. Requirements<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> include: </p> <ul><li>The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed one watt.</li> <li>The total length of the transmission line, antenna, and ground lead (if used) shall not exceed 15 meters.</li> <li>All emissions below 160 kHz or above 190 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier.</li> <li>As an alternative to these requirements, a field strength of 2400/F(kHz) microvolts/meter (measured at a distance of 300 meters) may be used (as described in 47CFR15.209).</li> <li>In all cases, operation may not cause harmful interference to licensed services.</li></ul> <p>Many experimenters in this band are amateur radio operators.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Meteorological_information_broadcasts">Meteorological information broadcasts</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=7" title="Edit section: Meteorological information broadcasts"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Expand_section plainlinks metadata ambox mbox-small-left ambox-content" role="presentation"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><a href="/wiki/File:Wiki_letter_w_cropped.svg" class="mw-file-description"><img alt="[icon]" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/20px-Wiki_letter_w_cropped.svg.png" decoding="async" width="20" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/30px-Wiki_letter_w_cropped.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/40px-Wiki_letter_w_cropped.svg.png 2x" data-file-width="44" data-file-height="31" /></a></span></td><td class="mbox-text"><div class="mbox-text-span">This section <b>needs expansion</b>. You can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Low_frequency&action=edit&section=">adding to it</a>. <span class="date-container"><i>(<span class="date">June 2008</span>)</i></span></div></td></tr></tbody></table> <p>A regular service transmitting <a href="/wiki/Radioteletype" title="Radioteletype">RTTY</a> marine meteorological information in <a href="/wiki/SYNOP" title="SYNOP">SYNOP</a> code on LF is the German Meteorological Service (<a href="/wiki/Deutscher_Wetterdienst" title="Deutscher Wetterdienst">Deutscher Wetterdienst</a> or <a rel="nofollow" class="external text" href="http://www.dwd.de">DWD</a>). The DWD operates station DDH47 on 147.3 kHz using standard ITA-2 alphabet with a transmission speed of 50 <a href="/wiki/Baud" title="Baud">baud</a> and FSK modulation with 85 Hz shift.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Radio_navigation_signals">Radio navigation signals</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=8" title="Edit section: Radio navigation signals"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-Expand_section plainlinks metadata ambox mbox-small-left ambox-content" role="presentation"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><a href="/wiki/File:Wiki_letter_w_cropped.svg" class="mw-file-description"><img alt="[icon]" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/20px-Wiki_letter_w_cropped.svg.png" decoding="async" width="20" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/30px-Wiki_letter_w_cropped.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/40px-Wiki_letter_w_cropped.svg.png 2x" data-file-width="44" data-file-height="31" /></a></span></td><td class="mbox-text"><div class="mbox-text-span">This section <b>needs expansion</b>. You can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Low_frequency&action=edit&section=">adding to it</a>. <span class="date-container"><i>(<span class="date">June 2008</span>)</i></span></div></td></tr></tbody></table> <p>In parts of the world where there is no longwave broadcasting service, <a href="/wiki/Non-directional_beacon" title="Non-directional beacon">Non-directional beacons</a> used for aeronavigation operate on 190–300 kHz (and beyond into the MW band). In Europe, Asia and Africa, the NDB allocation starts on 283.5 kHz. </p><p>The <a href="/wiki/LORAN" title="LORAN">LORAN</a>-C radio navigation system operated on 100 kHz. </p><p>In the past, the <a href="/wiki/Decca_Navigator_System" title="Decca Navigator System">Decca Navigator System</a> operated between 70 kHz and 129 kHz. The last Decca chains were closed down in 2000. </p><p><a href="/wiki/Differential_GPS" title="Differential GPS">Differential GPS</a> telemetry transmitters operate between 283.5 and 325 kHz.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p><p>The commercial "<a href="/wiki/Datatrak" title="Datatrak">Datatrak</a>" radio navigation system operates on a number of frequencies, varying by country, between 120–148 kHz. </p> <div class="mw-heading mw-heading3"><h3 id="Other_applications">Other applications</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=9" title="Edit section: Other applications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Some radio frequency identification (<a href="/wiki/RFID" class="mw-redirect" title="RFID">RFID</a>) tags utilize LF. These tags are commonly known as LFIDs or LowFIDs (low frequency identification). The LF RFID tags are <a href="/wiki/Near_field_and_far_field" class="mw-redirect" title="Near field and far field">near-field</a> devices, interacting with the <a href="/wiki/Resonant_inductive_coupling" title="Resonant inductive coupling">inductive near field</a>, rather than with radiated waves (radio waves) that are the only part of the electromagnetic field that persists into the far field. As such, they are technically <i>not</i> radio devices nor radio antennas, even though they do operate at radio frequencies, and are <i>called</i> "antennas" in the RFID trade, but not in <a href="/wiki/Radio_engineering" class="mw-redirect" title="Radio engineering">radio engineering</a>. It is more proper, and technically more informative to think of them as secondary coils of very loosely coupled <a href="/wiki/Transformer" title="Transformer">transformers</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Antennas">Antennas</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=10" title="Edit section: Antennas"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Since the ground waves used in this band require <a href="/wiki/Vertical_polarization" class="mw-redirect" title="Vertical polarization">vertical polarization</a>, vertical antennas are used for transmission. <a href="/wiki/Mast_radiator" title="Mast radiator">Mast radiators</a> are most common, either insulated from the ground and fed at the bottom, or occasionally fed through guy-wires. <a href="/wiki/T-antenna" title="T-antenna">T-antennas</a> and <a href="/wiki/T-antenna#L-antenna" title="T-antenna">inverted L-antennas</a> are used when antenna height is an issue. </p><p>LF transmitting antennas for high power transmitters require large amounts of space, and have been the cause of controversy in Europe and the United States, due to concerns about possible health hazards associated with <a href="/wiki/Electromagnetic_radiation_and_health" title="Electromagnetic radiation and health">human exposure to radio waves</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Longwave_receiving_antennas">Longwave receiving antennas</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=11" title="Edit section: Longwave receiving antennas"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Low_cost_DCF77_receiver.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Low_cost_DCF77_receiver.jpg/220px-Low_cost_DCF77_receiver.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Low_cost_DCF77_receiver.jpg/330px-Low_cost_DCF77_receiver.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Low_cost_DCF77_receiver.jpg/440px-Low_cost_DCF77_receiver.jpg 2x" data-file-width="720" data-file-height="480" /></a><figcaption>Low cost LF <a href="/wiki/Time_signal" title="Time signal">time signal</a> <a href="/wiki/Radio_receiver_design" title="Radio receiver design"><i>crystal receiver</i></a> using ferrite <a href="/wiki/Loop_antenna" title="Loop antenna">loop antenna</a>.</figcaption></figure> <p>Antenna requirements for LF reception are much more modest than for transmission. Although non-resonant long wire antennas are sometimes used, ferrite <a href="/wiki/Loop_antenna" title="Loop antenna">loop antennas</a> are far more popular because of their small size. </p><p>Amateur radio operators have achieved good LF reception using <a href="/wiki/Active_antenna" title="Active antenna">active antennas</a>: A short whip with a built-in <a href="/wiki/Pre-amplifier" class="mw-redirect" title="Pre-amplifier">pre-amplifier</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Antenna_heights">Antenna heights</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=12" title="Edit section: Antenna heights"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Due to the long wavelengths in the band, nearly all LF antennas are <a href="/wiki/Electrically_short" class="mw-redirect" title="Electrically short">electrically short</a>, shorter than one quarter of the radiated wavelength, so their low radiation resistance makes them inefficient, requiring very low resistance grounds and conductors to avoid dissipating transmitter power. These electrically short antennas need <a href="/wiki/Loading_coil" title="Loading coil">loading coils</a> at the base of the antenna to bring them into resonance. Many antenna types, such as the <a href="/wiki/Umbrella_antenna" title="Umbrella antenna">umbrella antenna</a> and L- and T-antenna, use capacitive top-loading (a "top hat"), in the form of a network of horizontal wires attached to the top of the vertical radiator. The <a href="/wiki/Capacitance" title="Capacitance">capacitance</a> improves the efficiency of the antenna by increasing the current, without increasing its height. </p><p>The height of antennas differ by usage. For some <a href="/wiki/Non-directional_beacon" title="Non-directional beacon">non-directional beacons</a> (NDBs) the height can be as low as 10 meters, while for more powerful navigation transmitters such as <a href="/wiki/Decca_Navigator_System" title="Decca Navigator System">DECCA</a>, masts with a height around 100 meters are used. <a href="/wiki/T-antenna" title="T-antenna">T-antennas</a> have a height between 50–200 meters, while mast aerials are usually taller than 150 meters. </p><p>The height of mast antennas for <a href="/wiki/LORAN-C" class="mw-redirect" title="LORAN-C">LORAN-C</a> is around 190 meters for transmitters with radiated power below 500 kW, and around 400 meters for transmitters greater than <span class="nowrap"><span style="white-space:nowrap">1<span style="margin-left:0.25em">000</span></span> kilowatts.</span> The main type of LORAN-C antenna is insulated from ground. </p><p>LF <a href="/wiki/Longwave" title="Longwave">(longwave) broadcasting stations</a> use mast antennas with heights of more than 150 meters or <a href="/wiki/T-antenna" title="T-antenna">T-aerials</a>. The mast antennas can be ground-fed insulated masts or upper-fed grounded masts. It is also possible to use cage antennas on grounded masts. </p> <div class="mw-heading mw-heading3"><h3 id="Directional_array_antennas">Directional array antennas</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=13" title="Edit section: Directional array antennas"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>For broadcasting stations, directional antennas are often required. They consist of multiple masts, which often have the same height. Some longwave antennas consist of multiple mast antennas arranged in a circle with or without a mast antenna in the center. Such antennas focus the transmitted power toward ground and give a large zone of fade-free reception. This type of antenna is rarely used, because they are very expensive and require much space and because fading occurs on longwave much more rarely than in the medium wave range. One antenna of this kind was used by <a href="/wiki/Transmitter_Orlunda" class="mw-redirect" title="Transmitter Orlunda">transmitter Orlunda</a> in Sweden. </p> <div class="mw-heading mw-heading2"><h2 id="Footnotes">Footnotes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=14" title="Edit section: Footnotes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"> Low-frequency experimenter Lawrence "Laurie" Mayhead, G3AQC, has added another LF accomplishment to his list – trans-Atlantic reception of his 73 kHz signal. [...] Mayhead reports that on the night of 21-22 November, his signal on 72.401 kHz was received in the US. "I managed to transmit a full call sign to John Andrews, W1TAG, in Holden, Massachusetts", he said. Mayhead was using dual-frequency CW – or DFCW – featuring elements that are two minutes long; Andrews detected his signal using ARGO <span class="nowrap">DSP software. — <a href="/wiki/ARRL" class="mw-redirect" title="ARRL">ARRL</a> Nov 2001<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=15" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 12em;"> <ul><li><a href="/wiki/2200-meter_band" title="2200-meter band">2200-meter band</a></li> <li><a href="/wiki/Ground_Wave_Emergency_Network" class="mw-redirect" title="Ground Wave Emergency Network">Ground Wave Emergency Network</a> (GWEN)</li> <li><a href="/wiki/Longwave" title="Longwave">Longwave</a></li> <li><a href="/wiki/LowFER" title="LowFER">LowFER</a></li> <li><a href="/wiki/Passive_RFID" class="mw-redirect" title="Passive RFID">Passive RFID</a></li> <li><a href="/wiki/Time_signal#Radio_time_sources" title="Time signal">Time signal</a></li> <li><a href="/wiki/WGU-20" title="WGU-20">WGU-20</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=16" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist reflist-columns references-column-width" style="column-width: 25em;"> <ol class="references"> <li id="cite_note-ITU_Nomenclature-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-ITU_Nomenclature_1-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="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">"Rec. ITU-R V.431-7, Nomenclature of the frequency and wavelength bands used in telecommunications"</a> <span class="cs1-format">(PDF)</span>. ITU. Archived from <a rel="nofollow" class="external text" href="http://www.itu.int/dms_pubrec/itu-r/rec/v/R-REC-V.431-7-200005-I!!PDF-E.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 31 October 2013<span class="reference-accessdate">. Retrieved <span class="nowrap">20 February</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Rec.+ITU-R+V.431-7%2C+Nomenclature+of+the+frequency+and+wavelength+bands+used+in+telecommunications&rft.pub=ITU&rft_id=http%3A%2F%2Fwww.itu.int%2Fdms_pubrec%2Fitu-r%2Frec%2Fv%2FR-REC-V.431-7-200005-I%21%21PDF-E.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-Seybold-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-Seybold_2-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSeybold2005" class="citation book cs1"><a href="/wiki/John_S._Seybold" class="mw-redirect" title="John S. Seybold">Seybold, John S.</a> (2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=4LtmjGNwOPIC&q=cross+polarization+discrimination&pg=PA57"><i>Introduction to RF Propagation</i></a>. John Wiley and Sons. pp. 55–58. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0471743682" title="Special:BookSources/0471743682"><bdi>0471743682</bdi></a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210416234908/https://books.google.com/books?id=4LtmjGNwOPIC&q=cross+polarization+discrimination&pg=PA57">Archived</a> from the original on 16 April 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">30 November</span> 2020</span> – via Google books.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Introduction+to+RF+Propagation&rft.pages=55-58&rft.pub=John+Wiley+and+Sons&rft.date=2005&rft.isbn=0471743682&rft.aulast=Seybold&rft.aufirst=John+S.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D4LtmjGNwOPIC%26q%3Dcross%2Bpolarization%2Bdiscrimination%26pg%3DPA57&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMelia" class="citation magazine cs1">Melia, Alan (G3NYK). "Understanding LF propagation". <i><a href="/wiki/Radcom" class="mw-redirect" title="Radcom">Radcom</a></i>. Vol. 85, no. 9. Bedford, UK: <a href="/wiki/Radio_Society_of_Great_Britain" title="Radio Society of Great Britain">Radio Society of Great Britain</a>. p. 32.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Radcom&rft.atitle=Understanding+LF+propagation&rft.volume=85&rft.issue=9&rft.pages=32&rft.aulast=Melia&rft.aufirst=Alan+%28G3NYK%29&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_magazine" title="Template:Cite magazine">cite magazine</a>}}</code>: CS1 maint: numeric names: authors list (<a href="/wiki/Category:CS1_maint:_numeric_names:_authors_list" title="Category:CS1 maint: numeric names: authors list">link</a>)</span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.fas.org/nuke/guide/usa/c3i/vlf.htm">"Very Low Frequency (VLF)"</a>. United States Nuclear Forces. <i>fas.org</i>. 1998. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20071227165518/http://www.fas.org/nuke/guide/usa/c3i/vlf.htm">Archived</a> from the original on 27 December 2007<span class="reference-accessdate">. Retrieved <span class="nowrap">9 January</span> 2008</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=fas.org&rft.atitle=Very+Low+Frequency+%28VLF%29&rft.date=1998&rft_id=http%3A%2F%2Fwww.fas.org%2Fnuke%2Fguide%2Fusa%2Fc3i%2Fvlf.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation episode cs1"><a rel="nofollow" class="external text" href="https://www.bbc.co.uk/programmes/b00fq2sy">"The Human Button"</a>. <i><a href="/wiki/Today_(BBC_Radio_4)" title="Today (BBC Radio 4)">Today</a></i>. 2 December 2008. <a href="/wiki/BBC" title="BBC">BBC</a>. <a href="/wiki/BBC_Radio_4" title="BBC Radio 4">BBC Radio 4</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110203232901/http://www.bbc.co.uk/programmes/b00fq2sy">Archived</a> from the original on 3 February 2011<span class="reference-accessdate">. Retrieved <span class="nowrap">6 August</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Today&rft.date=2008-12-02&rft_id=http%3A%2F%2Fwww.bbc.co.uk%2Fprogrammes%2Fb00fq2sy&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation report cs1">"Use of the band 135.7–137.8 kHz by the Amateur Service". ERC <span class="nowrap">Recommendation 62-01 E</span> (Report). Mainz, DE: <a href="/wiki/European_Conference_of_Postal_and_Telecommunications_Administrations" title="European Conference of Postal and Telecommunications Administrations">European Conference of Postal and Telecommunications Administrations</a> (CEPT). 1997. <span class="nowrap">ERC Rec 62-01 E</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=ERC+%3Cspan+class%3D%22nowrap%22%3ERecommendation+62-01+E%3C%2Fspan%3E&rft.place=Mainz%2C+DE&rft.pub=European+Conference+of+Postal+and+Telecommunications+Administrations+%28CEPT%29&rft.date=1997&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-ARRL-bandchart-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-ARRL-bandchart_7-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation audio-visual cs1"><a rel="nofollow" class="external text" href="http://www.arrl.org/files/file/Regulatory/Band%20Chart/Band%20Chart%20-%2011X17%20Color.pdf"><i>Regulatory Band Chart</i></a> <span class="cs1-format">(PDF)</span> (chart / graphic) (11×17″ color ed.). Newington, CT: <a href="/wiki/American_Radio_Relay_League" title="American Radio Relay League">American Radio Relay League</a>. 22 September 2017. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20201111222535/http://www.arrl.org/files/file/Regulatory/Band%20Chart/Band%20Chart%20-%2011X17%20Color.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 11 November 2020<span class="reference-accessdate">. Retrieved <span class="nowrap">26 November</span> 2020</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Regulatory+Band+Chart&rft.place=Newington%2C+CT&rft.edition=11%C3%9717%E2%80%B3+color&rft.pub=American+Radio+Relay+League&rft.date=2017-09-22&rft_id=http%3A%2F%2Fwww.arrl.org%2Ffiles%2Ffile%2FRegulatory%2FBand%2520Chart%2FBand%2520Chart%2520-%252011X17%2520Color.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-ZLUA0-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-ZLUA0_8-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="http://www.wireless.org.uk/newspic92.htm">"QSO ZL / UA0 on 136 kHz"</a>. The World of LF. <i>wireless.org.uk</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20070929025210/http://www.wireless.org.uk/newspic92.htm">Archived</a> from the original on 29 September 2007<span class="reference-accessdate">. Retrieved <span class="nowrap">1 June</span> 2006</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=wireless.org.uk&rft.atitle=QSO+ZL+%2F+UA0+on+136+kHz&rft_id=http%3A%2F%2Fwww.wireless.org.uk%2Fnewspic92.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-ofcom-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-ofcom_9-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation pressrelease cs1"><a rel="nofollow" class="external text" href="http://www.ofcom.org.uk/static/archive/ra/topics/spectrum-strat/future/strat02/strategy02app_a.doc">"UK Spectrum Strategy 2002"</a> (Press release). <a href="/wiki/Ofcom" title="Ofcom">Ofcom</a>. 16 September 2016. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20070930031406/http://www.ofcom.org.uk/static/archive/ra/topics/spectrum-strat/future/strat02/strategy02app_a.doc">Archived</a> from the original on 30 September 2007<span class="reference-accessdate">. Retrieved <span class="nowrap">5 June</span> 2006</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=UK+Spectrum+Strategy+2002&rft.pub=Ofcom&rft.date=2016-09-16&rft_id=http%3A%2F%2Fwww.ofcom.org.uk%2Fstatic%2Farchive%2Fra%2Ftopics%2Fspectrum-strat%2Ffuture%2Fstrat02%2Fstrategy02app_a.doc&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="http://www.arrl.org/arrlletter?issue=2001-11-30">"G3AQC's signal spans the Atlantic on 73 kHz!"</a>. <i>The ARRL Letter</i>. Newington, CT: <a href="/wiki/American_Radio_Relay_League" title="American Radio Relay League">American Radio Relay League</a>. 30 November 2001. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140112215834/http://www.arrl.org/arrlletter?issue=2001-11-30">Archived</a> from the original on 12 January 2014<span class="reference-accessdate">. Retrieved <span class="nowrap">12 January</span> 2014</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+ARRL+Letter&rft.atitle=G3AQC%27s+signal+spans+the+Atlantic+on+73+kHz%21&rft.date=2001-11-30&rft_id=http%3A%2F%2Fwww.arrl.org%2Farrlletter%3Fissue%3D2001-11-30&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation report cs1">"§ 15.217 Operation in the band 160–190 kHz (<span class="nowrap">47 CFR 15.217</span>)". <a rel="nofollow" class="external text" href="http://www.ecfr.gov/cgi-bin/text-idx?SID=ea364b89f317550d594a9315deca6022&mc=true&node=pt47.1.15&rgn=div5#se47.1.15_1209">Part 15 — Radio frequency devices</a>. <i>ecfr.gov</i> (Report). The Electronic Code of Federal Regulations. <span class="nowrap">47 CFR 15.217</span> (<span class="nowrap">47 CFR 15.206</span>)<span class="reference-accessdate">. Retrieved <span class="nowrap">17 March</span> 2024</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=Part+15+%E2%80%94+Radio+frequency+devices&rft.series=The+Electronic+Code+of+Federal+Regulations&rft_id=http%3A%2F%2Fwww.ecfr.gov%2Fcgi-bin%2Ftext-idx%3FSID%3Dea364b89f317550d594a9315deca6022%26mc%3Dtrue%26node%3Dpt47.1.15%26rgn%3Ddiv5%23se47.1.15_1209&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span><sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability"><span title="The material near this tag failed verification of its source citation(s). (March 2024)">failed verification</span></a></i>]</sup> Cited section <span class="nowrap">47 CFR 15.206</span> not present / removed: section id §15.205 skips to §15.207 .</span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ecfr.gov/cgi-bin/text-idx?SID=7f66d50bc733c74f45ff68ec5dda7d93&node=47:1.0.1.1.16&rgn=div5#47:1.0.1.1.16.3">"Part 15 — Rado frequency devices"</a>. Federal Register. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140726053324/http://www.ecfr.gov/cgi-bin/text-idx?SID=7f66d50bc733c74f45ff68ec5dda7d93&node=47:1.0.1.1.16&rgn=div5#47:1.0.1.1.16.3">Archived</a> from the original on 26 July 2014<span class="reference-accessdate">. Retrieved <span class="nowrap">21 July</span> 2014</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Part+15+%E2%80%94+Rado+frequency+devices&rft.series=Federal+Register&rft_id=http%3A%2F%2Fwww.ecfr.gov%2Fcgi-bin%2Ftext-idx%3FSID%3D7f66d50bc733c74f45ff68ec5dda7d93%26node%3D47%3A1.0.1.1.16%26rgn%3Ddiv5%2347%3A1.0.1.1.16.3&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://archive.today/20120730093823/http://www.dwd.de/de/wir/Geschaeftsfelder/Seeschifffahrt/Sendeplaene/Sendeplaene.htm">"DWD Sendeplan"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.dwd.de/de/wir/Geschaeftsfelder/Seeschifffahrt/Sendeplaene/Sendeplaene.htm">the original</a> on 30 July 2012<span class="reference-accessdate">. Retrieved <span class="nowrap">8 January</span> 2008</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=DWD+Sendeplan&rft_id=http%3A%2F%2Fwww.dwd.de%2Fde%2Fwir%2FGeschaeftsfelder%2FSeeschifffahrt%2FSendeplaene%2FSendeplaene.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGale2011" class="citation report cs1">Gale, Alan (G4TMV) (2011). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110721225343/http://www.ndblist.info/datamodes/worldDGPSfreqorder.pdf">World DGPS database for DXers</a> <span class="cs1-format">(PDF)</span> (Report). 4.6. Archived from <a rel="nofollow" class="external text" href="http://www.ndblist.info/datamodes/worldDGPSfreqorder.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 21 July 2011<span class="reference-accessdate">. Retrieved <span class="nowrap">14 January</span> 2008</span> – via ndblist.info.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=World+DGPS+database+for+DXers&rft.series=4.6&rft.date=2011&rft.aulast=Gale&rft.aufirst=Alan+%28G4TMV%29&rft_id=http%3A%2F%2Fwww.ndblist.info%2Fdatamodes%2FworldDGPSfreqorder.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_report" title="Template:Cite report">cite report</a>}}</code>: CS1 maint: numeric names: authors list (<a href="/wiki/Category:CS1_maint:_numeric_names:_authors_list" title="Category:CS1 maint: numeric names: authors list">link</a>)</span></span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=17" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin refbegin-columns references-column-width" style="column-width: 25em"> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKlawitterOexnerHerold2000" class="citation book cs1 cs1-prop-foreign-lang-source">Klawitter, G.; Oexner, M.; Herold, K. (2000). <i>Langwelle und Längstwelle</i> [<i>Longwave and Longest Wave</i>] (in German). Meckenheim, DE: Siebel Verlag GmbH. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/3-89632-043-2" title="Special:BookSources/3-89632-043-2"><bdi>3-89632-043-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Langwelle+und+L%C3%A4ngstwelle&rft.place=Meckenheim%2C+DE&rft.pub=Siebel+Verlag+GmbH&rft.date=2000&rft.isbn=3-89632-043-2&rft.aulast=Klawitter&rft.aufirst=G.&rft.au=Oexner%2C+M.&rft.au=Herold%2C+K.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMarten2007" class="citation book cs1 cs1-prop-foreign-lang-source">Marten, M. (2007). <i>Spezial-Frequenzliste 2007/2008</i> [<i>Special Frequency List 2007–2008</i>] (in German). Meckenheim, DE: Siebel Verlag GmbH. pp. 36–39. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-88180-665-7" title="Special:BookSources/978-3-88180-665-7"><bdi>978-3-88180-665-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Spezial-Frequenzliste+2007%2F2008&rft.place=Meckenheim%2C+DE&rft.pages=36-39&rft.pub=Siebel+Verlag+GmbH&rft.date=2007&rft.isbn=978-3-88180-665-7&rft.aulast=Marten&rft.aufirst=M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDennisonMoritz2007" class="citation book cs1">Dennison, Mike (G3XDV); Moritz, Jim (M0BMU) (2007). <i>LF Today</i>. Potters Bar, UK: <a href="/wiki/Radio_Society_of_Great_Britain" title="Radio Society of Great Britain">Radio Society of Great Britain</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-905086-36-8" title="Special:BookSources/978-1-905086-36-8"><bdi>978-1-905086-36-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=LF+Today&rft.place=Potters+Bar%2C+UK&rft.pub=Radio+Society+of+Great+Britain&rft.date=2007&rft.isbn=978-1-905086-36-8&rft.aulast=Dennison&rft.aufirst=Mike+%28G3XDV%29&rft.au=Moritz%2C+Jim+%28M0BMU%29&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: CS1 maint: numeric names: authors list (<a href="/wiki/Category:CS1_maint:_numeric_names:_authors_list" title="Category:CS1 maint: numeric names: authors list">link</a>)</span></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Low_frequency&action=edit&section=18" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239549316"><div class="refbegin refbegin-columns references-column-width" style="column-width: 25em"> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStimac" class="citation web cs1">Stimac, Tomislav (IK1QFK). <a rel="nofollow" class="external text" href="http://www.vlf.it/frequency/bands.html">"Definition of frequency bands (VLF, ELF... <i>etc</i>.)"</a>. <i>vlf.it</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=vlf.it&rft.atitle=Definition+of+frequency+bands+%28VLF%2C+ELF...+etc.%29&rft.aulast=Stimac&rft.aufirst=Tomislav+%28IK1QFK%29&rft_id=http%3A%2F%2Fwww.vlf.it%2Ffrequency%2Fbands.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_web" title="Template:Cite web">cite web</a>}}</code>: CS1 maint: numeric names: authors list (<a href="/wiki/Category:CS1_maint:_numeric_names:_authors_list" title="Category:CS1 maint: numeric names: authors list">link</a>)</span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.vlf.it">"IK1QFK"</a>. <i>vlf.it</i> (home page).</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=vlf.it&rft.atitle=IK1QFK&rft_id=http%3A%2F%2Fwww.vlf.it&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALow+frequency" class="Z3988"></span></li></ul> </div> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output 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dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Links_to_related_articles" style="padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2" style="background:#e8e8ff;"><div id="Links_to_related_articles" style="font-size:114%;margin:0 4em">Links to related articles</div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0;font-size:114%"><div style="padding:0px"> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Radio_spectrum_(ITU)" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Radio_spectrum" title="Template:Radio spectrum"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Radio_spectrum" title="Template talk:Radio spectrum"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Radio_spectrum" title="Special:EditPage/Template:Radio spectrum"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Radio_spectrum_(ITU)" style="font-size:114%;margin:0 4em"><a href="/wiki/Radio_spectrum" title="Radio spectrum">Radio spectrum</a> (ITU)</div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0;background:transparent;color:inherit;"><div style="padding:0px"><table class="navbox-columns-table" style="border-spacing: 0px; text-align:left;width:auto; margin-left:auto; margin-right:auto;"><tbody><tr style="vertical-align:top"><td class="navbox-list" style="padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Extremely_low_frequency" title="Extremely low frequency">ELF</a></b> <br /> 3 Hz/100 Mm <br /> 30 Hz/10 Mm </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Super_low_frequency" title="Super low frequency">SLF</a></b> <br /> 30 Hz/10 Mm <br /> 300 Hz/1 Mm </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Ultra_low_frequency" title="Ultra low frequency">ULF</a></b> <br /> 300 Hz/1 Mm <br /> 3 kHz/100 km </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Very_low_frequency" title="Very low frequency">VLF</a></b> <br /> 3 kHz/100 km <br /> 30 kHz/10 km </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a class="mw-selflink selflink">LF</a></b> <br /> 30 kHz/10 km <br /> 300 kHz/1 km </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Medium_frequency" title="Medium frequency">MF</a></b> <br /> 300 kHz/1 km <br /> 3 MHz/100 m </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/High_frequency" title="High frequency">HF</a></b> <br /> 3 MHz/100 m <br /> 30 MHz/10 m </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Very_high_frequency" title="Very high frequency">VHF</a></b> <br /> 30 MHz/10 m <br /> 300 MHz/1 m </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Ultra_high_frequency" title="Ultra high frequency">UHF</a></b> <br /> 300 MHz/1 m <br /> 3 GHz/100 mm </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Super_high_frequency" title="Super high frequency">SHF</a></b> <br /> 3 GHz/100 mm <br /> 30 GHz/10 mm </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Extremely_high_frequency" title="Extremely high frequency">EHF</a></b> <br /> 30 GHz/10 mm <br /> 300 GHz/1 mm </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:10em;"><div> <p><b><a href="/wiki/Tremendously_high_frequency" class="mw-redirect" title="Tremendously high frequency">THF</a></b> <br /> 300 GHz/1 mm <br /> 3 THz/0.1 mm </p> </div></td></tr></tbody></table></div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div><b><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/1/1d/Radio_icon.png" decoding="async" width="32" height="23" class="mw-file-element" data-file-width="30" data-file-height="22" /></span></span> </span><a href="/wiki/Portal:Radio" title="Portal:Radio">Radio portal</a></b></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r886047488">.mw-parser-output .nobold{font-weight:normal}</style></div><div role="navigation" class="navbox" aria-labelledby="Electromagnetic_spectrum" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Electromagnetic_spectrum" title="Template:Electromagnetic spectrum"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Electromagnetic_spectrum" title="Template talk:Electromagnetic spectrum"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Electromagnetic_spectrum" title="Special:EditPage/Template:Electromagnetic spectrum"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Electromagnetic_spectrum" style="font-size:114%;margin:0 4em"><a href="/wiki/Electromagnetic_spectrum" title="Electromagnetic spectrum">Electromagnetic spectrum</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2" style="padding:0.3em 0.5em 0.4em;line-height:1.25em;font-weight:bold;"><div> <ul><li><a href="/wiki/Gamma_ray" title="Gamma ray">Gamma rays</a></li> <li><a href="/wiki/X-ray" title="X-ray">X-rays</a></li> <li><a href="/wiki/Ultraviolet" title="Ultraviolet">Ultraviolet</a></li> <li><a href="/wiki/Visible_spectrum" title="Visible spectrum">Visible</a></li> <li><a href="/wiki/Infrared" title="Infrared">Infrared</a></li> <li><a href="/wiki/Microwave" title="Microwave">Microwave</a></li> <li><a href="/wiki/Radio_wave" title="Radio wave">Radio</a><figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:Frequency_vs._wave_length.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/62/Frequency_vs._wave_length.svg/500px-Frequency_vs._wave_length.svg.png" decoding="async" width="500" height="65" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/62/Frequency_vs._wave_length.svg/750px-Frequency_vs._wave_length.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/62/Frequency_vs._wave_length.svg/1000px-Frequency_vs._wave_length.svg.png 2x" data-file-width="800" data-file-height="104" /></a><figcaption></figcaption></figure><div style="clear:both;" class=""></div><span class="nobold"><i><span style="font-size:120%">←</span> higher <a href="/wiki/Frequency" title="Frequency">frequencies</a><span class="nowrap">       </span>longer <a href="/wiki/Wavelength" title="Wavelength">wavelengths</a> <span style="font-size:120%">→</span></i></span></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Gamma_ray" title="Gamma ray">Gamma rays</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Very-high-energy_gamma_ray" title="Very-high-energy gamma ray">Very-high-energy gamma ray</a></li> <li><a href="/wiki/Ultra-high-energy_gamma_ray" title="Ultra-high-energy gamma ray">Ultra-high-energy gamma ray</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/X-ray" title="X-ray">X-rays</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Soft_X-ray" class="mw-redirect" title="Soft X-ray">Soft X-ray</a></li> <li><a href="/wiki/Hard_X-ray" class="mw-redirect" title="Hard X-ray">Hard X-ray</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Ultraviolet" title="Ultraviolet">Ultraviolet</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Extreme_ultraviolet" title="Extreme ultraviolet">Extreme ultraviolet</a></li> <li><a href="/wiki/Vacuum_ultraviolet" class="mw-redirect" title="Vacuum ultraviolet">Vacuum ultraviolet</a></li> <li><a href="/wiki/Lyman-alpha" title="Lyman-alpha">Lyman-alpha</a></li> <li><a href="/wiki/Far_ultraviolet" class="mw-redirect" title="Far ultraviolet">FUV</a></li> <li><a href="/wiki/Middle_ultraviolet" class="mw-redirect" title="Middle ultraviolet">MUV</a></li> <li><a href="/wiki/Near_ultraviolet" class="mw-redirect" title="Near ultraviolet">NUV</a></li> <li><a href="/wiki/Ultraviolet_C" class="mw-redirect" title="Ultraviolet C">UVC</a></li> <li><a href="/wiki/Ultraviolet_B" class="mw-redirect" title="Ultraviolet B">UVB</a></li> <li><a href="/wiki/Ultraviolet_A" class="mw-redirect" title="Ultraviolet A">UVA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Visible_spectrum" title="Visible spectrum">Visible (optical)</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Violet_(color)" title="Violet (color)">Violet</a></li> <li><a href="/wiki/Blue" title="Blue">Blue</a></li> <li><a href="/wiki/Cyan" title="Cyan">Cyan</a></li> <li><a href="/wiki/Green" title="Green">Green</a></li> <li><a href="/wiki/Yellow" title="Yellow">Yellow</a></li> <li><a href="/wiki/Orange_(colour)" title="Orange (colour)">Orange</a></li> <li><a href="/wiki/Red" title="Red">Red</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Infrared" title="Infrared">Infrared</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Near-infrared" class="mw-redirect" title="Near-infrared">NIR</a> (<a href="/wiki/Photometric_system" title="Photometric system">Bands</a>: <a href="/wiki/J_band_(infrared)" title="J band (infrared)">J</a>, <a href="/wiki/K_band_(infrared)" title="K band (infrared)">K</a>, <a href="/wiki/H_band_(infrared)" title="H band (infrared)">H</a>)</li> <li><a href="/wiki/Infrared#Regions" title="Infrared">SWIR</a></li> <li><a href="/wiki/Infrared#Regions" title="Infrared">MWIR</a> (<a href="/wiki/Photometric_system" title="Photometric system">Bands</a>: <a href="/wiki/L_band_(infrared)" title="L band (infrared)">L</a>, <a href="/wiki/M_band_(infrared)" title="M band (infrared)">M</a>, <a href="/wiki/N_band" title="N band">N</a>)</li> <li><a href="/wiki/Infrared#Regions" title="Infrared">LWIR</a></li> <li><a href="/wiki/Far_infrared" title="Far infrared">FIR</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Microwave" title="Microwave">Microwaves</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/W_band" title="W band">W band</a></li> <li><a href="/wiki/V_band" title="V band">V band</a></li> <li><a href="/wiki/Q_band" title="Q band">Q band</a></li> <li><a href="/wiki/Ka_band" title="Ka band">K<sub>a</sub> band</a></li> <li><a href="/wiki/K_band_(IEEE)" title="K band (IEEE)">K band</a></li> <li><a href="/wiki/Ku_band" title="Ku band">K<sub>u</sub> band</a></li> <li><a href="/wiki/X_band" title="X band">X band</a></li> <li><a href="/wiki/C_band_(IEEE)" title="C band (IEEE)">C band</a></li> <li><a href="/wiki/S_band" title="S band">S band</a></li> <li><a href="/wiki/L_band" title="L band">L band</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Radio_frequency" title="Radio frequency">Radio</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Terahertz_radiation" title="Terahertz radiation">THF</a></li> <li><a href="/wiki/Extremely_high_frequency" title="Extremely high frequency">EHF</a></li> <li><a href="/wiki/Super_high_frequency" title="Super high frequency">SHF</a></li> <li><a href="/wiki/Ultra_high_frequency" title="Ultra high frequency">UHF</a></li> <li><a href="/wiki/Very_high_frequency" title="Very high frequency">VHF</a></li> <li><a href="/wiki/High_frequency" title="High frequency">HF</a></li> <li><a href="/wiki/Medium_frequency" title="Medium frequency">MF</a></li> <li><a class="mw-selflink selflink">LF</a></li> <li><a href="/wiki/Very_low_frequency" title="Very low frequency">VLF</a></li> <li><a href="/wiki/Ultra_low_frequency" title="Ultra low frequency">ULF</a></li> <li><a href="/wiki/Super_low_frequency" title="Super low frequency">SLF</a></li> <li><a href="/wiki/Extremely_low_frequency" title="Extremely low frequency">ELF</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background:lavender;"><a href="/wiki/Wavelength" title="Wavelength">Wavelength</a> types</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Microwave" title="Microwave">Microwave</a></li> <li><a href="/wiki/Shortwave_radio" title="Shortwave radio">Shortwave</a></li> <li><a href="/wiki/Medium_wave" title="Medium wave">Medium wave</a></li> <li><a href="/wiki/Longwave" title="Longwave">Longwave</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Analog_and_digital_audio_broadcasting" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Audio_broadcasting" title="Template:Audio broadcasting"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Audio_broadcasting" title="Template talk:Audio broadcasting"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Audio_broadcasting" title="Special:EditPage/Template:Audio broadcasting"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Analog_and_digital_audio_broadcasting" style="font-size:114%;margin:0 4em"><a href="/wiki/Analog_recording" title="Analog recording">Analog</a> and <a href="/wiki/Digital_audio" title="Digital audio">digital audio</a> <a href="/wiki/Broadcasting" title="Broadcasting">broadcasting</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Terrestrial</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Radio" title="Radio">Radio</a> <a href="/wiki/Modulation" title="Modulation">modulation</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Amplitude_modulation" title="Amplitude modulation">AM</a></li> <li><a href="/wiki/Frequency_modulation" title="Frequency modulation">FM</a></li> <li><a href="/wiki/Orthogonal_frequency-division_multiplexing" title="Orthogonal frequency-division multiplexing">COFDM</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Frequency_allocation" title="Frequency allocation">Frequency allocations</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Longwave" title="Longwave">LW</a> (<a class="mw-selflink selflink">LF</a>)</li> <li><a href="/wiki/Medium_wave" title="Medium wave">MW</a> (<a href="/wiki/Medium_frequency" title="Medium frequency">MF</a>)</li> <li><a href="/wiki/Shortwave_radio" title="Shortwave radio">SW</a> (<a href="/wiki/High_frequency" title="High frequency">HF</a>)</li> <li><a href="/wiki/Very_high_frequency" title="Very high frequency">VHF</a> (<a href="/wiki/Band_I" title="Band I">low</a> / <a href="/wiki/Band_II" title="Band II">mid</a> / <a href="/wiki/Band_III" title="Band III">high</a>)</li> <li><a href="/wiki/L_band" title="L band">L band</a> (<a href="/wiki/Ultra_high_frequency" title="Ultra high frequency">UHF</a>)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Digital systems</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CAM-D" title="CAM-D">CAM-D</a></li> <li><a href="/wiki/Digital_Audio_Broadcasting" title="Digital Audio Broadcasting">DAB/DAB+</a></li> <li><a href="/wiki/Digital_Radio_Mondiale" title="Digital Radio Mondiale">DRM/DRM+</a></li> <li><a href="/wiki/ISDB-T#ISDB-Tsb" class="mw-redirect" title="ISDB-T">ISDB-Tsb</a></li> <li><a href="/wiki/FMeXtra" title="FMeXtra">FMeXtra</a></li> <li><a href="/wiki/HD_Radio" title="HD Radio">HD Radio</a></li> <li>CDR</li> <li><a href="/wiki/DVB-T2" title="DVB-T2">DVB-T2 Lite</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Satellite</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Frequency allocations</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/C_band_(IEEE)" title="C band (IEEE)">C band</a></li> <li><a href="/wiki/Ku_band" title="Ku band">K<sub>u</sub> band</a></li> <li><a href="/wiki/L_band" title="L band">L band</a></li> <li><a href="/wiki/S_band" title="S band">S band</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Digital systems</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Astra_Digital_Radio" title="Astra Digital Radio">ADR</a></li> <li><a href="/wiki/Digital_audio_broadcasting" class="mw-redirect" title="Digital audio broadcasting">DAB-S</a></li> <li><a href="/wiki/DVB-SH" title="DVB-SH">DVB-SH</a></li> <li><a href="/wiki/S-DMB" title="S-DMB">S-DMB</a></li> <li><a href="/wiki/ETSI_Satellite_Digital_Radio" title="ETSI Satellite Digital Radio">SDR</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Commercial_broadcasting" title="Commercial broadcasting">Commercial radio</a> providers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Sirius_XM" title="Sirius XM">Sirius XM</a> <ul><li><a href="/wiki/Sirius_XM_Canada" title="Sirius XM Canada">Canada</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Audio_codec" title="Audio codec">Codecs</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">AAC</a></li> <li><a href="/wiki/Extended_Adaptive_Multi-Rate_%E2%80%93_Wideband" title="Extended Adaptive Multi-Rate – Wideband">AMR-WB+</a></li> <li><a href="/wiki/High-Definition_Coding" title="High-Definition Coding">HDC</a></li> <li><a href="/wiki/High-Efficiency_Advanced_Audio_Coding" title="High-Efficiency Advanced Audio Coding">HE-AAC</a></li> <li><a href="/wiki/MPEG-1_Audio_Layer_II" title="MPEG-1 Audio Layer II">MPEG-1 Audio Layer II</a></li> <li><a href="/wiki/Dynamic_Resolution_Adaptation" title="Dynamic Resolution Adaptation">DRA+</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Subcarrier" title="Subcarrier">Subcarrier</a> signals</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Amplitude_modulation_signalling_system" title="Amplitude modulation signalling system">AMSS</a></li> <li><a href="/wiki/DirectBand" title="DirectBand">DirectBand</a></li> <li><a href="/wiki/Program-associated_data" title="Program-associated data">PAD</a></li> <li><a href="/wiki/Radio_Data_System" title="Radio Data System">RDS/RBDS</a></li> <li><a href="/wiki/Subsidiary_communications_authority" title="Subsidiary communications authority">SCA/SCMO</a></li> <li><a href="/wiki/Data_Radio_Channel" title="Data Radio Channel">DARC</a></li></ul> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Related_topics" style="font-size:114%;margin:0 4em">Related topics</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technical (audio)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Audio_data_compression" class="mw-redirect" title="Audio data compression">Audio data compression</a></li> <li><a href="/wiki/Audio_signal_processing" title="Audio signal processing">Audio signal processing</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technical (<a href="/wiki/AM_stereo" title="AM stereo">AM stereo</a> formats)</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/AM_stereo#Belar_System" title="AM stereo">Belar</a></li> <li><a href="/wiki/C-QUAM" title="C-QUAM">C-QUAM</a></li> <li><a href="/wiki/AM_stereo#Harris_System" title="AM stereo">Harris</a></li> <li><a href="/wiki/AM_stereo#Kahn-Hazeltine" title="AM stereo">Kahn-Hazeltine</a></li> <li><a href="/wiki/AM_stereo#Magnavox_System" title="AM stereo">Magnavox</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technical (emission)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/AM_broadcasting" title="AM broadcasting">AM broadcasting</a></li> <li><a href="/wiki/AM_expanded_band" title="AM expanded band">AM expanded band</a></li> <li><a href="/wiki/Cable_radio" title="Cable radio">Cable radio</a></li> <li><a href="/wiki/Digital_radio" title="Digital radio">Digital radio</a></li> <li><a href="/wiki/Error_detection_and_correction" title="Error detection and correction">Error detection and correction</a></li> <li><a href="/wiki/FM_broadcast_band" title="FM broadcast band">FM broadcast band</a></li> <li><a href="/wiki/FM_broadcasting" title="FM broadcasting">FM broadcasting</a></li> <li><a href="/wiki/FM_extended_band_in_Brazil" title="FM extended band in Brazil">FM extended band in Brazil</a></li> <li><a href="/wiki/Multipath_propagation" title="Multipath propagation">Multipath propagation</a></li> <li><a href="/wiki/Shortwave_relay_station" title="Shortwave relay station">Shortwave relay station</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Cultural</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_radio" title="History of radio">History of radio</a></li> <li><a href="/wiki/International_broadcasting" title="International broadcasting">International broadcasting</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><b><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/1/1d/Radio_icon.png" decoding="async" width="32" height="23" class="mw-file-element" data-file-width="30" data-file-height="22" /></span></span> </span><a href="/wiki/Portal:Radio" title="Portal:Radio">Radio portal</a></b></li> <li><a href="/wiki/Comparison_of_radio_systems" title="Comparison of radio systems">Comparison of radio systems</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Time_signal_stations" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Time_signal_stations" title="Template:Time signal stations"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Time_signal_stations" title="Template talk:Time signal stations"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Time_signal_stations" title="Special:EditPage/Template:Time signal stations"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Time_signal_stations" style="font-size:114%;margin:0 4em"><a href="/wiki/Radio_clock" title="Radio clock">Time signal stations</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Longwave" title="Longwave">Longwave</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/BPC_(time_signal)" title="BPC (time signal)">BPC</a></li> <li><a href="/wiki/BPL_(time_service)" title="BPL (time service)">BPL</a></li> <li><a href="/wiki/BSF_(time_service)" title="BSF (time service)">BSF</a></li> <li><a href="/wiki/Beta_(time_signal)" title="Beta (time signal)">Beta</a></li> <li><a href="/wiki/DCF77" title="DCF77">DCF77</a></li> <li><a href="/wiki/JJY" title="JJY">JJY</a></li> <li><a href="/wiki/RBU_(radio_station)" title="RBU (radio station)">RBU</a></li> <li><a href="/wiki/RTZ_(radio_station)" title="RTZ (radio station)">RTZ</a></li> <li><a href="/wiki/ALS162_time_signal" title="ALS162 time signal">TDF time signal</a></li> <li><a href="/wiki/Time_from_NPL_(MSF)" title="Time from NPL (MSF)">Time from NPL</a></li> <li><a href="/wiki/WWVB" title="WWVB">WWVB</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/High_frequency" title="High frequency">Shortwave</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/BPM_(time_service)" title="BPM (time service)">BPM</a></li> <li><a href="/wiki/CHU_(radio_station)" title="CHU (radio station)">CHU</a></li> <li><a href="/wiki/HD2IOA" title="HD2IOA">HD2IOA</a></li> <li><a href="/wiki/HLA_(radio_station)" title="HLA (radio station)">HLA</a></li> <li><a href="/wiki/JN53DV" title="JN53DV">JN53DV</a></li> <li><a href="/wiki/ROA_Time" title="ROA Time">ROA Time</a></li> <li><a href="/wiki/RWM" title="RWM">RWM</a></li> <li><a href="/wiki/WWV_(radio_station)" title="WWV (radio station)">WWV</a></li> <li><a href="/wiki/WWVH" title="WWVH">WWVH</a></li> <li><a href="/wiki/YVTO" title="YVTO">YVTO</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Very-high_frequency" class="mw-redirect" title="Very-high frequency">VHF</a>/<a href="/wiki/FM_band" class="mw-redirect" title="FM band">FM</a>/<a href="/wiki/Ultra-high_frequency" class="mw-redirect" title="Ultra-high frequency">UHF</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Radio_Data_System" title="Radio Data System">Radio Data System</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Satellite_navigation" title="Satellite navigation">Satellite</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/BeiDou" title="BeiDou">BeiDou</a></li> <li><a href="/wiki/DORIS_(satellite_system)" title="DORIS (satellite system)">DORIS</a></li> <li><a href="/wiki/GLONASS" title="GLONASS">GLONASS</a></li> <li><a href="/wiki/Galileo_(satellite_navigation)" title="Galileo (satellite navigation)">Galileo</a></li> <li><a href="/wiki/Global_Positioning_System" title="Global Positioning System">Global Positioning System</a></li> <li><a href="/wiki/Indian_Regional_Navigation_Satellite_System" title="Indian Regional Navigation Satellite System">IRNSS</a></li> <li><a href="/wiki/Quasi-Zenith_Satellite_System" title="Quasi-Zenith Satellite System">Quasi-Zenith Satellite System</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Defunct</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/BSF_(time_service)" title="BSF (time service)">BSF</a></li> <li><a href="/wiki/HBG_(time_signal)" title="HBG (time signal)">HBG</a></li> <li><a href="/wiki/NAA_(Arlington,_Virginia)" title="NAA (Arlington, Virginia)">NAA</a></li> <li><a href="/wiki/OLB5" title="OLB5">OLB5</a></li> <li><a href="/wiki/OMA_(time_signal)" title="OMA (time signal)">OMA</a></li> <li><a href="/wiki/Radio_VNG" title="Radio VNG">Radio VNG</a></li> <li><a href="/wiki/WWVB" title="WWVB">WWVL</a></li> <li><a href="/wiki/Y3S" title="Y3S">Y3S</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Time_measurement_and_standards" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Time_measurement_and_standards" title="Template:Time measurement and standards"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Time_measurement_and_standards" title="Template talk:Time measurement and standards"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Time_measurement_and_standards" title="Special:EditPage/Template:Time measurement and standards"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Time_measurement_and_standards" style="font-size:114%;margin:0 4em"><a href="/wiki/Time" title="Time">Time measurement</a> and <a href="/wiki/Time_standard" title="Time standard">standards</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="3"><div> <ul><li><a href="/wiki/Chronometry" title="Chronometry">Chronometry</a></li> <li><a href="/wiki/Orders_of_magnitude_(time)" title="Orders of magnitude (time)">Orders of magnitude</a></li> <li><a href="/wiki/Time_metrology" class="mw-redirect" title="Time metrology">Metrology</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">International standards</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coordinated_Universal_Time" title="Coordinated Universal Time">Coordinated Universal Time</a> <ul><li><a href="/wiki/UTC_offset" title="UTC offset">offset</a></li></ul></li> <li><a href="/wiki/Universal_Time" title="Universal Time">UT</a></li> <li><a href="/wiki/%CE%94T_(timekeeping)" title="ΔT (timekeeping)">ΔT</a></li> <li><a href="/wiki/DUT1" title="DUT1">DUT1</a></li> <li><a href="/wiki/International_Earth_Rotation_and_Reference_Systems_Service" title="International Earth Rotation and Reference Systems Service">International Earth Rotation and Reference Systems Service</a></li> <li><a href="/wiki/ISO_31-1" title="ISO 31-1">ISO 31-1</a></li> <li><a href="/wiki/ISO_8601" title="ISO 8601">ISO 8601</a></li> <li><a href="/wiki/International_Atomic_Time" title="International Atomic Time">International Atomic Time</a></li> <li><a href="/wiki/12-hour_clock" title="12-hour clock">12-hour clock</a></li> <li><a href="/wiki/24-hour_clock" title="24-hour clock">24-hour clock</a></li> <li><a href="/wiki/Barycentric_Coordinate_Time" title="Barycentric Coordinate Time">Barycentric Coordinate Time</a></li> <li><a href="/wiki/Barycentric_Dynamical_Time" title="Barycentric Dynamical Time">Barycentric Dynamical Time</a></li> <li><a href="/wiki/Civil_time" title="Civil time">Civil time</a></li> <li><a href="/wiki/Daylight_saving_time" title="Daylight saving time">Daylight saving time</a></li> <li><a href="/wiki/Geocentric_Coordinate_Time" title="Geocentric Coordinate Time">Geocentric Coordinate Time</a></li> <li><a href="/wiki/International_Date_Line" title="International Date Line">International Date Line</a></li> <li><a href="/wiki/IERS_Reference_Meridian" title="IERS Reference Meridian">IERS Reference Meridian</a></li> <li><a href="/wiki/Leap_second" title="Leap second">Leap second</a></li> <li><a href="/wiki/Solar_time" title="Solar time">Solar time</a></li> <li><a href="/wiki/Terrestrial_Time" title="Terrestrial Time">Terrestrial Time</a></li> <li><a href="/wiki/Time_zone" title="Time zone">Time zone</a></li> <li><a href="/wiki/180th_meridian" title="180th meridian">180th meridian</a></li></ul> </div></td><td class="noviewer navbox-image" rowspan="9" style="width:1px;padding:0 0 0 2px"><div><span typeof="mw:File"><a href="/wiki/Hourglass" title="Hourglass"><img alt="template illustration" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Marine_sandglass_MMM.jpg/75px-Marine_sandglass_MMM.jpg" decoding="async" width="75" height="175" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Marine_sandglass_MMM.jpg/113px-Marine_sandglass_MMM.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/70/Marine_sandglass_MMM.jpg/150px-Marine_sandglass_MMM.jpg 2x" data-file-width="1637" data-file-height="3819" /></a></span><br /><span typeof="mw:File"><a href="/wiki/Time_zone" title="Time zone"><img alt="template illustration" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Aleutian_Islands_with_180th_meridian_and_International_Date_Line_%28cropped%29.png/75px-Aleutian_Islands_with_180th_meridian_and_International_Date_Line_%28cropped%29.png" decoding="async" width="75" height="152" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Aleutian_Islands_with_180th_meridian_and_International_Date_Line_%28cropped%29.png/113px-Aleutian_Islands_with_180th_meridian_and_International_Date_Line_%28cropped%29.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Aleutian_Islands_with_180th_meridian_and_International_Date_Line_%28cropped%29.png/150px-Aleutian_Islands_with_180th_meridian_and_International_Date_Line_%28cropped%29.png 2x" data-file-width="496" data-file-height="1007" /></a></span></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Obsolete standards</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ephemeris_time" title="Ephemeris time">Ephemeris time</a></li> <li><a href="/wiki/Greenwich_Mean_Time" title="Greenwich Mean Time">Greenwich Mean Time</a></li> <li><a href="/wiki/Prime_meridian" title="Prime meridian">Prime meridian</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Time_in_physics" title="Time in physics">Time in physics</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Absolute_space_and_time" title="Absolute space and time">Absolute space and time</a></li> <li><a href="/wiki/Spacetime" title="Spacetime">Spacetime</a></li> <li><a href="/wiki/Chronon" title="Chronon">Chronon</a></li> <li><a href="/wiki/Continuous_signal" class="mw-redirect" title="Continuous signal">Continuous signal</a></li> <li><a href="/wiki/Coordinate_time" title="Coordinate time">Coordinate time</a></li> <li><a href="/wiki/Cosmological_decade" title="Cosmological decade">Cosmological decade</a></li> <li><a href="/wiki/Discrete_time_and_continuous_time" title="Discrete time and continuous time">Discrete time and continuous time</a></li> <li><a href="/wiki/Proper_time" title="Proper time">Proper time</a></li> <li><a href="/wiki/Theory_of_relativity" title="Theory of relativity">Theory of relativity</a></li> <li><a href="/wiki/Time_dilation" title="Time dilation">Time dilation</a></li> <li><a href="/wiki/Gravitational_time_dilation" title="Gravitational time dilation">Gravitational time dilation</a></li> <li><a href="/wiki/Time_domain" title="Time domain">Time domain</a></li> <li><a href="/wiki/Time-translation_symmetry" title="Time-translation symmetry">Time-translation symmetry</a></li> <li><a href="/wiki/T-symmetry" title="T-symmetry">T-symmetry</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Horology" class="mw-redirect" title="Horology">Horology</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Clock" title="Clock">Clock</a></li> <li><a href="/wiki/Astrarium" title="Astrarium">Astrarium</a></li> <li><a href="/wiki/Atomic_clock" title="Atomic clock">Atomic clock</a></li> <li><a href="/wiki/Complication_(horology)" title="Complication (horology)">Complication</a></li> <li><a href="/wiki/History_of_timekeeping_devices" title="History of timekeeping devices">History of timekeeping devices</a></li> <li><a href="/wiki/Hourglass" title="Hourglass">Hourglass</a></li> <li><a href="/wiki/Marine_chronometer" title="Marine chronometer">Marine chronometer</a></li> <li><a href="/wiki/Marine_sandglass" title="Marine sandglass">Marine sandglass</a></li> <li><a href="/wiki/Radio_clock" title="Radio clock">Radio clock</a></li> <li><a href="/wiki/Watch" title="Watch">Watch</a> <ul><li><a href="/wiki/Stopwatch" title="Stopwatch">stopwatch</a></li></ul></li> <li><a href="/wiki/Water_clock" title="Water clock">Water clock</a></li> <li><a href="/wiki/Sundial" title="Sundial">Sundial</a></li> <li><a href="/wiki/Dialing_scales" title="Dialing scales">Dialing scales</a></li> <li><a href="/wiki/Equation_of_time" title="Equation of time">Equation of time</a></li> <li><a href="/wiki/History_of_sundials" title="History of sundials">History of sundials</a></li> <li><a href="/wiki/Schema_for_horizontal_dials" title="Schema for horizontal dials">Sundial markup schema</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Calendar" title="Calendar">Calendar</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Gregorian_calendar" title="Gregorian calendar">Gregorian</a></li> <li><a href="/wiki/Hebrew_calendar" title="Hebrew calendar">Hebrew</a></li> <li><a href="/wiki/Hindu_calendar" title="Hindu calendar">Hindu</a></li> <li><a href="/wiki/Holocene_calendar" title="Holocene calendar">Holocene</a></li> <li><a href="/wiki/Islamic_calendar" title="Islamic calendar">Islamic</a> (lunar Hijri)</li> <li><a href="/wiki/Julian_calendar" title="Julian calendar">Julian</a></li> <li><a href="/wiki/Solar_Hijri_calendar" title="Solar Hijri calendar">Solar Hijri</a></li> <li><a href="/wiki/Astronomical_year_numbering" title="Astronomical year numbering">Astronomical</a></li> <li><a href="/wiki/Dominical_letter" title="Dominical letter">Dominical letter</a></li> <li><a href="/wiki/Epact" title="Epact">Epact</a></li> <li><a href="/wiki/Equinox" title="Equinox">Equinox</a></li> <li><a href="/wiki/Intercalation_(timekeeping)" title="Intercalation (timekeeping)">Intercalation</a></li> <li><a href="/wiki/Julian_day" title="Julian day">Julian day</a></li> <li><a href="/wiki/Leap_year" title="Leap year">Leap year</a></li> <li><a href="/wiki/Lunar_calendar" title="Lunar calendar">Lunar</a></li> <li><a href="/wiki/Lunisolar_calendar" title="Lunisolar calendar">Lunisolar</a></li> <li><a href="/wiki/Solar_calendar" title="Solar calendar">Solar</a></li> <li><a href="/wiki/Solstice" title="Solstice">Solstice</a></li> <li><a href="/wiki/Tropical_year" title="Tropical year">Tropical year</a></li> <li><a href="/wiki/Determination_of_the_day_of_the_week" title="Determination of the day of the week">Weekday determination</a></li> <li><a href="/wiki/Names_of_the_days_of_the_week" title="Names of the days of the week">Weekday names</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Archaeology and geology</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Chronological_dating" title="Chronological dating">Chronological dating</a></li> <li><a href="/wiki/Geologic_time_scale" title="Geologic time scale">Geologic time scale</a></li> <li><a href="/wiki/International_Commission_on_Stratigraphy" title="International Commission on Stratigraphy">International Commission on Stratigraphy</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Astronomical_chronology" title="Astronomical chronology">Astronomical chronology</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Galactic_year" title="Galactic year">Galactic year</a></li> <li><a href="/wiki/Nuclear_timescale" title="Nuclear timescale">Nuclear timescale</a></li> <li><a href="/wiki/Precession" title="Precession">Precession</a></li> <li><a href="/wiki/Sidereal_time" title="Sidereal time">Sidereal time</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other <a href="/wiki/Unit_of_time" title="Unit of time">units of time</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Instant" title="Instant">Instant</a></li> <li><a href="/wiki/Flick_(time)" title="Flick (time)">Flick</a></li> <li><a href="/wiki/Shake_(unit)" title="Shake (unit)">Shake</a></li> <li><a href="/wiki/Jiffy_(time)" title="Jiffy (time)">Jiffy</a></li> <li><a href="/wiki/Second" title="Second">Second</a></li> <li><a href="/wiki/Minute" title="Minute">Minute</a></li> <li><a href="/wiki/Moment_(unit)" title="Moment (unit)">Moment</a></li> <li><a href="/wiki/Hour" title="Hour">Hour</a></li> <li><a href="/wiki/Day" title="Day">Day</a></li> <li><a href="/wiki/Week" title="Week">Week</a></li> <li><a href="/wiki/Fortnight" title="Fortnight">Fortnight</a></li> <li><a href="/wiki/Month" title="Month">Month</a></li> <li><a href="/wiki/Year" title="Year">Year</a></li> <li><a href="/wiki/Olympiad" title="Olympiad">Olympiad</a></li> <li><a href="/wiki/Lustrum" title="Lustrum">Lustrum</a></li> <li><a href="/wiki/Decade" title="Decade">Decade</a></li> <li><a href="/wiki/Century" title="Century">Century</a></li> <li><a href="/wiki/Saeculum" title="Saeculum">Saeculum</a></li> <li><a href="/wiki/Millennium" title="Millennium">Millennium</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related topics</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Chronology" title="Chronology">Chronology</a></li> <li><a href="/wiki/Duration_(philosophy)" title="Duration (philosophy)">Duration</a> <ul><li><a href="/wiki/Duration_(music)" title="Duration (music)">music</a></li></ul></li> <li><a href="/wiki/Mental_chronometry" title="Mental chronometry">Mental chronometry</a></li> <li><a href="/wiki/Decimal_time" title="Decimal time">Decimal time</a></li> <li><a href="/wiki/Metric_time" title="Metric time">Metric time</a></li> <li><a href="/wiki/System_time" title="System time">System time</a></li> <li><a href="/wiki/Time_metrology" class="mw-redirect" title="Time metrology">Time metrology</a></li> <li><a href="/wiki/Time_value_of_money" title="Time value of money">Time value of money</a></li> <li><a href="/wiki/Timekeeper" title="Timekeeper">Timekeeper</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"></div><div role="navigation" class="navbox" aria-labelledby="Time" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Time_topics" title="Template:Time topics"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Time_topics" title="Template talk:Time topics"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Time_topics" title="Special:EditPage/Template:Time topics"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Time" style="font-size:114%;margin:0 4em"><a href="/wiki/Time" title="Time">Time</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Key concepts</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Past" title="Past">Past</a></li> <li><a href="/wiki/Present" title="Present">Present</a></li> <li><a href="/wiki/Future" title="Future">Future</a></li> <li><a href="/wiki/Eternity" title="Eternity">Eternity</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Horology" class="mw-redirect" title="Horology">Measurement</a><br />and <a href="/wiki/Time_standard" title="Time standard">standards</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;"><a href="/wiki/Chronometry" title="Chronometry">Chronometry</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coordinated_Universal_Time" title="Coordinated Universal Time">UTC</a></li> <li><a href="/wiki/Universal_Time" title="Universal Time">UT</a></li> <li><a href="/wiki/International_Atomic_Time" title="International Atomic Time">TAI</a></li> <li><a href="/wiki/Unit_of_time" title="Unit of time">Unit of time</a></li> <li><a href="/wiki/Orders_of_magnitude_(time)" title="Orders of magnitude (time)">Orders of magnitude (time)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;"><a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">Measurement<br />systems</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Italian_six-hour_clock" title="Italian six-hour clock">Italian six-hour clock</a></li> <li><a href="/wiki/Thai_six-hour_clock" title="Thai six-hour clock">Thai six-hour clock</a></li> <li><a href="/wiki/12-hour_clock" title="12-hour clock">12-hour clock</a></li> <li><a href="/wiki/24-hour_clock" title="24-hour clock">24-hour clock</a></li> <li><a href="/wiki/Relative_hour" title="Relative hour">Relative hour</a></li> <li><a href="/wiki/Daylight_saving_time" title="Daylight saving time">Daylight saving time</a></li> <li><a href="/wiki/Traditional_Chinese_timekeeping" title="Traditional Chinese timekeeping">Chinese</a></li> <li><a href="/wiki/Decimal_time" title="Decimal time">Decimal</a></li> <li><a href="/wiki/Hexadecimal_time" title="Hexadecimal time">Hexadecimal</a></li> <li><a href="/wiki/Hindu_units_of_time" title="Hindu units of time">Hindu</a></li> <li><a href="/wiki/Metric_time" title="Metric time">Metric</a></li> <li><a href="/wiki/Roman_timekeeping" title="Roman timekeeping">Roman</a></li> <li><a href="/wiki/Sidereal_time" title="Sidereal time">Sidereal</a></li> <li><a href="/wiki/Solar_time" title="Solar time">Solar</a></li> <li><a href="/wiki/Time_zone" title="Time zone">Time zone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;"><a href="/wiki/Calendar" title="Calendar">Calendars</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Calendar#Systems" title="Calendar">Main types</a> <ul><li><a href="/wiki/Solar_calendar" title="Solar calendar">Solar</a></li> <li><a href="/wiki/Lunar_calendar" title="Lunar calendar">Lunar</a></li> <li><a href="/wiki/Lunisolar_calendar" title="Lunisolar calendar">Lunisolar</a></li></ul></li> <li><a href="/wiki/Gregorian_calendar" title="Gregorian calendar">Gregorian</a></li> <li><a href="/wiki/Julian_calendar" title="Julian calendar">Julian</a></li> <li><a href="/wiki/Hebrew_calendar" title="Hebrew calendar">Hebrew</a></li> <li><a href="/wiki/Islamic_calendar" title="Islamic calendar">Islamic</a></li> <li><a href="/wiki/Solar_Hijri_calendar" title="Solar Hijri calendar">Solar Hijri</a></li> <li><a href="/wiki/Chinese_calendar" title="Chinese calendar">Chinese</a></li> <li><a href="/wiki/Hindu_calendar" title="Hindu calendar">Hindu Panchang</a></li> <li><a href="/wiki/Maya_calendar" title="Maya calendar">Maya</a></li> <li><i><a href="/wiki/List_of_calendars" title="List of calendars">List</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;"><a href="/wiki/Clock" title="Clock">Clocks</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Clock#Types" title="Clock">Main types</a> <ul><li><a href="/wiki/Astronomical_clock" title="Astronomical clock">astronomical</a> <ul><li><a href="/wiki/Astrarium" title="Astrarium">astrarium</a></li></ul></li> <li><a href="/wiki/Atomic_clock" title="Atomic clock">atomic</a> <ul><li><a href="/wiki/Quantum_clock" class="mw-redirect" title="Quantum clock">quantum</a></li></ul></li> <li><a href="/wiki/Hourglass" title="Hourglass">hourglass</a></li> <li><a href="/wiki/Marine_chronometer" title="Marine chronometer">marine</a></li> <li><a href="/wiki/Sundial" title="Sundial">sundial</a></li> <li><a href="/wiki/Watch" title="Watch">watch</a> <ul><li><a href="/wiki/Mechanical_watch" title="Mechanical watch">mechanical</a></li> <li><a href="/wiki/Stopwatch" title="Stopwatch">stopwatch</a></li></ul></li> <li><a href="/wiki/Water_clock" title="Water clock">water-based</a></li></ul></li> <li><a href="/wiki/Cuckoo_clock" title="Cuckoo clock">Cuckoo clock</a></li> <li><a href="/wiki/Digital_clock" title="Digital clock">Digital clock</a></li> <li><a href="/wiki/Grandfather_clock" title="Grandfather clock">Grandfather clock</a></li> <li><i><a href="/wiki/History_of_timekeeping_devices" title="History of timekeeping devices">History</a></i> <ul><li><i><a href="/wiki/Timeline_of_time_measurement_inventions" title="Timeline of time measurement inventions">Timeline</a></i></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div class="hlist"><ul><li><a href="/wiki/Chronology" title="Chronology">Chronology</a></li><li><a href="/wiki/History" title="History">History</a></li></ul></div></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Astronomical_chronology" title="Astronomical chronology">Astronomical chronology</a></li> <li><a href="/wiki/Big_History" title="Big History">Big History</a></li> <li><a href="/wiki/Calendar_era" title="Calendar era">Calendar era</a></li> <li><a href="/wiki/Deep_time" title="Deep time">Deep time</a></li> <li><a href="/wiki/Periodization" title="Periodization">Periodization</a></li> <li><a href="/wiki/Regnal_year" title="Regnal year">Regnal year</a></li> <li><a href="/wiki/Timeline" title="Timeline">Timeline</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Philosophy_of_space_and_time" title="Philosophy of space and time">Philosophy of time</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/A_series_and_B_series" title="A series and B series">A series and B series</a></li> <li><a href="/wiki/B-theory_of_time" title="B-theory of time">B-theory of time</a></li> <li><a href="/wiki/Chronocentrism" title="Chronocentrism">Chronocentrism</a></li> <li><a href="/wiki/Duration_(philosophy)" title="Duration (philosophy)">Duration</a></li> <li><a href="/wiki/Endurantism" title="Endurantism">Endurantism</a></li> <li><a href="/wiki/Eternal_return" title="Eternal return">Eternal return</a></li> <li><a href="/wiki/Eternalism_(philosophy_of_time)" title="Eternalism (philosophy of time)">Eternalism</a></li> <li><a href="/wiki/Event_(philosophy)" title="Event (philosophy)">Event</a></li> <li><a href="/wiki/Perdurantism" title="Perdurantism">Perdurantism</a></li> <li><a href="/wiki/Philosophical_presentism" title="Philosophical presentism">Presentism</a></li> <li><a href="/wiki/Temporal_finitism" title="Temporal finitism">Temporal finitism</a></li> <li><a href="/wiki/Temporal_parts" title="Temporal parts">Temporal parts</a></li> <li><i><a href="/wiki/The_Unreality_of_Time" title="The Unreality of Time">The Unreality of Time</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div class="hlist"><ul><li><a href="/wiki/Category:Time_in_religion" title="Category:Time in religion">Religion</a></li><li><a href="/wiki/Template:Time_in_religion_and_mythology" title="Template:Time in religion and mythology">Mythology</a></li></ul></div></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ages_of_Man" title="Ages of Man">Ages of Man</a></li> <li><a href="/wiki/Destiny" title="Destiny">Destiny</a></li> <li><a href="/wiki/Immortality" title="Immortality">Immortality</a></li> <li><a href="/wiki/The_Dreaming" title="The Dreaming">Dreamtime</a></li> <li><a href="/wiki/K%C4%81la" title="Kāla">Kāla</a></li> <li><a href="/wiki/Time_and_fate_deities" title="Time and fate deities">Time and fate deities</a> <ul><li><a href="/wiki/Father_Time" title="Father Time">Father Time</a></li></ul></li> <li><a href="/wiki/Wheel_of_time" title="Wheel of time">Wheel of time</a> <ul><li><a href="/wiki/Kalachakra" title="Kalachakra">Kalachakra</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Time_perception" title="Time perception">Human experience</a><br />and <a href="/wiki/Time-use_research" title="Time-use research">use of time</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Chronemics" title="Chronemics">Chronemics</a></li> <li><a href="/wiki/Generation_time" title="Generation time">Generation time</a></li> <li><a href="/wiki/Mental_chronometry" title="Mental chronometry">Mental chronometry</a></li> <li><a href="/wiki/Duration_(music)" title="Duration (music)">Music</a> <ul><li><a href="/wiki/Tempo" title="Tempo">tempo</a></li> <li><a href="/wiki/Time_signature" title="Time signature">time signature</a></li></ul></li> <li><a href="/wiki/Rosy_retrospection" title="Rosy retrospection">Rosy retrospection</a></li> <li><a href="/wiki/Tense%E2%80%93aspect%E2%80%93mood" title="Tense–aspect–mood">Tense–aspect–mood</a></li> <li><a href="/wiki/Time_management" title="Time management">Time management</a></li> <li><a href="/wiki/Yesterday_(time)" title="Yesterday (time)">Yesterday</a> – <a href="/wiki/Present" title="Present">Today</a> – <a href="/wiki/Tomorrow_(time)" title="Tomorrow (time)">Tomorrow</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Time in <a href="/wiki/Science" title="Science">science</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;"><a href="/wiki/Geology" title="Geology">Geology</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Geologic_time_scale" title="Geologic time scale">Geological time</a> <ul><li><a href="/wiki/Age_(geology)" class="mw-redirect" title="Age (geology)">age</a></li> <li><a href="/wiki/Chronozone" title="Chronozone">chron</a></li> <li><a href="/wiki/Eon_(geology)" class="mw-redirect" title="Eon (geology)">eon</a></li> <li><a href="/wiki/Epoch_(geology)" class="mw-redirect" title="Epoch (geology)">epoch</a></li> <li><a href="/wiki/Era_(geology)" class="mw-redirect" title="Era (geology)">era</a></li> <li><a href="/wiki/Geological_period" class="mw-redirect" title="Geological period">period</a></li></ul></li> <li><a href="/wiki/Geochronology" title="Geochronology">Geochronology</a></li> <li><a href="/wiki/Geological_history_of_Earth" title="Geological history of Earth">Geological history of Earth</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;"><a href="/wiki/Time_in_physics" title="Time in physics">Physics</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Absolute_space_and_time" title="Absolute space and time">Absolute space and time</a></li> <li><a href="/wiki/Arrow_of_time" title="Arrow of time">Arrow of time</a></li> <li><a href="/wiki/Chronon" title="Chronon">Chronon</a></li> <li><a href="/wiki/Coordinate_time" title="Coordinate time">Coordinate time</a></li> <li><a href="/wiki/Instant" title="Instant">Instant</a></li> <li><a href="/wiki/Proper_time" title="Proper time">Proper time</a></li> <li><a href="/wiki/Spacetime" title="Spacetime">Spacetime</a></li> <li><a href="/wiki/Theory_of_relativity" title="Theory of relativity">Theory of relativity</a></li> <li><a href="/wiki/Time_domain" title="Time domain">Time domain</a></li> <li><a href="/wiki/Time_translation_symmetry" class="mw-redirect" title="Time translation symmetry">Time translation symmetry</a></li> <li><a href="/wiki/T-symmetry" title="T-symmetry">Time reversal symmetry</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6.5em;font-weight:normal; text-align:center;">Other fields</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Chronological_dating" title="Chronological dating">Chronological dating</a></li> <li><a href="/wiki/Chronobiology" title="Chronobiology">Chronobiology</a> <ul><li><a href="/wiki/Circadian_rhythm" title="Circadian rhythm">Circadian rhythms</a></li></ul></li> <li><a href="/wiki/Chemical_clock" title="Chemical clock">Clock reaction</a></li> <li><a href="/wiki/Glottochronology" title="Glottochronology">Glottochronology</a></li> <li><a href="/wiki/Time_geography" title="Time geography">Time geography</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Leap_year" title="Leap year">Leap year</a></li> <li><a href="/wiki/Memory" title="Memory">Memory</a></li> <li><a href="/wiki/Moment_(unit)" title="Moment (unit)">Moment</a></li> <li><a href="/wiki/Space" title="Space">Space</a></li> <li><a href="/wiki/System_time" title="System time">System time</a></li> <li><i><a href="/wiki/Tempus_fugit" title="Tempus fugit">Tempus fugit</a></i></li> <li><a href="/wiki/Time_capsule" title="Time capsule">Time capsule</a></li> <li><a href="/wiki/Time_immemorial" title="Time immemorial">Time immemorial</a></li> <li><a href="/wiki/Time_travel" title="Time travel">Time travel</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Time" title="Category:Time">Category</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" 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