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<li id="toc-Service_improvement_plans" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Service_improvement_plans"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Service improvement plans</span> </div> </a> <ul id="toc-Service_improvement_plans-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Antennas" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Antennas"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Antennas</span> </div> </a> <ul id="toc-Antennas-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Modulation_format" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Modulation_format"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Modulation format</span> </div> </a> <button aria-controls="toc-Modulation_format-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 Modulation format subsection</span> </button> <ul id="toc-Modulation_format-sublist" class="vector-toc-list"> <li id="toc-Amplitude_modulation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Amplitude_modulation"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Amplitude modulation</span> </div> </a> <ul id="toc-Amplitude_modulation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Phase_modulation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Phase_modulation"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Phase modulation</span> </div> </a> <ul id="toc-Phase_modulation-sublist" class="vector-toc-list"> <li id="toc-Allowance_for_carrier_phase_tracking_receivers" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Allowance_for_carrier_phase_tracking_receivers"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2.1</span> <span>Allowance for carrier phase tracking receivers</span> </div> </a> <ul id="toc-Allowance_for_carrier_phase_tracking_receivers-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Station_ID" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Station_ID"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Station ID</span> </div> </a> <ul id="toc-Station_ID-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Amplitude-modulated_time_code" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Amplitude-modulated_time_code"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Amplitude-modulated time code</span> </div> </a> <button aria-controls="toc-Amplitude-modulated_time_code-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 Amplitude-modulated time code subsection</span> </button> <ul id="toc-Amplitude-modulated_time_code-sublist" class="vector-toc-list"> <li id="toc-Announcement_bits" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Announcement_bits"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Announcement bits</span> </div> </a> <ul id="toc-Announcement_bits-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Phase_modulated_time_code" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Phase_modulated_time_code"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Phase modulated time code</span> </div> </a> <button aria-controls="toc-Phase_modulated_time_code-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 Phase modulated time code subsection</span> </button> <ul id="toc-Phase_modulated_time_code-sublist" class="vector-toc-list"> <li id="toc-One-minute_time_frames" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#One-minute_time_frames"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>One-minute time frames</span> </div> </a> <ul id="toc-One-minute_time_frames-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Announcement_bits_2" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Announcement_bits_2"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Announcement bits</span> </div> </a> <ul id="toc-Announcement_bits_2-sublist" class="vector-toc-list"> <li id="toc-DST_and_leap_second_warning" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#DST_and_leap_second_warning"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2.1</span> <span>DST and leap second warning</span> </div> </a> <ul id="toc-DST_and_leap_second_warning-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-DST_schedule" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#DST_schedule"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2.2</span> <span>DST schedule</span> </div> </a> <ul id="toc-DST_schedule-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Message_frames" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Message_frames"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.3</span> <span>Message frames</span> </div> </a> <ul id="toc-Message_frames-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Six-minute_time_frames" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Six-minute_time_frames"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.4</span> <span>Six-minute time frames</span> </div> </a> <ul id="toc-Six-minute_time_frames-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Propagation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Propagation"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Propagation</span> </div> </a> <ul id="toc-Propagation-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">7</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">8</span> <span>References</span> </div> </a> <ul id="toc-References-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">9</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" 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class="firstHeading mw-first-heading"><span class="mw-page-title-main">WWVB</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. 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mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AF%D8%A8%D9%84%DB%8C%D9%88_%D8%AF%D8%A8%D9%84%DB%8C%D9%88_%D9%88%DB%8C_%D8%A8%DB%8C" title="دبلیو دبلیو وی بی – Persian" lang="fa" hreflang="fa" data-title="دبلیو دبلیو وی بی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/WWVB" title="WWVB – Japanese" lang="ja" hreflang="ja" data-title="WWVB" 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-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/WWVB" title="WWVB – Chinese" lang="zh" hreflang="zh" data-title="WWVB" 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 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href="https://geohack.toolforge.org/geohack.php?pagename=WWVB&params=40_40_41_N_105_2_49_W_region:US-CO_type:landmark_dim:1430&title=WWVB+-+Transmitter+building"><span class="geo-default"><span class="geo-dms" title="Maps, aerial photos, and other data for this location"><span class="latitude">40°40′41″N</span> <span class="longitude">105°2′49″W</span></span></span><span class="geo-multi-punct"> / </span><span class="geo-nondefault"><span class="vcard"><span class="geo-dec" title="Maps, aerial photos, and other data for this location">40.67806°N 105.04694°W</span><span style="display:none"> / <span class="geo">40.67806; -105.04694</span></span><span style="display:none"> (<span class="fn org">WWVB - Transmitter building</span>)</span></span></span></a></span></span></div></div> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">American longwave time signal radio station</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 vcard"><caption class="infobox-title fn org">NIST Time & Frequency Service</caption><tbody><tr><th scope="row" class="infobox-label">Type</th><td class="infobox-data category"><a href="/wiki/Radio_clock" title="Radio clock">Time station</a></td></tr><tr><th scope="row" class="infobox-label">Country</th><td class="infobox-data adr"><div style="display:inline;" class="country-name">United States</div></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #efefef; color: #202122;">Ownership</th></tr><tr><th scope="row" class="infobox-label">Owner</th><td class="infobox-data"><a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Institute of Standards and Technology</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #efefef; color: #202122;">History</th></tr><tr><th scope="row" class="infobox-label">Launch date</th><td class="infobox-data">July <a href="/wiki/1956_in_radio" title="1956 in radio">1956</a> (under experimental license KK2XEI)<br />July 4, <a href="/wiki/1963_in_radio" title="1963 in radio">1963</a> (as WWVB)</td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #efefef; color: #202122;">Coverage</th></tr><tr><th scope="row" class="infobox-label">Availability</th><td class="infobox-data">Canada, United States, <a href="/wiki/Mexico" title="Mexico">Mexico</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #efefef; color: #202122;">Links</th></tr><tr><th scope="row" class="infobox-label">Website</th><td class="infobox-data"><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 journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/div688/grp40/wwvb.cfm">"WWVB home page"</a>. <i>NIST</i>. March 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NIST&rft.atitle=WWVB+home+page&rft.date=2010-03&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fdiv688%2Fgrp40%2Fwwvb.cfm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></td></tr></tbody></table> <p><b>WWVB</b> is a <a href="/wiki/Longwave" title="Longwave">longwave</a> <a href="/wiki/Time_signal" title="Time signal">time signal</a> radio station near <a href="/wiki/Fort_Collins,_Colorado" title="Fort Collins, Colorado">Fort Collins, Colorado</a>, and is operated by the <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Institute of Standards and Technology</a> (NIST).<sup id="cite_ref-homepage_1-0" class="reference"><a href="#cite_note-homepage-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Most <a href="/wiki/Radio_clock" title="Radio clock">radio-controlled clocks</a> in North America<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> use WWVB's transmissions to set the correct time. </p><p>The normal signal transmitted from WWVB is 70 kW <a href="/wiki/Effective_radiated_power" title="Effective radiated power">ERP</a> and uses a 60 <a href="/wiki/Hertz" title="Hertz">kHz</a> <a href="/wiki/Carrier_wave" title="Carrier wave">carrier wave</a> yielding a <a href="/wiki/Frequency" title="Frequency">frequency</a> uncertainty of less than 1 part in 10<sup>12</sup>. The <a href="/wiki/Time_code" class="mw-redirect" title="Time code">time code</a> signal is derived from a set of <a href="/wiki/Atomic_clock" title="Atomic clock">atomic clocks</a> located at the site, and transmitted using the <a href="/wiki/IRIG_timecode" title="IRIG timecode">IRIG "H"</a> format and modulated onto the carrier wave using <a href="/wiki/Pulse-width_modulation" title="Pulse-width modulation">pulse-width modulation</a> and <a href="/wiki/Amplitude-shift_keying" title="Amplitude-shift keying">amplitude-shift keying</a> at one <a href="/wiki/Bit_per_second" class="mw-redirect" title="Bit per second">bit per second</a>. A single complete frame of time code begins at the start of each minute, lasts one minute, and conveys the year, day of year, hour, minute, and other information as of the beginning of the minute. </p><p>WWVB is co-located with <a href="/wiki/WWV_(radio_station)" title="WWV (radio station)">WWV</a>, a time signal station that broadcasts in both voice and time code on multiple <a href="/wiki/Shortwave_radio" title="Shortwave radio">shortwave radio</a> frequencies. WWVB is not an acronym or abbreviation but a <a href="/wiki/Call_sign" title="Call sign">call sign</a> for the radio station. </p><p>While most time signals encode the local time of the broadcasting nation, the United States spans multiple <a href="/wiki/Time_zone" title="Time zone">time zones</a>, so WWVB broadcasts the time in <a href="/wiki/Coordinated_Universal_Time" title="Coordinated Universal Time">Coordinated Universal Time (UTC)</a>. Radio-controlled clocks can then apply time zone and <a href="/wiki/Daylight_saving_time" title="Daylight saving time">daylight saving time</a> offsets as needed to display local time.<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> The time used in the broadcast is set by the NIST Time Scale, known as UTC(NIST). This time scale is the calculated average time of an ensemble of master clocks, themselves calibrated by the <a href="/wiki/NIST-F1" title="NIST-F1">NIST-F1</a> and <a href="/wiki/NIST-F2" title="NIST-F2">NIST-F2</a> <a href="/wiki/Atomic_fountain" title="Atomic fountain">cesium fountain</a> <a href="/wiki/Atomic_clock" title="Atomic clock">atomic clocks</a>.<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> </p><p>In 2011, NIST estimated the number of <a href="/wiki/Radio_clock" title="Radio clock">radio clocks</a> and <a href="/wiki/Watch#Electronic_movement" title="Watch">wristwatches</a> equipped with a WWVB receiver at over 50 million.<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>WWVB, along with NIST's shortwave time code-and-announcement stations WWV and WWVH, were proposed for defunding and elimination in the 2019 NIST budget.<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> However, the final 2019 NIST budget preserved funding for the three stations.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p>At midnight on April 7, 2024, WWVB's south antenna was disabled due to damage sustained during high winds. WWVB then transmitted exclusively from the north antenna, at a reduced power of 30kW. On May 20, 2024, NIST announced that the necessary replacement parts were being manufactured and shipped, with expected service restoration at the end of September 2024. As of October 10, 2024, WWVB was back to operating at full power.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable" style="text-align:center;"> <caption>NIST Time Signal Station Services<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </caption> <tbody><tr> <th>Station </th> <th>Year<br />in service </th> <th>Year out<br />of service </th> <th>Radio<br />frequencies </th> <th>Audio<br />frequencies </th> <th>Musical<br />pitch </th> <th>Time<br />intervals </th> <th>Time<br />signals </th> <th>UT2<br />correction </th> <th>Propagation<br />forecasts </th> <th>Geophysical<br />alerts </th></tr> <tr> <td><a href="/wiki/WWV_(radio_station)" title="WWV (radio station)">WWV</a> </td> <td>1923 </td> <td rowspan="3"> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td></tr> <tr> <td><a href="/wiki/WWVH" title="WWVH">WWVH</a> </td> <td>1948 </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td> </td> <td><b>✔</b> </td></tr> <tr> <td>WWVB </td> <td>1963 </td> <td><b>✔</b> </td> <td> </td> <td> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td><b>✔</b> </td> <td> </td> <td> </td></tr> <tr> <td>WWVL </td> <td>1963 </td> <td>1972 </td> <td><b>✔</b> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td></tr></tbody></table> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=1" title="Edit section: History"><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-More_citations_needed_section plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/60px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/120px-Question_book-new.svg.png 1.5x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This section <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/WWVB" title="Special:EditPage/WWVB">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a> in this section. Unsourced material may be challenged and removed.</span> <span class="date-container"><i>(<span class="date">November 2020</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p><a href="/wiki/Low_frequency" title="Low frequency">LF</a> and <a href="/wiki/Very_low_frequency" title="Very low frequency">VLF</a> (very low frequency) broadcasts have long been used to distribute time and frequency standards. As early as 1904, the <a href="/wiki/United_States_Naval_Observatory" title="United States Naval Observatory">United States Naval Observatory</a> (USNO) was broadcasting time signals from the city of Boston as an aid to navigation. This experiment and others like it made it evident that LF and VLF signals could cover a large area using a relatively low power. By 1923, NIST radio station WWV had begun broadcasting standard carrier signals to the public on frequencies ranging from 75 to 2,000 kHz. </p><p>These signals were used to calibrate radio equipment, which became increasingly important as more and more stations became operational. Over the years, many radio navigation systems were designed using stable time and frequency signals broadcast on the LF and VLF bands. The best known of these navigation systems was the now-obsolete <a href="/wiki/Loran-C" title="Loran-C">Loran-C</a>, which allowed ships and planes to navigate via reception of 100 kHz signals broadcast from multiple transmitters. </p><p>What is now WWVB began as radio station KK2XEI in July 1956. The transmitter was located in <a href="/wiki/Boulder,_Colorado" title="Boulder, Colorado">Boulder, Colorado</a>, and the <a href="/wiki/Effective_radiated_power" title="Effective radiated power">effective radiated power</a> (ERP) was just 1.4 watts. Even so, the signal was able to be monitored at <a href="/wiki/Harvard_University" title="Harvard University">Harvard University</a> in <a href="/wiki/Massachusetts" title="Massachusetts">Massachusetts</a>. The purpose of this experimental transmission was to show that the radio path was stable and the frequency error was small at low frequencies. </p><p>In 1962, the National Bureau of Standards (NBS) — now known as <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Institute of Standards and Technology</a> (NIST) — began building a new facility at a site near Fort Collins, Colorado. This site became the home of WWVB and WWVL, a 20 kHz station that was moved from the mountains west of Boulder. </p><p>The site was attractive for several reasons, one being its exceptionally high ground conductivity, which was due to the high alkalinity of the soil. It was also reasonably close to Boulder (about 50 miles or 80 kilometres), which made it easy to staff and manage, but much farther away from the mountains, which made it a better choice for broadcasting an omnidirectional signal. </p><p>WWVB went on the air on July 4, 1963 (July 5 at 00:00 UTC),<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> broadcasting a 5 kW ERP signal on 60 kHz. WWVL began transmitting a 0.5 kW ERP signal on 20 kHz the following month, using <a href="/wiki/Frequency-shift_keying" title="Frequency-shift keying">frequency-shift keying</a>, shifting from 20 kHz to 26 kHz, to send data. The WWVL broadcast was discontinued in July 1972, while WWVB became a permanent part of the nation's infrastructure. </p><p>A time code was added to WWVB on July 1, 1965. This made it possible for clocks to be designed that could receive the signal, decode it, and then automatically synchronize themselves. The time code format has changed only slightly since 1965; it sends a decimal time code, using four binary bits to send each digit in <a href="/wiki/Binary-coded_decimal" title="Binary-coded decimal">binary-coded decimal</a> (BCD). </p><p>The ERP of WWVB has been increased several times. It was raised to 7 kW and then 13 kW ERP early in its life and remained so for many years. As part of a WWVB modernization program in the late 1990s, the decommissioned WWVL antenna was refurbished and incorporated into the current phased array. Using both antennas simultaneously resulted in an increase until a major upgrade during 1998 boosted the ERP to 50 kW in 1999, and finally to 70 kW in 2005. The station also became able to operate on one antenna, with an ERP of 27 kW, while engineers could carry out maintenance on the other.<sup id="cite_ref-Oldtimer_11-0" class="reference"><a href="#cite_note-Oldtimer-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p><p>The power increase made the coverage area much larger, and made it easier for tiny receivers with simple antennas to receive the signal. This resulted in the introduction of many new low-cost radio controlled clocks that "set themselves" to agree with NIST time. </p> <div class="mw-heading mw-heading3"><h3 id="Service_improvement_plans">Service improvement plans</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=2" title="Edit section: Service improvement plans"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>WWVB's Colorado location makes the signal weakest on the U.S. east coast, where <a href="/wiki/Urban_density" title="Urban density">urban density</a> also produces considerable interference. In 2009, NIST raised the possibility of adding a second time code transmitter, on the east coast, to improve signal reception there and provide a certain amount of robustness to the overall system should weather or other causes render one transmitter site inoperative. Such a transmitter would use the same time code, but a different frequency.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>Use of 40 kHz would permit use of dual-frequency time code receivers <a href="/wiki/Commercial_off-the-shelf" title="Commercial off-the-shelf">already produced</a> for the Japanese <a href="/wiki/JJY" title="JJY">JJY</a> transmitters.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> With the decommissioning of the Swiss longwave time station <a href="/wiki/HBG_(time_signal)" title="HBG (time signal)">HBG</a> on 75 kHz, that frequency is potentially also available. </p><p>Plans were made to install the transmitter on the grounds of the <a href="/wiki/Redstone_Arsenal" title="Redstone Arsenal">Redstone Arsenal</a> in <a href="/wiki/Huntsville,_Alabama" title="Huntsville, Alabama">Huntsville, Alabama</a>, but the <a href="/wiki/Marshall_Space_Flight_Center" title="Marshall Space Flight Center">Marshall Space Flight Center</a> objected to having such a high power transmitter so near to their operations. Funding, which was allocated as part of the <a href="/wiki/American_Recovery_and_Reinvestment_Act_of_2009" title="American Recovery and Reinvestment Act of 2009">2009 ARRA</a> "stimulus bill", expired before the impasse could be resolved,<sup id="cite_ref-Lowe2011_14-0" class="reference"><a href="#cite_note-Lowe2011-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> and it is now unlikely to be built. </p><p>NIST explored two other ideas in 2012. One was to add a second transmission frequency at the current transmitter site. While it would not have helped signal strength, it would have reduced the incidence of interference and (frequency-dependent) multipath fading. </p><p>None of the ideas for a second transmitter were implemented. </p><p>Instead, NIST implemented the second idea, adding <a href="/wiki/Phase_modulation" title="Phase modulation">phase modulation</a> to the WWVB carrier, in 2012. This requires no additional transmitters or antennas, and phase modulation had already been used successfully by the German <a href="/wiki/DCF77#Phase_modulation" title="DCF77">DCF77</a> and French <a href="/wiki/TDF_time_signal" class="mw-redirect" title="TDF time signal">TDF time signals</a>.<sup id="cite_ref-Lowe2011_14-1" class="reference"><a href="#cite_note-Lowe2011-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> A receiver that decodes the phase modulation can have greater <a href="/wiki/Process_gain" title="Process gain">process gain</a>, allowing usable reception at a lower received <a href="/wiki/Signal-to-noise_ratio" title="Signal-to-noise ratio">signal-to-noise ratio</a> than the <a href="/wiki/Pulse-width_modulation" title="Pulse-width modulation">PWM</a>/<a href="/wiki/Amplitude-shift_keying" title="Amplitude-shift keying">ASK</a> time code. The method is more fully <a class="mw-selflink-fragment" href="#Phase_modulated_time_code">described later</a> in this article. </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=WWVB&action=edit&section=3" title="Edit section: Antennas"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div style="float: right; margin-left: 5px"> <table class="wikitable"> <tbody><tr> <th colspan="2">WWVB antenna helix house coordinates (<a href="/wiki/World_Geodetic_System#WGS84" title="World Geodetic System">WGS84</a>) </th></tr> <tr> <td>North</td> <td><span class="geo-inline"><style data-mw-deduplicate="TemplateStyles:r1156832818">.mw-parser-output .geo-default,.mw-parser-output .geo-dms,.mw-parser-output .geo-dec{display:inline}.mw-parser-output .geo-nondefault,.mw-parser-output .geo-multi-punct,.mw-parser-output .geo-inline-hidden{display:none}.mw-parser-output .longitude,.mw-parser-output .latitude{white-space:nowrap}</style><span class="plainlinks nourlexpansion"><a class="external text" href="https://geohack.toolforge.org/geohack.php?pagename=WWVB&params=40_40_50.6_N_105_3_1.7_W_region:US-CO_type:landmark&title=WWVB+-+North+antenna"><span class="geo-default"><span class="geo-dms" title="Maps, aerial photos, and other data for this location"><span class="latitude">40°40′50.6″N</span> <span class="longitude">105°3′1.7″W</span></span></span><span class="geo-multi-punct"> / </span><span class="geo-nondefault"><span class="vcard"><span class="geo-dec" title="Maps, aerial photos, and other data for this location">40.680722°N 105.050472°W</span><span style="display:none"> / <span class="geo">40.680722; -105.050472</span></span><span style="display:none"> (<span class="fn org">WWVB - North antenna</span>)</span></span></span></a></span></span> </td></tr> <tr> <td>South</td> <td><span class="geo-inline"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1156832818" /><span class="plainlinks nourlexpansion"><a class="external text" href="https://geohack.toolforge.org/geohack.php?pagename=WWVB&params=40_40_28.9_N_105_2_42.3_W_region:US-CO_type:landmark&title=WWVB+-+South+antenna"><span class="geo-default"><span class="geo-dms" title="Maps, aerial photos, and other data for this location"><span class="latitude">40°40′28.9″N</span> <span class="longitude">105°2′42.3″W</span></span></span><span class="geo-multi-punct"> / </span><span class="geo-nondefault"><span class="vcard"><span class="geo-dec" title="Maps, aerial photos, and other data for this location">40.674694°N 105.045083°W</span><span style="display:none"> / <span class="geo">40.674694; -105.045083</span></span><span style="display:none"> (<span class="fn org">WWVB - South antenna</span>)</span></span></span></a></span></span> </td></tr></tbody></table> <p><span class="geo-inline-hidden noexcerpt"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1156832818" /><span class="plainlinks nourlexpansion"><a class="external text" href="https://geohack.toolforge.org/geohack.php?pagename=WWVB&params=40_40_41_N_105_2_49_W_region:US-CO_type:landmark_dim:1430&title=WWVB+-+Transmitter+building"><span class="geo-default"><span class="geo-dms" title="Maps, aerial photos, and other data for this location"><span class="latitude">40°40′41″N</span> <span class="longitude">105°2′49″W</span></span></span><span class="geo-multi-punct"> / </span><span class="geo-nondefault"><span class="vcard"><span class="geo-dec" title="Maps, aerial photos, and other data for this location">40.67806°N 105.04694°W</span><span style="display:none"> / <span class="geo">40.67806; -105.04694</span></span><span style="display:none"> (<span class="fn org">WWVB - Transmitter building</span>)</span></span></span></a></span></span> </p> </div> <p>The WWVB signal is transmitted via a <a href="/wiki/Phased_array" title="Phased array">phased array</a> of two identical <a href="/wiki/Antenna_(radio)" title="Antenna (radio)">antenna systems</a>, spaced 2,810 feet (857 m) apart, one of which was previously used for WWVL. Each consists of four 400-foot (122 m) towers that are used to suspend a "top-loaded monopole" (<a href="/wiki/Umbrella_antenna" title="Umbrella antenna">umbrella antenna</a>), consisting of a diamond-shaped "web" of several cables in a horizontal plane (a capacitive <i>"top-hat"</i>) supported by the towers, and a <a href="/wiki/Drop_(telecommunication)" title="Drop (telecommunication)">downlead</a> (vertical cable) in the middle that connects the top-hat to a "<a href="/wiki/Helix_building" class="mw-redirect" title="Helix building">helix house</a>" on the ground. In this configuration, the downlead is the radiating element of the antenna. Each helix house contains a dual fixed-variable inductor system, which is automatically matched to the transmitter via a feedback loop to keep the antenna system at its maximum radiating efficiency. The combination of the downlead and top-hat is designed to replace a single, quarter-<a href="/wiki/Wavelength" title="Wavelength">wavelength</a> antenna, which, at 60 kHz, would have to be an impractical 4,100 feet (1,250 m) tall.<sup id="cite_ref-Oldtimer_11-1" class="reference"><a href="#cite_note-Oldtimer-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Modulation_format">Modulation format</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=4" title="Edit section: Modulation format"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>WWVB transmits data at one bit per second, taking 60 seconds to send the current time of day and date within a century. There are two independent time codes used for this purpose: An amplitude-modulated time code, which has been in use with minor changes since 1962, and a phase-modulated time code added in late 2012.<sup id="cite_ref-EnhancedWWVB_15-0" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Amplitude_modulation">Amplitude modulation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=5" title="Edit section: Amplitude modulation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The WWVB 60 kHz carrier, which has a normal ERP of 70 <a href="/wiki/Watt#Kilowatt" title="Watt">kW</a>, is reduced in power at the start of each UTC second by 17 <a href="/wiki/Decibel" title="Decibel">dB</a> (to 1.4 kW ERP). It is restored to full power some time during the second. The duration of the reduced power encodes one of three symbols: </p> <ul><li>If power is reduced for one-fifth of a second (0.2 s), this is a data bit with value zero.</li> <li>If power is reduced for one-half of a second (0.5 s), this is a data bit with value one.</li> <li>If power is reduced for four-fifths of a second (0.8 s), this is a special non-data "mark", used for framing.</li></ul> <p>Each minute, seven marks are transmitted in a regular pattern which allows the receiver to identify the beginning of the minute and thus the correct framing of the data bits. The other 53 seconds provide data bits which encode the current time, date, and related information. </p><p>Before July 12, 2005, when WWVB's maximum ERP was 50 kW, the power reduction was 10 dB, resulting in a 5 kW signal. The change to greater modulation depth was part of a series of experiments to increase coverage without increasing transmitter power.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Phase_modulation">Phase modulation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=6" title="Edit section: Phase modulation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An independent time code is transmitted by <a href="/wiki/Phase-shift_keying#Binary_phase-shift_keying_(BPSK)" title="Phase-shift keying">binary phase-shift keying</a> of the WWVB carrier. A 1 bit is encoded by inverting the phase (a 180° phase shift) of the carrier for one second. A 0 bit is transmitted with normal carrier phase. The phase shift begins 0.1 s after the corresponding UTC second, so that the transition occurs while the carrier amplitude is low.<sup id="cite_ref-EnhancedWWVB_15-1" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 2–4">: 2–4 </span></sup> </p><p>The use of phase-shift keying allows a more sophisticated (but still very simple by modern electronics standards) receiver to distinguish 0 and 1 bits far more clearly, allowing improved reception on the <a href="/wiki/East_Coast_of_the_United_States" title="East Coast of the United States">East Coast of the United States</a> where the WWVB signal level is weak, radio frequency noise is high, and the <a href="/wiki/Time_from_NPL_(MSF)" title="Time from NPL (MSF)">MSF time signal</a> from the U.K. interferes at times.<sup id="cite_ref-newimproved_17-0" class="reference"><a href="#cite_note-newimproved-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p><p>There are no markers as in the amplitude modulated time code. Minute framing is instead provided by a fixed pattern of data bits, transmitted in the last second of each minute and the first 13 seconds of the next one. Because the amplitude-modulated markers provide only 0.2 s of full-strength carrier, it is more difficult to decode their phase modulation. The phase-modulated time code therefore avoids using these bit positions within the minute for important information. </p> <div class="mw-heading mw-heading4"><h4 id="Allowance_for_carrier_phase_tracking_receivers">Allowance for carrier phase tracking receivers</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=7" title="Edit section: Allowance for carrier phase tracking receivers"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Added in late 2012, this phase modulation has no effect on popular radio-controlled clocks, which consider only the carrier's amplitude, but will cripple (rare) receivers that track the carrier phase.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>To allow users of phase tracking receivers time to adjust, the phase-modulated time code was initially omitted twice daily for 30 minutes, beginning at noon and midnight Mountain Standard time (07:00 and 19:00 UTC). This provided enough opportunity for a receiver to lock on to the WWVB carrier phase. This allowance was removed as of March 21, 2013.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Station_ID">Station ID</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=8" title="Edit section: Station ID"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Prior to the addition of the phase-modulated time code, WWVB identified itself by advancing the phase of its carrier wave by 45° at ten minutes past the hour, and returning to normal (a −45° shift) five minutes later. This phase step was equivalent to "cutting and pasting" <style data-mw-deduplicate="TemplateStyles:r1154941027">.mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style><span class="frac"><span class="num">1</span>⁄<span class="den">8</span></span> of a 60 kHz carrier cycle, or approximately 2.08 <a href="/wiki/Microsecond" title="Microsecond">μs</a>. </p><p>This station ID method was common for narrowband high power transmitters in the VLF and LF bands where other intervening factors prevent normal methods of transmitting call letters. </p><p>When the phase modulation time code was added in late 2012, this station identification was eliminated; the time code format itself serves as station identification.<sup id="cite_ref-EnhancedWWVB_15-2" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 2">: 2 </span></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Amplitude-modulated_time_code">Amplitude-modulated time code</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=9" title="Edit section: Amplitude-modulated time code"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Each minute, WWVB broadcasts the current time in a binary-coded decimal format. While this is based on the <a href="/wiki/IRIG_timecode" title="IRIG timecode">IRIG timecode</a>, the bit encoding and the order of the transmitted bits differs from any current or past IRIG time distribution standard. </p> <ul><li>Markers are sent during seconds 0, 9, 19, 29, 39, 49, and 59 of each minute. Thus, the start of the second of two consecutive markers indicates the top of the minute, and serves as the on-time marker for the next frame of time code. Markers are important to allow receivers to properly frame the time code.</li> <li>A marker is also sent during <a href="/wiki/Leap_second" title="Leap second">leap seconds</a>. In this exceptional event, three consecutive markers will be transmitted: one in second 59, one in second 60, and one in second 0. The start of the third marker indicates the start of the minute.</li> <li>There are 11 unused bits, transmitted as binary 0.</li> <li>The remaining 42 bits, zeros and ones, carry the binary time code and other information.</li></ul> <p>The on-time marker, the exact moment which the time code identifies, is the leading (negative-going) edge of the frame reference marker. Thus the time code is always transmitted in the minute immediately after the moment it represents, and matches the hours and minutes of the time of day a clock should be displaying at that moment in UTC (before any time zone or daylight saving offsets are applied). </p><p> In the following diagram, the cyan (0 dBr) blocks indicate the full strength carrier, and the dark blue (−17 dBr) blocks indicate the reduced strength carrier. The widest dark blue blocks — the longest intervals (0.8 s) of reduced carrier strength — are the markers, occurring in seconds 0, 9, 19, 29, 39, 49, and 59. Of the remaining dark blue blocks, the narrowest represent reduced carrier strength of 0.2 seconds duration, hence data bits of value zero. Those of intermediate width (for example, in seconds :02 and :03) represent reduced carrier strength of 0.5 seconds duration, hence data bits of value one.</p><div style="clear:both;" class=""></div> <figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:WWVB_time_code_format.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f0/WWVB_time_code_format.svg/960px-WWVB_time_code_format.svg.png" decoding="async" width="750" height="131" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f0/WWVB_time_code_format.svg/1125px-WWVB_time_code_format.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f0/WWVB_time_code_format.svg/1500px-WWVB_time_code_format.svg.png 2x" data-file-width="976" data-file-height="170" /></a><figcaption></figcaption></figure> <p>The example above encodes the following: </p> <ul><li>day 66 (March 6) of 2008</li> <li>for the minute beginning at 07:30:00 UTC</li> <li><a href="/wiki/DUT1" title="DUT1">DUT1</a> is −0.3 seconds (therefore, <a href="/wiki/Universal_Time#Versions" title="Universal Time">UT1</a> is 07:29:59.7)</li> <li>DST is not in effect today, nor is it coming into effect</li> <li>there is no leap second pending, but the current year <i>is</i> a leap year</li></ul> <p>The table below shows this in more detail, with the "Ex" column being the bits from the example above: </p> <table class="wikitable" style="text-align:center;"> <caption>WWVB time code structure </caption> <tbody><tr> <th>Bit</th> <th>Weight</th> <th>Meaning</th> <th>Ex </th> <td rowspan="21"> </td> <th>Bit</th> <th>Weight</th> <th>Meaning</th> <th>Ex </th> <td rowspan="21"> </td> <th>Bit</th> <th>Weight</th> <th>Meaning</th> <th>Ex </th></tr> <tr> <td bgcolor="lightpink">:00</td> <td bgcolor="lightpink">FRM</td> <td bgcolor="lightpink">Frame reference marker</td> <td bgcolor="lightpink">M </td> <td bgcolor="lightgrey">:20</td> <td bgcolor="lightgrey">0</td> <td rowspan="2" bgcolor="lightgrey"><i>Unused, always 0.</i></td> <td bgcolor="lightgrey">0 </td> <td>:40</td> <td>0.8</td> <td rowspan="4">DUT1 value (0–0.9 s).<br />DUT1 = <a href="/wiki/Universal_Time#Versions" title="Universal Time">UT1</a>−UTC.<br /><i>Example:0.3</i></td> <td>0 </td></tr> <tr> <td>:01</td> <td>40</td> <td rowspan="8">Minutes (00–59)<br /><i>Example: 30</i></td> <td>0 </td> <td bgcolor="lightgrey">:21</td> <td bgcolor="lightgrey">0</td> <td bgcolor="lightgrey">0 </td> <td>:41</td> <td>0.4</td> <td>0 </td></tr> <tr> <td>:02</td> <td>20</td> <td>1 </td> <td>:22</td> <td>200</td> <td rowspan="12"><a href="/wiki/Ordinal_date" title="Ordinal date">Day of year</a><br />1=January 1<br />365=December 31<br />(366 if a leap year)<br /><i>Example: 66 (March 6)</i></td> <td>0 </td> <td>:42</td> <td>0.2</td> <td>1 </td></tr> <tr> <td>:03</td> <td>10</td> <td>1 </td> <td>:23</td> <td>100</td> <td>0 </td> <td>:43</td> <td>0.1</td> <td>1 </td></tr> <tr bgcolor="lightgrey"> <td>:04</td> <td>0</td> <td>0 </td> <td>:24</td> <td>0</td> <td>0 </td> <td>:44</td> <td>0</td> <td><i>Unused, always 0.</i></td> <td>0 </td></tr> <tr> <td>:05</td> <td>8</td> <td>0 </td> <td>:25</td> <td>80</td> <td>0 </td> <td>:45</td> <td>80</td> <td rowspan="9">Year (00–99)<br /><i>Example: 08</i></td> <td>0 </td></tr> <tr> <td>:06</td> <td>4</td> <td>0 </td> <td>:26</td> <td>40</td> <td>1 </td> <td>:46</td> <td>40</td> <td>0 </td></tr> <tr> <td>:07</td> <td>2</td> <td>0 </td> <td>:27</td> <td>20</td> <td>1 </td> <td>:47</td> <td>20</td> <td>0 </td></tr> <tr> <td>:08</td> <td>1</td> <td>0 </td> <td>:28</td> <td>10</td> <td>0 </td> <td>:48</td> <td>10</td> <td>0 </td></tr> <tr bgcolor="lightpink"> <td>:09</td> <td>P1</td> <td>Marker</td> <td>M </td> <td>:29</td> <td>P3</td> <td>M </td> <td>:49</td> <td>P5</td> <td>M </td></tr> <tr> <td bgcolor="lightgrey">:10</td> <td bgcolor="lightgrey">0</td> <td rowspan="2" bgcolor="lightgrey"><i>Unused, always 0.</i></td> <td bgcolor="lightgrey">0 </td> <td>:30</td> <td>8</td> <td>0 </td> <td>:50</td> <td>8</td> <td>1 </td></tr> <tr> <td bgcolor="lightgrey">:11</td> <td bgcolor="lightgrey">0</td> <td bgcolor="lightgrey">0 </td> <td>:31</td> <td>4</td> <td>1 </td> <td>:51</td> <td>4</td> <td>0 </td></tr> <tr> <td>:12</td> <td>20</td> <td rowspan="7">Hours (00–23)<br /><i>Example: 07</i></td> <td>0 </td> <td>:32</td> <td>2</td> <td>1 </td> <td>:52</td> <td>2</td> <td>0 </td></tr> <tr> <td>:13</td> <td>10</td> <td>0 </td> <td>:33</td> <td>1</td> <td>0 </td> <td>:53</td> <td>1</td> <td>0 </td></tr> <tr bgcolor="lightgrey"> <td>:14</td> <td>0</td> <td>0 </td> <td>:34</td> <td>0</td> <td rowspan="2"><i>Unused, always 0.</i></td> <td>0 </td> <td>:54</td> <td>0</td> <td><i>Unused, always 0.</i><sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup></td> <td>0 </td></tr> <tr> <td>:15</td> <td>8</td> <td>0 </td> <td bgcolor="lightgrey">:35</td> <td bgcolor="lightgrey">0</td> <td bgcolor="lightgrey">0 </td> <td>:55</td> <td>LYI</td> <td>Leap year indicator</td> <td>1 </td></tr> <tr> <td>:16</td> <td>4</td> <td>1 </td> <td>:36</td> <td>+</td> <td rowspan="3"><a href="/wiki/DUT1" title="DUT1">DUT1</a> sign.<br />If +, bits 36 and 38 are set.<br />If −, bit 37 is set.<br /><i>Example: −</i></td> <td>0 </td> <td>:56</td> <td>LSW</td> <td>Leap second at end of month</td> <td>0 </td></tr> <tr> <td>:17</td> <td>2</td> <td>1 </td> <td>:37</td> <td>−</td> <td>1 </td> <td>:57</td> <td>2</td> <td rowspan="2"><i>DST status value <a href="/wiki/Gray_code" title="Gray code">(binary)</a>:</i><br /><div align="left">00 = DST not in effect.<br />10 = DST begins today.<br />11 = DST in effect.<br />01 = DST ends today.</div></td> <td>0 </td></tr> <tr> <td>:18</td> <td>1</td> <td>1 </td> <td>:38</td> <td>+</td> <td>0 </td> <td>:58</td> <td>1</td> <td>0 </td></tr> <tr bgcolor="lightpink"> <td>:19</td> <td>P2</td> <td>Marker</td> <td>M </td> <td>:39</td> <td>P4</td> <td>Marker</td> <td>M </td> <td>:59</td> <td>P0</td> <td>Marker</td> <td>M </td></tr></tbody></table> <div class="mw-heading mw-heading3"><h3 id="Announcement_bits">Announcement bits</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=10" title="Edit section: Announcement bits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Several bits of the WWVB time code give warning of upcoming events. </p><p>Bit 55, when set, indicates that the current year is a <a href="/wiki/Leap_year" title="Leap year">leap year</a> and includes February 29. This lets a receiver translate the day number into a month and day according to the <a href="/wiki/Gregorian_calendar" title="Gregorian calendar">Gregorian calendar</a> leap-year rules even though the time code does not include the century. </p><p>When a leap second is scheduled for the end of a month, bit 56 is set near the beginning of the month, and reset immediately after the leap second insertion. </p><p>The DST status bits indicate <a href="/wiki/Time_in_the_United_States#Daylight_saving_time_(DST)" title="Time in the United States">United States daylight saving time rules</a>. The bits are updated daily during the minute starting at 00:00 UTC. The first DST bit, transmitted at 57 seconds past the minute, changes at the beginning of the UTC day that DST comes into effect or ends. The other DST bit, at second 58, changes 24 hours later (after the DST change). Therefore, if the DST bits differ, DST is changing at 02:00 local time during the current UTC day. Before the next 02:00 local time after that, the bits will be the same. </p><p>Each change in the DST bits will first be received in the mainland United States between 16:00 PST and 20:00 EDT, depending on the local time zone and on whether DST is about to begin or end. A receiver in the Eastern time zone (UTC−5) must, therefore, correctly receive the "DST is changing" indication within a seven-hour period before DST begins, and six hours before DST ends, if it is to change the local time display at the correct time. Therefore, receivers in the Central, Mountain, and Pacific time zones have one, two, and three more hours of advance notice, respectively. </p><p>It is up to the receiving clock to apply the change at the next 02:00 local time if it notices the bits differ. If the receiving clock happens not to receive an update between 00:00 UTC and 02:00 local time the day of the change, it should apply the DST change on the next update after that. </p><p>An equivalent definition of the DST status bits is that bit 57 is set if DST will be in effect at 24:00 Z, the end of the current UTC day. Bit 58 is set if DST was in effect at 00:00 Z, the beginning of the current UTC day. </p> <div class="mw-heading mw-heading2"><h2 id="Phase_modulated_time_code">Phase modulated time code</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=11" title="Edit section: Phase modulated time code"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The phase-modulated time code has been completely updated and is not related to the amplitude-modulated time code. The only connection is that it is also transmitted in 60 second frames, and the amplitude-modulated markers (when only 20% of the second is transmitted at full strength) are not used for essential time code information. </p> <div class="mw-heading mw-heading3"><h3 id="One-minute_time_frames">One-minute time frames</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=12" title="Edit section: One-minute time frames"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The time is transmitted as a 26-bit "minute of century" from 0 to 52595999 (or 52594559 in centuries with only 24 leap years).<sup id="cite_ref-EnhancedWWVB_15-3" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> Like the amplitude-modulated code, the time is transmitted in the minute after the instant it identifies; clocks must increment it for display. </p><p>An additional 5 error-correcting bits produce a 31-bit <a href="/wiki/Hamming_code" title="Hamming code">Hamming code</a> that can correct single-bit errors or detect double-bit errors (<a href="/wiki/Hamming_code#Hamming_codes_with_additional_parity_(SECDED)" title="Hamming code">but not both</a>). </p><p>Another field encodes DST and leap-second announcement bits similar to standard WWVB, and a new 6-bit field provides greatly advanced warning of scheduled DST changes. </p><p>The 60 bits transmitted each minute are divided as follows: </p> <ul><li>14 fixed sync bits (0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0)</li> <li>32 bits of time, comprising: <ul><li>26-bit binary minute of century (0–52595999 for 36525 days per century)</li> <li>5 ECC bits, making a Hamming (31,26) code</li> <li>1-bit copy of the least significant bit of the minute</li></ul></li> <li>5 bits of DST status and leap pending, comprising: <ul><li>2 bits of DST status, as in the amplitude modulated code</li> <li>2 bits (3 possibilities) of leap second warning</li> <li>1 odd parity bit (with one exception, see below)</li></ul></li> <li>6-bit DST rules code, comprising: <ul><li>2 bits indicating time of next change (1/2/3 o'clock, or never)</li> <li>3 bits indicating date of change (which Sunday)</li> <li>1 odd parity bit (with one exception, see below)</li></ul></li> <li>1 bit of "NIST notice"</li> <li>2 reserved bits</li></ul> <p>A receiver that already knows the time to within a few seconds can synchronize to the fixed synchronization pattern, even when it is unable to distinguish individual time code bits. </p><p>The full time code (with the amplitude-modulated code for reference) is transmitted as follows: </p> <table class="wikitable" style="text-align:center;"> <caption>WWVB phase-modulated time code<sup id="cite_ref-EnhancedWWVB_15-4" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page: 5">: 5 </span></sup> </caption> <tbody><tr> <th>Bit</th> <th>Amp.</th> <th>Ex</th> <th>Phase</th> <th>Meaning</th> <th>Ex </th> <td rowspan="21"> </td> <th>Bit</th> <th>Amp.</th> <th>Ex</th> <th>Phase</th> <th>Meaning</th> <th>Ex </th> <td rowspan="21"> </td> <th>Bit</th> <th>Amp.</th> <th>Ex</th> <th>Phase</th> <th>Meaning</th> <th>Ex </th></tr> <tr> <td bgcolor="lightpink">:00</td> <td bgcolor="lightpink">FRM</td> <td bgcolor="lightpink">M</td> <td bgcolor="#ccffff">sync[12]</td> <td rowspan="13" bgcolor="#ccffff">Fixed<br />sync<br />pattern</td> <td bgcolor="#ccffff">0 </td> <td>:20</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">time[24]</td> <td rowspan="19" bgcolor="#ccffcc">Binary<br />minute of<br />century<br />0 – 52,<br />595,999</td> <td bgcolor="#ccffcc">0 </td> <td>:40</td> <td rowspan="4">DUT1</td> <td>0</td> <td bgcolor="#ccffcc">time[6]</td> <td rowspan="7" bgcolor="#ccffcc"></td> <td bgcolor="#ccffcc">0 </td></tr> <tr> <td>:01</td> <td rowspan="3">Minute<br />tens</td> <td>0</td> <td bgcolor="#ccffff">sync[11]</td> <td bgcolor="#ccffff">0 </td> <td>:21</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">time[23]</td> <td bgcolor="#ccffcc">0 </td> <td>:41</td> <td>1</td> <td bgcolor="#ccffcc">time[5]</td> <td bgcolor="#ccffcc">0 </td></tr> <tr> <td>:02</td> <td>1</td> <td bgcolor="#ccffff">sync[10]</td> <td bgcolor="#ccffff">1 </td> <td>:22</td> <td rowspan="2">Day<br />100s</td> <td>0</td> <td bgcolor="#ccffcc">time[22]</td> <td bgcolor="#ccffcc">1 </td> <td>:42</td> <td>0</td> <td bgcolor="#ccffcc">time[4]</td> <td bgcolor="#ccffcc">1 </td></tr> <tr> <td>:03</td> <td>1</td> <td bgcolor="#ccffff">sync[9]</td> <td bgcolor="#ccffff">1 </td> <td>:23</td> <td>1</td> <td bgcolor="#ccffcc">time[21]</td> <td bgcolor="#ccffcc">1 </td> <td>:43</td> <td>0</td> <td bgcolor="#ccffcc">time[3]</td> <td bgcolor="#ccffcc">1 </td></tr> <tr> <td>:04</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffff">sync[8]</td> <td bgcolor="#ccffff">1 </td> <td>:24</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">time[20]</td> <td bgcolor="#ccffcc">0 </td> <td>:44</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">time[2]</td> <td bgcolor="#ccffcc">0 </td></tr> <tr> <td>:05</td> <td rowspan="4">Minute<br />ones</td> <td>0</td> <td bgcolor="#ccffff">sync[7]</td> <td bgcolor="#ccffff">0 </td> <td>:25</td> <td rowspan="4">Day<br />tens</td> <td>1</td> <td bgcolor="#ccffcc">time[19]</td> <td bgcolor="#ccffcc">0 </td> <td>:45</td> <td rowspan="4">Year<br />tens</td> <td>0</td> <td bgcolor="#ccffcc">time[1]</td> <td bgcolor="#ccffcc">1 </td></tr> <tr> <td>:06</td> <td>0</td> <td bgcolor="#ccffff">sync[6]</td> <td bgcolor="#ccffff">1 </td> <td>:26</td> <td>0</td> <td bgcolor="#ccffcc">time[18]</td> <td bgcolor="#ccffcc">1 </td> <td>:46</td> <td>0</td> <td bgcolor="#ccffcc">time[0]</td> <td bgcolor="#ccffcc">0 </td></tr> <tr> <td>:07</td> <td>0</td> <td bgcolor="#ccffff">sync[5]</td> <td bgcolor="#ccffff">1 </td> <td>:27</td> <td>0</td> <td bgcolor="#ccffcc">time[17]</td> <td bgcolor="#ccffcc">0 </td> <td>:47</td> <td>0</td> <td bgcolor="#ffccff">dst_ls[4]</td> <td rowspan="6" bgcolor="#ffccff">DST/<br />Leap<br />second<br />warning</td> <td bgcolor="#ffccff">0 </td></tr> <tr> <td>:08</td> <td>0</td> <td bgcolor="#ccffff">sync[4]</td> <td bgcolor="#ccffff">0 </td> <td>:28</td> <td>0</td> <td bgcolor="#ccffcc">time[16]</td> <td bgcolor="#ccffcc">0 </td> <td>:48</td> <td>1</td> <td bgcolor="#ffccff">dst_ls[3]</td> <td bgcolor="#ffccff">0 </td></tr> <tr bgcolor="lightpink"> <td>:09</td> <td>M</td> <td>P1</td> <td bgcolor="#ccffff">sync[3]</td> <td bgcolor="#ccffff">1 </td> <td>:29</td> <td>M</td> <td>P3</td> <td bgcolor="lightgrey">R</td> <td bgcolor="lightgrey">0 </td> <td>:49</td> <td>M</td> <td>P5</td> <td bgcolor="#ff88ff">notice</td> <td bgcolor="#ff88ff">1 </td></tr> <tr> <td>:10</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffff">sync[2]</td> <td bgcolor="#ccffff">0 </td> <td>:30</td> <td rowspan="4">Day<br />ones</td> <td>0</td> <td bgcolor="#ccffcc">time[15]</td> <td bgcolor="#ccffcc">0 </td> <td>:50</td> <td rowspan="4">Year<br />ones</td> <td>0</td> <td bgcolor="#ffccff">dst_ls[2]</td> <td bgcolor="#ffccff">0 </td></tr> <tr> <td>:11</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffff">sync[1]</td> <td bgcolor="#ccffff">0 </td> <td>:31</td> <td>1</td> <td bgcolor="#ccffcc">time[14]</td> <td bgcolor="#ccffcc">1 </td> <td>:51</td> <td>0</td> <td bgcolor="#ffccff">dst_ls[1]</td> <td bgcolor="#ffccff">1 </td></tr> <tr> <td>:12</td> <td rowspan="2">Hour<br />tens</td> <td>0</td> <td bgcolor="#ccffff">sync[0]</td> <td bgcolor="#ccffff">0 </td> <td>:32</td> <td>1</td> <td bgcolor="#ccffcc">time[13]</td> <td bgcolor="#ccffcc">1 </td> <td>:52</td> <td>1</td> <td bgcolor="#ffccff">dst_ls[0]</td> <td bgcolor="#ffccff">1 </td></tr> <tr> <td>:13</td> <td>1</td> <td bgcolor="#ccffcc">timepar[4]</td> <td rowspan="5" bgcolor="#ccffcc">Time<br />parity<br />(ECC)</td> <td bgcolor="#ccffcc">1 </td> <td>:33</td> <td>0</td> <td bgcolor="#ccffcc">time[12]</td> <td bgcolor="#ccffcc">0 </td> <td>:53</td> <td>0</td> <td bgcolor="#ffffcc">dst_next[5]</td> <td rowspan="6" bgcolor="#ffffcc">Next DST<br />schedule</td> <td bgcolor="#ffffcc">0 </td></tr> <tr> <td>:14</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">timepar[3]</td> <td bgcolor="#ccffcc">0 </td> <td>:34</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">time[11]</td> <td bgcolor="#ccffcc">0 </td> <td>:54</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ffffcc">dst_next[4]</td> <td bgcolor="#ffffcc">1 </td></tr> <tr> <td>:15</td> <td rowspan="4">Hour<br />ones</td> <td>0</td> <td bgcolor="#ccffcc">timepar[2]</td> <td bgcolor="#ccffcc">0 </td> <td>:35</td> <td bgcolor="lightgrey">—</td> <td bgcolor="lightgrey">0</td> <td bgcolor="#ccffcc">time[10]</td> <td bgcolor="#ccffcc">0 </td> <td>:55</td> <td>LYI</td> <td>1</td> <td bgcolor="#ffffcc">dst_next[3]</td> <td bgcolor="#ffffcc">1 </td></tr> <tr> <td>:16</td> <td>1</td> <td bgcolor="#ccffcc">timepar[1]</td> <td bgcolor="#ccffcc">1 </td> <td>:36</td> <td rowspan="3">DUT1<br />sign</td> <td>1</td> <td bgcolor="#ccffcc">time[9]</td> <td bgcolor="#ccffcc">1 </td> <td>:56</td> <td>LSW</td> <td>0</td> <td bgcolor="#ffffcc">dst_next[2]</td> <td bgcolor="#ffffcc">0 </td></tr> <tr> <td>:17</td> <td>1</td> <td bgcolor="#ccffcc">timepar[0]</td> <td bgcolor="#ccffcc">0 </td> <td>:37</td> <td>0</td> <td bgcolor="#ccffcc">time[8]</td> <td bgcolor="#ccffcc">1 </td> <td>:57</td> <td rowspan="2">DST</td> <td>1</td> <td bgcolor="#ffffcc">dst_next[1]</td> <td bgcolor="#ffffcc">1 </td></tr> <tr> <td>:18</td> <td>1</td> <td bgcolor="#ccffcc">time[25]</td> <td bgcolor="#ccffcc"></td> <td bgcolor="#ccffcc">0 </td> <td>:38</td> <td>1</td> <td bgcolor="#ccffcc">time[7]</td> <td bgcolor="#ccffcc">0 </td> <td>:58</td> <td>1</td> <td bgcolor="#ffffcc">dst_next[0]</td> <td bgcolor="#ffffcc">1 </td></tr> <tr bgcolor="lightpink"> <td>:19</td> <td>M</td> <td>P2</td> <td bgcolor="#ccffcc">time[0]</td> <td bgcolor="#ccffcc">(duplicate)</td> <td bgcolor="#ccffcc">0 </td> <td>:39</td> <td>M</td> <td>P4</td> <td bgcolor="lightgrey">R</td> <td bgcolor="lightgrey">reserved</td> <td bgcolor="lightgrey">1 </td> <td>:59</td> <td>M</td> <td>P0</td> <td bgcolor="#ccffff">sync[13]</td> <td bgcolor="#ccffff"></td> <td bgcolor="#ccffff">0 </td></tr></tbody></table> <p>Bits within fields are numbered from bit 0 as the least-significant bit; each field is transmitted most significant bit first. </p><p>The example shows the time code transmitted on July 4, 2012 between 17:30 and 17:31 UTC.<sup id="cite_ref-EnhancedWWVB_15-5" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page: 12–13">: 12–13 </span></sup> The BCD amplitude code shows a time of 17:30, on day 186 of the year. </p><p>The binary time code shows minute <span class="nowrap">0x064631A = 6578970</span> of the century. Dividing by 1440 minutes per day, this is minute 1050 <span class="nowrap">(= 17×60 + 30)</span> of day 4568 of the century. There are <span class="nowrap">365×12 + 3 = 4383 days</span> in the 12 years before 2012, so this is day 185 of the year. This day number begins at 0 on January 1, rather than 1 like the BCD time code, so it encodes the same date. </p> <div class="mw-heading mw-heading3"><h3 id="Announcement_bits_2">Announcement bits</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=13" title="Edit section: Announcement bits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The phase-modulated code contains additional announcement bits useful for converting the broadcast UTC to civil time. </p><p>In addition to the DST and leap second warning bits found in the amplitude-modulated code, an additional DST schedule field provides several months advance warning of <a href="/wiki/Daylight_saving_time_in_the_United_States" title="Daylight saving time in the United States">daylight saving time rules</a>. </p><p>A final bit, the "notice" bit, indicates that there is an announcement of interest to WWVB users posted at <a rel="nofollow" class="external text" href="https://www.nist.gov/pml/div688/grp40/wwvb.cfm">nist.gov/pml/div688/grp40/wwvb.cfm</a>. </p><p>Two reserved bits are not currently defined, but <i>not</i> guaranteed to be zero; note that one of them is transmitted as 1 in the example above. </p><p>The DUT1 information (+0.4 s) and leap year indicator bits (2012 is a leap year) in the amplitude modulated code are not included in the phase modulated code; the use of DUT1 for <a href="/wiki/Celestial_navigation" title="Celestial navigation">celestial navigation</a> has been obsoleted by <a href="/wiki/Satellite_navigation" title="Satellite navigation">satellite navigation</a>. </p> <div class="mw-heading mw-heading4"><h4 id="DST_and_leap_second_warning">DST and leap second warning</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=14" title="Edit section: DST and leap second warning"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The phase-modulated time code contains daylight saving time announcement and leap second warning information equivalent to the amplitude-modulated code, but they are combined into one 5-bit field for error detection purposes. </p><p>There are two DST announcement bits that let a receiver apply U.S. daylight saving time rules: </p> <ul><li>dst_on[0] is set if DST was in effect at the beginning of the current UTC day (00:00 UTC).</li> <li>dst_on[1] is set if DST will be in effect at the end of the current UTC day (24:00 UTC).</li></ul> <p>The two bits differ on days when daylight saving time is changing (at 02:00 local time). </p><p>There are also three leap second warning possibilities (0, +1, or −1 seconds), making twelve possible values that need to be encoded. Eleven of these are encoded as 5-bit codes with <a href="/wiki/Parity_bit" title="Parity bit">odd parity</a>, providing single-bit error detection (a minimum <a href="/wiki/Hamming_distance" title="Hamming distance">Hamming distance</a> of 2 between any two valid codes). </p><p>Five of the 16 possible odd-parity values (all those differing in one bit from 00011) are not used, and the even-parity value 00011 is used to encode the most common condition: DST in effect, no leap second pending. This provides single-bit error <i>correction</i> (a minimum Hamming distance of 3) whenever this code is transmitted. </p> <table class="wikitable"> <caption>WWVB Phase-modulated warning bits </caption> <tbody><tr> <th colspan="3">DST warning</th> <th colspan="3">Leap warning </th></tr> <tr> <th>Meaning</th> <th>dst_on[0]</th> <th>dst_on[1]</th> <th>0</th> <th>+1</th> <th>−1 </th></tr> <tr> <td>Not in effect</td> <td>0</td> <td>0</td> <td>01000</td> <td>11001</td> <td>00100 </td></tr> <tr> <td>Begins today</td> <td>0</td> <td>1</td> <td>10110</td> <td>11010</td> <td>10000 </td></tr> <tr> <td>In effect</td> <td>1</td> <td>1</td> <td bgcolor="#ffccff">00011</td> <td>11111</td> <td>01101 </td></tr> <tr> <td>Ends today</td> <td>1</td> <td>0</td> <td>10101</td> <td>11100</td> <td>01110 </td></tr></tbody></table> <p>The above example illustrates this common case: DST is in effect, and no leap second is pending (the last leap second was 4 days ago). </p><p>During a leap second, bit 59 (a marker bit with a phase-modulated code of 0) is transmitted again. </p> <div class="mw-heading mw-heading4"><h4 id="DST_schedule">DST schedule</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=15" title="Edit section: DST schedule"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>To extend the few hours' warning provided by dst_on[1], another 6-bit field encodes the schedule for the next DST change. The encoding is somewhat intricate, but effectively provides 5 bits of information. Three bits supply the date of the change, either 0 to 7 Sundays after the first Sunday in March (when dst_on[1] = 0), or 4 Sundays before to 3 Sundays after the first Sunday in November (when dst_on[1] = 1). </p><p>Two more bits encode the time of the change: 1:00, 2:00, or 3:00 AM local time. The fourth combination of these two bits encodes (using the date-of-change bits) several special cases: DST at some other time, DST always off, DST always on, and five reserved codes. </p><p>As with the other warning field, most of the assigned 6-bit codes have odd parity, providing a Hamming distance of 2 from each other. However, 6 of the 32 odd-parity codes are not used (all those differing in one bit from 011011), and the even-parity code 011011 is used to encode the most common DST rule (2nd Sunday in March, or 1st Sunday in November) with a Hamming distance of 3. </p><p>The five additional reserved codes are assigned to other even-parity code words a Hamming distance of 1 from unlikely DST rule codes. </p><p>The example code of 011011 indicates a DST change at 02:00 on the first Sunday in November. </p> <div class="mw-heading mw-heading3"><h3 id="Message_frames">Message frames</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=16" title="Edit section: Message frames"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A small percentage of the time code frames (typically less than 10%)<sup id="cite_ref-EnhancedWWVB_15-6" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 5">: 5 </span></sup> may be replaced by one-minute message frames, containing other information, such as emergency broadcasts. </p><p>The details of such frames have not been finalized, but they will begin with an alternate synchronization word (1101000111010, and a 0 during second 59), and include 42 bits of non-time data in the non-marker bits of the time code. Message frames still contain time[0] during second 19 and the notice bit during second 49, so a receiver which knows the time to within ±1 minute can synchronize to them. </p><p>Messages are expected to span multiple message frames. </p> <div class="mw-heading mw-heading3"><h3 id="Six-minute_time_frames">Six-minute time frames</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=WWVB&action=edit&section=17" title="Edit section: Six-minute time frames"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>For six minutes each half hour, from 10–16 and 40–46 minutes past each hour, one-minute frames are replaced by a special extended time frame. Rather than transmitting 35 bits of information in one minute, this transmits 7 bits (time of day and DST status only) over 6 minutes, giving 30 times as much energy per transmitted bit, a 14.8 dB improvement in the <a href="/wiki/Link_budget" title="Link budget">link budget</a> compared to the standard one-minute time code.<sup id="cite_ref-EnhancedWWVB_15-7" class="reference"><a href="#cite_note-EnhancedWWVB-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page: 13–17">: 13–17 </span></sup> </p><p>The 360-bit code word consists of three parts: </p> <ul><li>A 127-bit sequence (generated by a 7-bit <a href="/wiki/Linear-feedback_shift_register" title="Linear-feedback shift register">linear-feedback shift register</a>), rotated left by a variable amount to encode a value from 0 to 123.</li> <li>A 106-bit fixed bit sequence.</li> <li>The 127-bit reverse of the initial sequence. Because it is reversed, it is effectively rotated in the opposite direction.</li></ul> <p>The only information transmitted is the time within the day (one of 48 half hours), plus the current U.S. daylight saving time status, making <span class="nowrap">2×48 = 96 possible</span> time codes. </p><p>An additional <span class="nowrap">2×14 = 28 time</span> codes are transmitted between 04:10 and 10:46 UTC on days when daylight saving time is changing, providing several hours' warning of an imminent DST change. </p> <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=WWVB&action=edit&section=18" title="Edit section: Propagation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Since WWVB's <a href="/wiki/Low_frequency" title="Low frequency">low frequency</a> signal tends to propagate better <a href="/wiki/Ground_wave" title="Ground wave">along the ground</a>, the signal path from transmitter to the receiver is shorter and less turbulent than WWV's <a href="/wiki/Shortwave_radio" title="Shortwave radio">shortwave</a> signal, which is strongest when it <a href="/wiki/Skywave" title="Skywave">bounces</a> between the <a href="/wiki/Ionosphere" title="Ionosphere">ionosphere</a> and the ground. This results in the WWVB signal having greater accuracy than the WWV signal as received at the same site. Also, since longwave signals tend to propagate much farther at night, the WWVB signal can reach a larger coverage area during that time period, which is why many radio-controlled clocks are designed to automatically synchronize with the WWVB time code during local nighttime hours. </p><p> The radiation pattern of WWVB antennas is designed to present a field <a href="/wiki/Signal_strength_in_telecommunications" title="Signal strength in telecommunications">strength</a> of at least 100 μV/m over most of the continental United States and Southern Canada during some portion of the day. Although this value is well above the <a href="/wiki/Johnson%E2%80%93Nyquist_noise" title="Johnson–Nyquist noise">thermal noise</a> <a href="/wiki/Noise_floor" title="Noise floor">floor</a>, man-made noise and local interference from a wide range of electronic equipment can easily mask the signal. Positioning receiving antennas away from electronic equipment helps to reduce the effects of local interference.</p><div style="clear:both;" class=""></div> <p><br /> </p> <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=WWVB&action=edit&section=19" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Radio_clock" title="Radio clock">Radio clock</a></li> <li><a href="/wiki/Watch#Electronic" title="Watch">Watch (electronic movements)</a></li> <li><a href="/wiki/Time_from_NPL_(MSF)" title="Time from NPL (MSF)">Time from NPL (MSF)</a>, similar time service in the United Kingdom</li> <li><a href="/wiki/DCF77" title="DCF77">DCF77</a>, similar time service in Germany</li></ul> <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=WWVB&action=edit&section=20" title="Edit section: References"><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-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-homepage-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-homepage_1-0">^</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://www.nist.gov/pml/div688/grp40/wwvb.cfm">"NIST Radio Station WWVB"</a>. NIST. March 2010. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20240521120735/https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb">Archived</a> from the original on 21 May 2024<span class="reference-accessdate">. Retrieved <span class="nowrap">1 June</span> 2024</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NIST+Radio+Station+WWVB&rft.pub=NIST&rft.date=2010-03&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fdiv688%2Fgrp40%2Fwwvb.cfm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</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://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwvb/help-wwvb-radio-controlled-clocks#where">"Help with WWVB Radio Controlled Clocks - Where They Work"</a>. <i>National Institute of Standards and Technology</i>. February 11, 2010. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200317133233/https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwvb/help-wwvb-radio-controlled-clocks#where">Archived</a> from the original on March 17, 2020<span class="reference-accessdate">. Retrieved <span class="nowrap">March 23,</span> 2020</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=National+Institute+of+Standards+and+Technology&rft.atitle=Help+with+WWVB+Radio+Controlled+Clocks+-+Where+They+Work&rft.date=2010-02-11&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Ftime-and-frequency-division%2Fradio-stations%2Fwwvb%2Fhelp-wwvb-radio-controlled-clocks%23where&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/div688/grp40/radioclocks.cfm">"WWVB Radio-Controlled Clocks"</a>. National Institute of Standards and Technology. 5 March 2012. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120521164121/http://www.nist.gov/pml/div688/grp40/radioclocks.cfm">Archived</a> from the original on 21 May 2012<span class="reference-accessdate">. Retrieved <span class="nowrap">21 May</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WWVB+Radio-Controlled+Clocks&rft.pub=National+Institute+of+Standards+and+Technology&rft.date=2012-03-05&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fdiv688%2Fgrp40%2Fradioclocks.cfm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></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 id="CITEREFLombardi2010" class="citation journal cs1">Lombardi, Michael A. (March 2010). <a rel="nofollow" class="external text" href="http://tf.nist.gov/general/pdf/2429.pdf">"How Accurate is a Radio Controlled Clock?"</a> <span class="cs1-format">(PDF)</span>. <i>Horological Journal</i>. <b>152</b> (3). The British Horological Institute, Limited: <span class="nowrap">108–</span>111. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210107194406/https://tf.nist.gov/general/pdf/2429.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 7 January 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">3 August</span> 2016</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Horological+Journal&rft.atitle=How+Accurate+is+a+Radio+Controlled+Clock%3F&rft.volume=152&rft.issue=3&rft.pages=%3Cspan+class%3D%22nowrap%22%3E108-%3C%2Fspan%3E111&rft.date=2010-03&rft.aulast=Lombardi&rft.aufirst=Michael+A.&rft_id=http%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F2429.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" 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 web cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/newsletter/radio.cfm">"All Time, All the Time: Improving NIST Radio"</a>. NIST. October 3, 2011. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160812024838/http://nist.gov/pml/newsletter/radio.cfm">Archived</a> from the original on August 12, 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">July 13,</span> 2017</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=All+Time%2C+All+the+Time%3A+Improving+NIST+Radio&rft.pub=NIST&rft.date=2011-10-03&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fnewsletter%2Fradio.cfm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" 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 web cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/director/fy-2019-presidential-budget-request-summary/fundamental-measurement-quantum-science-and">"NIST Budget Request"</a>. NIST. 9 February 2018. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180820121617/https://www.nist.gov/director/fy-2019-presidential-budget-request-summary/fundamental-measurement-quantum-science-and">Archived</a> from the original on 20 August 2018<span class="reference-accessdate">. Retrieved <span class="nowrap">21 June</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NIST+Budget+Request&rft.pub=NIST&rft.date=2018-02-09&rft_id=https%3A%2F%2Fwww.nist.gov%2Fdirector%2Ffy-2019-presidential-budget-request-summary%2Ffundamental-measurement-quantum-science-and&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</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://swling.com/blog/2019/02/fy-2019-nist-budget-looks-good-for-time-stations/">"FY 2019 NIST budget looks good for time stations"</a>. The SWLing Post. 15 February 2019. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20190225161906/https://swling.com/blog/2019/02/fy-2019-nist-budget-looks-good-for-time-stations/">Archived</a> from the original on 25 February 2019<span class="reference-accessdate">. Retrieved <span class="nowrap">24 February</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=FY+2019+NIST+budget+looks+good+for+time+stations&rft.pub=The+SWLing+Post&rft.date=2019-02-15&rft_id=https%3A%2F%2Fswling.com%2Fblog%2F2019%2F02%2Ffy-2019-nist-budget-looks-good-for-time-stations%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb">"Radio Station WWVB"</a>. <i>NIST</i>. July 4, 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NIST&rft.atitle=Radio+Station+WWVB&rft.date=2024-07-04&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Ftime-and-frequency-division%2Ftime-distribution%2Fradio-station-wwvb&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</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://tf.nist.gov/general/pdf/1746.pdf">"NBS Miscellaneous Publication 236 (1967 edition): NBS Standard Frequency and Time Services"</a> <span class="cs1-format">(PDF)</span>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170517011215/http://tf.nist.gov/general/pdf/1746.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on May 17, 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">April 11,</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NBS+Miscellaneous+Publication+236+%281967+edition%29%3A+NBS+Standard+Frequency+and+Time+Services&rft_id=https%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F1746.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" 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 web cs1"><a rel="nofollow" class="external text" href="https://nvlpubs.nist.gov/nistpubs/jres/119/jres.119.004.pdf">"<span class="cs1-kern-left"></span>"WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio", retrieved December 2, 2019"</a> <span class="cs1-format">(PDF)</span>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180605154350/https://nvlpubs.nist.gov/nistpubs/jres/119/jres.119.004.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on June 5, 2018<span class="reference-accessdate">. Retrieved <span class="nowrap">December 2,</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=%22WWVB%3A+A+Half+Century+of+Delivering+Accurate+Frequency+and+Time+by+Radio%22%2C+retrieved+December+2%2C+2019.&rft_id=https%3A%2F%2Fnvlpubs.nist.gov%2Fnistpubs%2Fjres%2F119%2Fjres.119.004.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-Oldtimer-11"><span class="mw-cite-backlink">^ <a href="#cite_ref-Oldtimer_11-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Oldtimer_11-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFDeutchHansonNelsonSnider1999" class="citation conference cs1">Deutch, Matthew; Hanson, Wayne; Nelson, Glenn; Snider, Charles; Sutton, Douglas; Yates, William; Hansen, Peder; Hopkins, Bill (December 1999). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090816105657/http://tf.nist.gov/timefreq/general/pdf/1406.pdf"><i>WWVB Improvements: New Power from an Old Timer</i></a> <span class="cs1-format">(PDF)</span>. 31st Annual <abbr title="Precise Time and Time Interval">PTTI</abbr> Meeting. Dana Point, California: National Institute of Standards and Technology. Archived from <a rel="nofollow" class="external text" href="http://tf.nist.gov/timefreq/general/pdf/1406.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 16 August 2009<span class="reference-accessdate">. Retrieved <span class="nowrap">1 May</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=WWVB+Improvements%3A+New+Power+from+an+Old+Timer&rft.place=Dana+Point%2C+California&rft.pub=National+Institute+of+Standards+and+Technology&rft.date=1999-12&rft.aulast=Deutch&rft.aufirst=Matthew&rft.au=Hanson%2C+Wayne&rft.au=Nelson%2C+Glenn&rft.au=Snider%2C+Charles&rft.au=Sutton%2C+Douglas&rft.au=Yates%2C+William&rft.au=Hansen%2C+Peder&rft.au=Hopkins%2C+Bill&rft_id=http%3A%2F%2Ftf.nist.gov%2Ftimefreq%2Fgeneral%2Fpdf%2F1406.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" 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 journal cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100323010350/http://www.radioworld.com/article/9286">"NIST Eyes East Coast Version of WWVB"</a>. <i>Radio World</i>. 18 January 2008. Archived from <a rel="nofollow" class="external text" href="http://www.radioworld.com/article/9286">the original</a> on 23 March 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">30 March</span> 2009</span>. <q>The National Institute of Standards and Technology is considering setting up a U.S. East Coast low-frequency radio station broadcasting NIST time in binary code format to complement the present NIST 60 kHz, WWVB broadcast. "The proposed new East Coast broadcast will operate with the same time code format as the present WWVB signal, however at a different carrier frequency, potentially at 40 kHz," John Lowe, the WWVB station manager, told RW.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Radio+World&rft.atitle=NIST+Eyes+East+Coast+Version+of+WWVB&rft.date=2008-01-18&rft_id=http%3A%2F%2Fwww.radioworld.com%2Farticle%2F9286&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></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">For example, the dual-frequency time code receiver IC <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100226002401/http://www.mas-oy.com/data/MAS_docu.htm">"MAS6181"</a>. Helsinki, Finland: Micro Analog Systems Oy. Archived from <a rel="nofollow" class="external text" href="http://www.mas-oy.com/data/MAS_docu.htm">the original</a> on 26 February 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=MAS6181&rft.place=Helsinki%2C+Finland&rft.pub=Micro+Analog+Systems+Oy&rft_id=http%3A%2F%2Fwww.mas-oy.com%2Fdata%2FMAS_docu.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-Lowe2011-14"><span class="mw-cite-backlink">^ <a href="#cite_ref-Lowe2011_14-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Lowe2011_14-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFJohn_Lowe2011" class="citation magazine cs1">John Lowe (23 March 2011). <a rel="nofollow" class="external text" href="http://tf.boulder.nist.gov/general/pdf/2504.pdf">"We Help Move Time Through the Air: Managers of WWVB Explore Options to Improve the Service Further"</a> <span class="cs1-format">(PDF)</span>. <i>Radio World</i>. Vol. 35, no. 8. pp. 70–69 (published backwards)<span class="reference-accessdate">. Retrieved <span class="nowrap">7 April</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Radio+World&rft.atitle=We+Help+Move+Time+Through+the+Air%3A+Managers+of+WWVB+Explore+Options+to+Improve+the+Service+Further&rft.volume=35&rft.issue=8&rft.pages=70-69+%28published+backwards%29&rft.date=2011-03-23&rft.au=John+Lowe&rft_id=http%3A%2F%2Ftf.boulder.nist.gov%2Fgeneral%2Fpdf%2F2504.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-EnhancedWWVB-15"><span class="mw-cite-backlink">^ <a href="#cite_ref-EnhancedWWVB_15-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-4"><sup><i><b>e</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-5"><sup><i><b>f</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-6"><sup><i><b>g</b></i></sup></a> <a href="#cite_ref-EnhancedWWVB_15-7"><sup><i><b>h</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLowe2013" class="citation web cs1">Lowe, John (6 November 2013). <a rel="nofollow" class="external text" href="https://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf">"Enhanced WWVB Broadcast Format"</a> <span class="cs1-format">(PDF)</span>. Time and Frequency Services, National Institute of Standards and Technology. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160304193155/http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 4 March 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">1 March</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Enhanced+WWVB+Broadcast+Format&rft.pub=Time+and+Frequency+Services%2C+National+Institute+of+Standards+and+Technology&rft.date=2013-11-06&rft.aulast=Lowe&rft.aufirst=John&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fdiv688%2Fgrp40%2Fupload%2FNIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLoweAllen2006" class="citation conference cs1">Lowe, John P.; Allen, Ken C. (June 2006). <a rel="nofollow" class="external text" href="http://tf.nist.gov/general/pdf/2139.pdf"><i>Increasing the modulation depth of the WWVB time code to improve the performance of radio-controlled clocks</i></a> <span class="cs1-format">(PDF)</span>. International Frequency Control Symposium and Exposition. pp. <span class="nowrap">615–</span>621. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20211010002816/https://tf.nist.gov/general/pdf/2139.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 10 October 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">14 February</span> 2010</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=Increasing+the+modulation+depth+of+the+WWVB+time+code+to+improve+the+performance+of+radio-controlled+clocks&rft.pages=%3Cspan+class%3D%22nowrap%22%3E615-%3C%2Fspan%3E621&rft.date=2006-06&rft.aulast=Lowe&rft.aufirst=John+P.&rft.au=Allen%2C+Ken+C.&rft_id=http%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F2139.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-newimproved-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-newimproved_17-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLoweDeutschNelsonSutton2011" class="citation conference cs1">Lowe, John; Deutsch, Matt; Nelson, Glenn; Sutton, Douglas; Yates, William; Hansen, Peder; Eliezer, Oren; Jung, Tom; Morrison, Stephen; Liang, Yingsi; Rajan, Dinesh; Balasubramanian, Sidharth; Ramasami, Arun; Khalil, Waleed (November 2011). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20131126085433/http://www.jks.com/wwvb.pdf"><i>New Improved System for WWVB Broadcast</i></a> <span class="cs1-format">(PDF)</span>. 43rd Annual PTTI Meeting. Archived from <a rel="nofollow" class="external text" href="http://jks.com/wwvb.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 26 November 2013<span class="reference-accessdate">. Retrieved <span class="nowrap">28 March</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=New+Improved+System+for+WWVB+Broadcast&rft.date=2011-11&rft.aulast=Lowe&rft.aufirst=John&rft.au=Deutsch%2C+Matt&rft.au=Nelson%2C+Glenn&rft.au=Sutton%2C+Douglas&rft.au=Yates%2C+William&rft.au=Hansen%2C+Peder&rft.au=Eliezer%2C+Oren&rft.au=Jung%2C+Tom&rft.au=Morrison%2C+Stephen&rft.au=Liang%2C+Yingsi&rft.au=Rajan%2C+Dinesh&rft.au=Balasubramanian%2C+Sidharth&rft.au=Ramasami%2C+Arun&rft.au=Khalil%2C+Waleed&rft_id=http%3A%2F%2Fjks.com%2Fwwvb.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</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://www.orolia.com/documents/changes-wwvb-radio-signal-affects-precision-frequency-and-timing-reference">"Pending Changes in the WWVB Radio Signal Affects Precision Frequency and Timing Reference"</a>. Orolia. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210305225915/https://www.orolia.com/documents/changes-wwvb-radio-signal-affects-precision-frequency-and-timing-reference">Archived</a> from the original on March 5, 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">January 6,</span> 2021</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Pending+Changes+in+the+WWVB+Radio+Signal+Affects+Precision+Frequency+and+Timing+Reference&rft.pub=Orolia&rft_id=https%3A%2F%2Fwww.orolia.com%2Fdocuments%2Fchanges-wwvb-radio-signal-affects-precision-frequency-and-timing-reference&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFRuss_Miller_(WA3FRP)2013" class="citation mailinglist cs1">Russ Miller (WA3FRP) (22 March 2013). <a rel="nofollow" class="external text" href="http://www.febo.com/pipermail/time-nuts/2013-March/075133.html">"WWVB fully converts to new format"</a>. <i>time-nuts</i> (Mailing list). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20211010002852/https://www.febo.com/pipermail/time-nuts/2013-March/075133.html">Archived</a> from the original on 10 October 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">8 April</span> 2013</span>. <q>As of yesterday 21 March 2013, WWVB has stopped the twice daily 30 minute segments of this format.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WWVB+fully+converts+to+new+format&rft.date=2013-03-22&rft.au=Russ+Miller+%28WA3FRP%29&rft_id=http%3A%2F%2Fwww.febo.com%2Fpipermail%2Ftime-nuts%2F2013-March%2F075133.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_mailing_list" title="Template:Cite mailing list">cite mailing list</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-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">From June 21 – July 10, 2007 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://tf.nist.gov/stations/wwvb2007outages.htm">"WWVB experimented with using bit 54 to give more advance DST warning"</a>. NIST. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20211010002854/https://tf.nist.gov/stations/wwvb2007outages.htm">Archived</a> from the original on October 10, 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">March 31,</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WWVB+experimented+with+using+bit+54+to+give+more+advance+DST+warning&rft.pub=NIST&rft_id=http%3A%2F%2Ftf.nist.gov%2Fstations%2Fwwvb2007outages.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span>. Because of adverse effects on some radio-controlled clocks, it was decided not to implement the new DST system.</span> </li> </ol></div> <p><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLombardiNelson2014" class="citation journal cs1">Lombardi, Michael A.; Nelson, Glenn K. (12 March 2014). <a rel="nofollow" class="external text" href="http://nvlpubs.nist.gov/nistpubs/jres/119/jres.119.004.pdf">"WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio"</a> <span class="cs1-format">(PDF)</span>. <i>Journal of Research of the National Institute of Standards and Technology</i>. <b>119</b>. National Institute of Standards and Technology: <span class="nowrap">25–</span>54. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.6028%2Fjres.119.004">10.6028/jres.119.004</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2165-7254">2165-7254</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4487279">4487279</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26601026">26601026</a><span class="reference-accessdate">. Retrieved <span class="nowrap">24 August</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Research+of+the+National+Institute+of+Standards+and+Technology&rft.atitle=WWVB%3A+A+Half+Century+of+Delivering+Accurate+Frequency+and+Time+by+Radio&rft.volume=119&rft.pages=%3Cspan+class%3D%22nowrap%22%3E25-%3C%2Fspan%3E54&rft.date=2014-03-12&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4487279%23id-name%3DPMC&rft.issn=2165-7254&rft_id=info%3Apmid%2F26601026&rft_id=info%3Adoi%2F10.6028%2Fjres.119.004&rft.aulast=Lombardi&rft.aufirst=Michael+A.&rft.au=Nelson%2C+Glenn+K.&rft_id=http%3A%2F%2Fnvlpubs.nist.gov%2Fnistpubs%2Fjres%2F119%2Fjres.119.004.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> </p> <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=WWVB&action=edit&section=21" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><div class="side-box metadata side-box-right"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-text plainlist"><b>Map all coordinates using</b> <a class="external text" href="https://tools.wmflabs.org/osm4wiki/cgi-bin/wiki/wiki-osm.pl?project=en&article=WWVB">OpenStreetMap</a> <div class="mw-collapsible mw-collapsed" data-expandtext="show links" data-collapsetext="Hide"> <p><b>Download coordinates as:</b> </p> <div class="mw-collapsible-content"> <ul><li><a class="external text" href="https://tools.wmflabs.org/kmlexport?article=WWVB">KML</a></li> <li><a class="external text" href="https://geoexport.toolforge.org/gpx?coprimary=all&titles=WWVB">GPX (all coordinates)</a></li> <li><a class="external text" href="https://geoexport.toolforge.org/gpx?coprimary=primary&titles=WWVB">GPX (primary coordinates)</a></li> <li><a class="external text" href="https://geoexport.toolforge.org/gpx?coprimary=secondary&titles=WWVB">GPX (secondary coordinates)</a></li></ul> </div> </div></div></div> </div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwvb">"NIST Radio Station WWVB"</a>. <i>NIST</i>. March 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NIST&rft.atitle=NIST+Radio+Station+WWVB&rft.date=2010-03&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Ftime-and-frequency-division%2Fradio-stations%2Fwwvb&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – official website</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="https://tf.nist.gov/general/pdf/2422.pdf">"WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers"</a> <span class="cs1-format">(PDF)</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WWVB+Radio+Controlled+Clocks%3A+Recommended+Practices+for+Manufacturers+and+Consumers&rft_id=https%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F2422.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></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://tf.nist.gov/general/pdf/1969.pdf">"NIST Special Publication 250-67"</a> <span class="cs1-format">(PDF)</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NIST+Special+Publication+250-67&rft_id=http%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F1969.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – a detailed history and description of NIST time and frequency radio stations WWV, WWVH and WWVB.</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="https://skyscraperpage.com/cities/?buildingID=57178">"WWVB"</a>. <i><a href="/wiki/SkyscraperPage" title="SkyscraperPage">SkyscraperPage</a></i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=SkyscraperPage&rft.atitle=WWVB&rft_id=https%3A%2F%2Fskyscraperpage.com%2Fcities%2F%3FbuildingID%3D57178&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></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.buzzard.me.uk/jonathan/radioclock.html">"Simple Radio Clocks for PCs"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Simple+Radio+Clocks+for+PCs&rft_id=http%3A%2F%2Fwww.buzzard.me.uk%2Fjonathan%2Fradioclock.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – Jon Buzzard's excellent HOWTO page for making a WWVB-controlled (or MSF or DCF77) receiver for use with Network Time Protocol.</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.meinberg-usa.com/usb-radio-clocks/23-40/wwvb51usb---wwvb-radio-clock-for-the-universal-serial-bus--usb-.htm">"WWVB-controlled USB radio clock"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WWVB-controlled+USB+radio+clock&rft_id=http%3A%2F%2Fwww.meinberg-usa.com%2Fusb-radio-clocks%2F23-40%2Fwwvb51usb---wwvb-radio-clock-for-the-universal-serial-bus--usb-.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – Radio Clock for PCs with optional external antenna.</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.maxmcarter.com/rubidium/index.php">"WWVB-Based Precision Frequency Comparator"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WWVB-Based+Precision+Frequency+Comparator&rft_id=http%3A%2F%2Fwww.maxmcarter.com%2Frubidium%2Findex.php&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – Frequency standards (crystal or rubidium) characterized with WWVB receiver and stepper motor.</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.maxmcarter.com/rubidium/2012_mod/index.html">"2012 WWVB Receiver Modification"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=2012+WWVB+Receiver+Modification&rft_id=http%3A%2F%2Fwww.maxmcarter.com%2Frubidium%2F2012_mod%2Findex.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – Receiver modified to accommodate a change in WWVB's transmitted signal.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/div688/what-time.cfm">"How to get the time using a telephone, computer, or radio signal"</a>. <i>NIST</i>. February 3, 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NIST&rft.atitle=How+to+get+the+time+using+a+telephone%2C+computer%2C+or+radio+signal&rft.date=2010-02-03&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fdiv688%2Fwhat-time.cfm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWWVB" class="Z3988"></span> – Part of NIST's FAQ "What Time is It?"</li></ul> <div class="navbox-styles"><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 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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 class="mw-selflink selflink">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 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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 class="mw-selflink selflink">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:r1126788409" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /></div><div role="navigation" class="navbox" aria-labelledby="Time_signal_authorities23" 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_authorities" title="Template:Time signal authorities"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/w/index.php?title=Template_talk:Time_signal_authorities&action=edit&redlink=1" class="new" title="Template talk:Time signal authorities (page does not exist)"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Time_signal_authorities" title="Special:EditPage/Template:Time signal authorities"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Time_signal_authorities23" style="font-size:114%;margin:0 4em">Time signal authorities</div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd plainlist" 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:100%;"><tbody><tr><td class="navbox-abovebelow" style="font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/France" title="France"><img alt="France" src="//upload.wikimedia.org/wikipedia/en/thumb/c/c3/Flag_of_France.svg/20px-Flag_of_France.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/c/c3/Flag_of_France.svg/40px-Flag_of_France.svg.png 1.5x" data-file-width="900" data-file-height="600" /></a></span></span> <a href="https://fr.wikipedia.org/wiki/Agence_nationale_des_fr%C3%A9quences" class="extiw" title="fr:Agence nationale des fréquences">ANFR</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/South_Korea" title="South Korea"><img alt="South Korea" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/09/Flag_of_South_Korea.svg/40px-Flag_of_South_Korea.svg.png" decoding="async" width="21" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/09/Flag_of_South_Korea.svg/60px-Flag_of_South_Korea.svg.png 2x" data-file-width="900" data-file-height="600" /></a></span></span> <a href="/wiki/Korea_Research_Institute_of_Standards_and_Science" title="Korea Research Institute of Standards and Science">KRISS</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Finland" title="Finland"><img alt="Finland" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Flag_of_Finland.svg/40px-Flag_of_Finland.svg.png" decoding="async" width="23" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Flag_of_Finland.svg/60px-Flag_of_Finland.svg.png 2x" data-file-width="1800" data-file-height="1100" /></a></span></span> <a href="/wiki/Centre_for_Metrology_and_Accreditation" title="Centre for Metrology and Accreditation">MIKES</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Japan" title="Japan"><img alt="Japan" src="//upload.wikimedia.org/wikipedia/en/thumb/9/9e/Flag_of_Japan.svg/40px-Flag_of_Japan.svg.png" decoding="async" width="21" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/9e/Flag_of_Japan.svg/60px-Flag_of_Japan.svg.png 2x" data-file-width="900" data-file-height="600" /></a></span></span> <a href="/wiki/National_Institute_of_Information_and_Communications_Technology" title="National Institute of Information and Communications Technology">NICT</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/United_States" title="United States"><img alt="United States" src="//upload.wikimedia.org/wikipedia/en/thumb/a/a4/Flag_of_the_United_States.svg/40px-Flag_of_the_United_States.svg.png" decoding="async" width="23" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/a/a4/Flag_of_the_United_States.svg/60px-Flag_of_the_United_States.svg.png 2x" data-file-width="1235" data-file-height="650" /></a></span></span> <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">NIST</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/United_Kingdom" title="United Kingdom"><img alt="United Kingdom" src="//upload.wikimedia.org/wikipedia/en/thumb/a/ae/Flag_of_the_United_Kingdom.svg/26px-Flag_of_the_United_Kingdom.svg.png" decoding="async" width="26" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/a/ae/Flag_of_the_United_Kingdom.svg/40px-Flag_of_the_United_Kingdom.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/a/ae/Flag_of_the_United_Kingdom.svg/52px-Flag_of_the_United_Kingdom.svg.png 2x" data-file-width="1200" data-file-height="600" /></a></span></span> <a href="/wiki/National_Physical_Laboratory_(United_Kingdom)" title="National Physical Laboratory (United Kingdom)">NPL</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Canada" title="Canada"><img alt="Canada" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Flag_of_Canada_%28Pantone%29.svg/24px-Flag_of_Canada_%28Pantone%29.svg.png" decoding="async" width="24" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Flag_of_Canada_%28Pantone%29.svg/36px-Flag_of_Canada_%28Pantone%29.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Flag_of_Canada_%28Pantone%29.svg/48px-Flag_of_Canada_%28Pantone%29.svg.png 2x" data-file-width="1200" data-file-height="600" /></a></span></span> <a href="/wiki/National_Research_Council_Canada" title="National Research Council Canada">NRC</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/China" title="China"><img alt="China" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Flag_of_the_People%27s_Republic_of_China.svg/20px-Flag_of_the_People%27s_Republic_of_China.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Flag_of_the_People%27s_Republic_of_China.svg/30px-Flag_of_the_People%27s_Republic_of_China.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Flag_of_the_People%27s_Republic_of_China.svg/39px-Flag_of_the_People%27s_Republic_of_China.svg.png 2x" data-file-width="900" data-file-height="600" /></a></span></span> <a href="/wiki/National_Time_Service_Center" title="National Time Service Center">NTSC</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Germany" title="Germany"><img alt="Germany" src="//upload.wikimedia.org/wikipedia/en/thumb/b/ba/Flag_of_Germany.svg/22px-Flag_of_Germany.svg.png" decoding="async" width="22" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/b/ba/Flag_of_Germany.svg/34px-Flag_of_Germany.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/b/ba/Flag_of_Germany.svg/44px-Flag_of_Germany.svg.png 2x" data-file-width="1000" data-file-height="600" /></a></span></span> <a href="/wiki/Physikalisch-Technische_Bundesanstalt" title="Physikalisch-Technische Bundesanstalt">PTB</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Spain" title="Spain"><img alt="Spain" src="//upload.wikimedia.org/wikipedia/en/thumb/9/9a/Flag_of_Spain.svg/20px-Flag_of_Spain.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/9a/Flag_of_Spain.svg/40px-Flag_of_Spain.svg.png 1.5x" data-file-width="750" data-file-height="500" /></a></span></span> <a href="/wiki/Real_Instituto_y_Observatorio_de_la_Armada" title="Real Instituto y Observatorio de la Armada">ROA</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Argentina" title="Argentina"><img alt="Argentina" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Flag_of_Argentina.svg/21px-Flag_of_Argentina.svg.png" decoding="async" width="21" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Flag_of_Argentina.svg/32px-Flag_of_Argentina.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Flag_of_Argentina.svg/42px-Flag_of_Argentina.svg.png 2x" data-file-width="800" data-file-height="500" /></a></span></span> <a href="/wiki/Argentine_Naval_Hydrographic_Service" title="Argentine Naval Hydrographic Service">SHN</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;"><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Russia" title="Russia"><img alt="Russia" src="//upload.wikimedia.org/wikipedia/en/thumb/f/f3/Flag_of_Russia.svg/20px-Flag_of_Russia.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/f3/Flag_of_Russia.svg/40px-Flag_of_Russia.svg.png 1.5x" data-file-width="900" data-file-height="600" /></a></span></span> <a href="/wiki/All-Russian_Scientific_Research_Institute_for_Physical-Engineering_and_Radiotechnical_Metrology" title="All-Russian Scientific Research Institute for Physical-Engineering and Radiotechnical Metrology">VNIIFTRI</a></td><td class="navbox-abovebelow" style="border-left:2px solid #fdfdfd;font-weight:bold;font-weight: normal;">Other</td></tr><tr style="vertical-align:top"><td class="navbox-list" style="padding:0px;width:10em;"><div> <ul><li><a href="/wiki/ALS162_time_signal" title="ALS162 time signal">ALS162</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;background: #f7f7f7;width:10em;"><div> <ul><li><a href="/wiki/HLA_(radio_station)" title="HLA (radio station)">HLA</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;width:10em;"><div> <ul><li><a href="/w/index.php?title=MIKES_(radio_station)&action=edit&redlink=1" class="new" title="MIKES (radio station) (page does not exist)">MIKES</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;background: #f7f7f7;width:10em;"><div> <ul><li><a href="/wiki/JJY" title="JJY">JJY</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;width:10em;"><div> <ul><li><a class="mw-selflink selflink">WWVB</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></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;background: #f7f7f7;width:10em;"><div> <ul><li><a href="/wiki/Time_from_NPL_(MSF)" title="Time from NPL (MSF)">MSF</a></li> <li><a href="/wiki/Radio_teleswitch" title="Radio teleswitch">BBC (198 kHz)</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;width:10em;"><div> <ul><li><a href="/wiki/CHU_(radio_station)" title="CHU (radio station)">CHU</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;background: #f7f7f7;width:10em;"><div> <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/BPM_(time_service)" title="BPM (time service)">BPM</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;width:10em;"><div> <ul><li><a href="/wiki/DCF77" title="DCF77">DCF77</a></li> <li><a href="https://de.wikipedia.org/wiki/Funkrundsteuertechnik" class="extiw" title="de:Funkrundsteuertechnik">DCF (EFR)</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;background: #f7f7f7;width:10em;"><div> <ul><li><a href="/wiki/ROA_Time" title="ROA Time">EBC</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;width:10em;"><div> <ul><li><a href="/w/index.php?title=LOL_(radio_station)&action=edit&redlink=1" class="new" title="LOL (radio station) (page does not exist)">LOL</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;background: #f7f7f7;width:10em;"><div> <ul><li><a href="/wiki/RBU_(radio_station)" title="RBU (radio station)">RBU</a></li> <li><a href="/wiki/Beta_(time_signal)" title="Beta (time signal)">RJH (Beta)</a></li> <li><a href="/wiki/CHAYKA" title="CHAYKA">RNS (CHAYKA)</a></li> <li><a href="/wiki/RTZ_(radio_station)" title="RTZ (radio station)">RTZ</a></li> <li><a href="/wiki/RWM" title="RWM">RWM</a></li></ul> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;width:10em;"><div> <ul><li><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Taiwan" title="Taiwan"><img alt="Taiwan" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Flag_of_the_Republic_of_China.svg/20px-Flag_of_the_Republic_of_China.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Flag_of_the_Republic_of_China.svg/40px-Flag_of_the_Republic_of_China.svg.png 1.5x" data-file-width="900" data-file-height="600" /></a></span></span> <a href="/wiki/BSF_(time_service)" title="BSF (time service)">BSF</a></li> <li><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Ecuador" title="Ecuador"><img alt="Ecuador" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Flag_of_Ecuador.svg/20px-Flag_of_Ecuador.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Flag_of_Ecuador.svg/40px-Flag_of_Ecuador.svg.png 1.5x" data-file-width="1440" data-file-height="960" /></a></span></span> <a href="/wiki/HD2IOA" title="HD2IOA">HD2IOA</a></li> <li><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Italy" title="Italy"><img alt="Italy" src="//upload.wikimedia.org/wikipedia/en/thumb/0/03/Flag_of_Italy.svg/20px-Flag_of_Italy.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/0/03/Flag_of_Italy.svg/40px-Flag_of_Italy.svg.png 1.5x" data-file-width="1500" data-file-height="1000" /></a></span></span> <a href="/wiki/JN53DV" title="JN53DV">JN53DV</a></li> <li><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Brazil" title="Brazil"><img alt="Brazil" src="//upload.wikimedia.org/wikipedia/en/thumb/0/05/Flag_of_Brazil.svg/20px-Flag_of_Brazil.svg.png" decoding="async" width="19" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/0/05/Flag_of_Brazil.svg/40px-Flag_of_Brazil.svg.png 1.5x" data-file-width="1000" data-file-height="700" /></a></span></span> <a href="/w/index.php?title=PPE_(radio_station)&action=edit&redlink=1" class="new" title="PPE (radio station) (page does not exist)">PPE</a></li> <li><span class="flagicon"><span class="mw-default-size mw-image-border" typeof="mw:File"><a href="/wiki/Venezuela" title="Venezuela"><img alt="Venezuela" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Flag_of_Venezuela.svg/20px-Flag_of_Venezuela.svg.png" decoding="async" width="20" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Flag_of_Venezuela.svg/40px-Flag_of_Venezuela.svg.png 1.5x" data-file-width="900" data-file-height="600" /></a></span></span> 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