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class="vector-toc-text"> <span class="vector-toc-numb">1.2.1</span> <span>Alternator transmitter</span> </div> </a> <ul id="toc-Alternator_transmitter-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Arc_transmitters" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Arc_transmitters"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2.2</span> <span>Arc transmitters</span> </div> </a> <ul id="toc-Arc_transmitters-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Vacuum_tube_transmitters" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Vacuum_tube_transmitters"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2.3</span> <span>Vacuum tube transmitters</span> </div> </a> <ul id="toc-Vacuum_tube_transmitters-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Receivers" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Receivers"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>Receivers</span> </div> </a> <ul id="toc-Receivers-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Early_experimental_broadcasts" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Early_experimental_broadcasts"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.4</span> <span>Early experimental broadcasts</span> </div> </a> <ul id="toc-Early_experimental_broadcasts-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Organized_broadcasting" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Organized_broadcasting"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.5</span> <span>Organized broadcasting</span> </div> </a> <ul id="toc-Organized_broadcasting-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Radio_networks" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Radio_networks"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.6</span> <span>Radio networks</span> </div> </a> <ul id="toc-Radio_networks-sublist" class="vector-toc-list"> <li id="toc-United_States" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#United_States"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.6.1</span> <span>United States</span> </div> </a> <ul id="toc-United_States-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_Kingdom" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#United_Kingdom"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.6.2</span> <span>United Kingdom</span> </div> </a> <ul id="toc-United_Kingdom-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-"Golden_Age_of_Radio"" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#"Golden_Age_of_Radio""> <div class="vector-toc-text"> <span class="vector-toc-numb">1.7</span> <span>"Golden Age of Radio"</span> </div> </a> <ul id="toc-"Golden_Age_of_Radio"-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Decline_in_popularity" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Decline_in_popularity"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.8</span> <span>Decline in popularity</span> </div> </a> <ul id="toc-Decline_in_popularity-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-AM_band_revitalization_efforts_in_the_United_States" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#AM_band_revitalization_efforts_in_the_United_States"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>AM band revitalization efforts in the United States</span> </div> </a> <button aria-controls="toc-AM_band_revitalization_efforts_in_the_United_States-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 AM band revitalization efforts in the United States subsection</span> </button> <ul id="toc-AM_band_revitalization_efforts_in_the_United_States-sublist" class="vector-toc-list"> <li id="toc-Fairness_Doctrine_repeal" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Fairness_Doctrine_repeal"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Fairness Doctrine repeal</span> </div> </a> <ul id="toc-Fairness_Doctrine_repeal-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-AM_stereo_and_AMAX_standards" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#AM_stereo_and_AMAX_standards"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>AM stereo and AMAX standards</span> </div> </a> <ul id="toc-AM_stereo_and_AMAX_standards-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Expanded_band" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Expanded_band"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Expanded band</span> </div> </a> <ul id="toc-Expanded_band-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-HD_radio" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#HD_radio"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>HD radio</span> </div> </a> <ul id="toc-HD_radio-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-FM_translator_stations" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#FM_translator_stations"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>FM translator stations</span> </div> </a> <ul id="toc-FM_translator_stations-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Additional_activities" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Additional_activities"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.6</span> <span>Additional activities</span> </div> </a> <ul id="toc-Additional_activities-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Electric_vehicles" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Electric_vehicles"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.7</span> <span>Electric vehicles</span> </div> </a> <ul id="toc-Electric_vehicles-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Technical_information" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Technical_information"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Technical information</span> </div> </a> <button aria-controls="toc-Technical_information-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 Technical information subsection</span> </button> <ul id="toc-Technical_information-sublist" class="vector-toc-list"> <li id="toc-Broadcast_band_frequencies" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Broadcast_band_frequencies"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Broadcast band frequencies</span> </div> </a> <ul id="toc-Broadcast_band_frequencies-sublist" class="vector-toc-list"> <li id="toc-Longwave_broadcasting" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Longwave_broadcasting"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1.1</span> <span>Longwave broadcasting</span> </div> </a> <ul id="toc-Longwave_broadcasting-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Medium-wave_broadcasting" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Medium-wave_broadcasting"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1.2</span> <span>Medium-wave broadcasting</span> </div> </a> <ul id="toc-Medium-wave_broadcasting-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Shortwave_broadcasting" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Shortwave_broadcasting"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1.3</span> <span>Shortwave broadcasting</span> </div> </a> <ul id="toc-Shortwave_broadcasting-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-VHF_AM_broadcasting" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#VHF_AM_broadcasting"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1.4</span> <span>VHF AM broadcasting</span> </div> </a> <ul id="toc-VHF_AM_broadcasting-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Other_distribution_methods" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_distribution_methods"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Other distribution methods</span> </div> </a> <ul id="toc-Other_distribution_methods-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Microbroadcasting" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Microbroadcasting"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Microbroadcasting</span> </div> </a> <ul id="toc-Microbroadcasting-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</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"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>References</span> </div> </a> <ul id="toc-References-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" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">AM broadcasting</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. Available in 21 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-21" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">21 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A8%D8%AB_%D8%A5%D8%B0%D8%A7%D8%B9%D9%8A_%D8%A8%D8%AA%D8%B6%D9%85%D9%8A%D9%86_%D8%A7%D9%84%D8%B3%D8%B9%D8%A9" title="بث إذاعي بتضمين السعة – Arabic" lang="ar" hreflang="ar" data-title="بث إذاعي بتضمين السعة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/R%C3%A0dio_AM" title="Ràdio AM – Catalan" lang="ca" hreflang="ca" data-title="Ràdio AM" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/AM-radio" title="AM-radio – Danish" lang="da" hreflang="da" data-title="AM-radio" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/AM-raadio" title="AM-raadio – Estonian" lang="et" hreflang="et" data-title="AM-raadio" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%95%CE%BA%CF%80%CE%BF%CE%BC%CF%80%CE%AE_%CE%91%CE%9C" title="Εκπομπή ΑΜ – Greek" lang="el" hreflang="el" data-title="Εκπομπή ΑΜ" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Radio_AM" title="Radio AM – Spanish" lang="es" hreflang="es" data-title="Radio AM" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/AM_irrati" title="AM irrati – Basque" lang="eu" hreflang="eu" data-title="AM irrati" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%BE%D8%AE%D8%B4_%D8%A7%DB%8C%E2%80%8C%D8%A7%D9%85" title="پخش ای‌ام – Persian" lang="fa" hreflang="fa" data-title="پخش ای‌ام" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Radio_AM" title="Radio AM – French" lang="fr" hreflang="fr" data-title="Radio AM" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%A4%91%ED%8C%8C%EB%B0%A9%EC%86%A1" title="중파방송 – Korean" lang="ko" hreflang="ko" data-title="중파방송" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%8F_%E0%A4%8F%E0%A4%AE_%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%B8%E0%A4%BE%E0%A4%B0%E0%A4%A3" title="ए एम प्रसारण – Hindi" lang="hi" hreflang="hi" data-title="ए एम प्रसारण" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A9%D7%99%D7%93%D7%95%D7%A8%D7%99_AM" title="שידורי AM – Hebrew" lang="he" hreflang="he" data-title="שידורי AM" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-pam mw-list-item"><a href="https://pam.wikipedia.org/wiki/Radiung_AM" title="Radiung AM – Pampanga" lang="pam" hreflang="pam" data-title="Radiung AM" data-language-autonym="Kapampangan" data-language-local-name="Pampanga" class="interlanguage-link-target"><span>Kapampangan</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E4%B8%AD%E6%B3%A2%E6%94%BE%E9%80%81" title="中波放送 – Japanese" lang="ja" hreflang="ja" data-title="中波放送" 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-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/R%C3%A1dio_AM" title="Rádio AM – Portuguese" lang="pt" hreflang="pt" data-title="Rádio AM" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%81%E0%B8%B2%E0%B8%A3%E0%B9%81%E0%B8%9E%E0%B8%A3%E0%B9%88%E0%B8%AA%E0%B8%B1%E0%B8%8D%E0%B8%8D%E0%B8%B2%E0%B8%93%E0%B9%80%E0%B8%AD%E0%B9%80%E0%B8%AD%E0%B9%87%E0%B8%A1" title="การแพร่สัญญาณเอเอ็ม – Thai" lang="th" hreflang="th" data-title="การแพร่สัญญาณเอเอ็ม" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/AM_radyo" title="AM radyo – Turkish" lang="tr" hreflang="tr" data-title="AM radyo" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/AM-%D1%80%D0%B0%D0%B4%D1%96%D0%BE" title="AM-радіо – Ukrainian" lang="uk" hreflang="uk" data-title="AM-радіо" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Ph%C3%A1t_thanh_AM" title="Phát thanh AM – Vietnamese" lang="vi" hreflang="vi" data-title="Phát thanh AM" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E8%B0%83%E5%B9%85%E5%B9%BF%E6%92%AD" title="调幅广播 – Wu" lang="wuu" hreflang="wuu" data-title="调幅广播" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E8%AA%BF%E5%B9%85%E5%BB%A3%E6%92%AD" title="調幅廣播 – Chinese" lang="zh" hreflang="zh" data-title="調幅廣播" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a 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data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"AM radio" redirects here. For the song by Everclear, see <a href="/wiki/AM_Radio_(song)" title="AM Radio (song)">AM Radio (song)</a>. For the American musical group, see <a href="/wiki/AM_Radio_(band)" title="AM Radio (band)">AM Radio (band)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox hproduct"><caption class="infobox-title fn">AM broadcasting</caption><tbody><tr><td colspan="2" class="infobox-subheader"><a href="/wiki/Amplitude_modulation" title="Amplitude modulation">amplitude modulation</a></td></tr><tr><th scope="row" class="infobox-label">Abbreviation</th><td class="infobox-data">AM</td></tr><tr><th scope="row" class="infobox-label">Status</th><td class="infobox-data">Active</td></tr><tr><th scope="row" class="infobox-label">Year started</th><td class="infobox-data">1901<span class="noprint">; 123 years ago</span><span style="display:none"> (<span class="bday dtstart published updated">1901</span>)</span></td></tr><tr><th scope="row" class="infobox-label">Authors</th><td class="infobox-data"><a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a></td></tr><tr><th scope="row" class="infobox-label">License</th><td class="infobox-data">Public</td></tr><tr><th scope="row" class="infobox-label">Website</th><td class="infobox-data"><span class="url"><a rel="nofollow" class="external text" href="https://www.fcc.gov/general/am-radio">www<wbr />.fcc<wbr />.gov<wbr />/general<wbr />/am-radio</a></span></td></tr></tbody></table> <p><b>AM broadcasting</b> is <a href="/wiki/Radio_broadcasting" title="Radio broadcasting">radio broadcasting</a> using <a href="/wiki/Amplitude_modulation" title="Amplitude modulation">amplitude modulation</a> (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for <a href="/wiki/Medium_wave" title="Medium wave">medium wave</a> (also known as "AM band") transmissions, but also on the <a href="/wiki/Longwave" title="Longwave">longwave</a> and <a href="/wiki/Shortwave_radio" title="Shortwave radio">shortwave radio</a> bands. </p><p>The earliest experimental AM transmissions began in the early 1900s. However, widespread AM broadcasting was not established until the 1920s, following the development of <a href="/wiki/Vacuum_tube" title="Vacuum tube">vacuum tube</a> receivers and transmitters. AM radio remained the dominant method of broadcasting for the next 30 years, a period called the "<a href="/wiki/Golden_Age_of_Radio" title="Golden Age of Radio">Golden Age of Radio</a>", until <a href="/wiki/Television_broadcasting" class="mw-redirect" title="Television broadcasting">television broadcasting</a> became widespread in the 1950s and received much of the programming previously carried by radio. Later, AM radio's audiences declined greatly due to competition from FM (<a href="/wiki/FM_broadcasting" title="FM broadcasting">frequency modulation</a>) radio, <a href="/wiki/Digital_audio_broadcasting" class="mw-redirect" title="Digital audio broadcasting">Digital Audio Broadcasting</a> (DAB), <a href="/wiki/Satellite_radio" title="Satellite radio">satellite radio</a>, <a href="/wiki/HD_Radio" title="HD Radio">HD (digital) radio</a>, <a href="/wiki/Internet_radio" title="Internet radio">Internet radio</a>, <a href="/wiki/Music_streaming_service" title="Music streaming service">music streaming services</a>, and <a href="/wiki/Podcasting" class="mw-redirect" title="Podcasting">podcasting</a>. </p><p>Compared to FM or <a href="/wiki/Digital_transmission" class="mw-redirect" title="Digital transmission">digital transmissions</a>, AM transmissions are more expensive to transmit due to the necessity of having to transmit a high power carrier wave to overcome ground losses, and the large antenna radiators required at the low broadcast frequencies, but can be sent over long distances via the ionosphere at night; however, they are much more susceptible to interference, and often have lower audio fidelity.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><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> Thus, AM broadcasters tend to specialize in spoken-word formats, such as <a href="/wiki/Talk_radio" title="Talk radio">talk radio</a>, <a href="/wiki/All-news_radio" title="All-news radio">all-news radio</a> and <a href="/wiki/Sports_radio" title="Sports radio">sports radio</a>, with music formats primarily for FM and digital stations. </p> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Amfm3-en-de.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/a/a4/Amfm3-en-de.gif" decoding="async" width="256" height="200" class="mw-file-element" data-file-width="256" data-file-height="200" /></a><figcaption>AM and FM modulated signals for radio. AM (<a href="/wiki/Amplitude_Modulation" class="mw-redirect" title="Amplitude Modulation">Amplitude Modulation</a>) and FM (<a href="/wiki/Frequency_Modulation" class="mw-redirect" title="Frequency Modulation">Frequency Modulation</a>) are types of <a href="/wiki/Modulation" title="Modulation">modulation</a> (coding). The electrical signal from program material, usually coming from a <a href="/wiki/Radio_studio" class="mw-redirect" title="Radio studio">studio</a>, is mixed with a <a href="/wiki/Carrier_wave" title="Carrier wave">carrier wave</a> of a specific frequency, then broadcast. In the case of AM, this mixing (modulation) is done by altering the <a href="/wiki/Amplitude" title="Amplitude">amplitude</a> (strength) of the carrier wave, proportional to the original signal. In contrast, in the case of FM, it is the carrier wave's <a href="/wiki/Frequency" title="Frequency">frequency</a> that is varied. A radio receiver contains a demodulator that <a href="/wiki/Demodulation" title="Demodulation">extracts</a> the original program material from the broadcast wave. </figcaption></figure> <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=AM_broadcasting&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">For broader coverage of this topic, see <a href="/wiki/History_of_radio" title="History of radio">History of radio</a> and <a href="/wiki/History_of_broadcasting" title="History of broadcasting">History of broadcasting</a>.</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/FM_broadcasting#History" title="FM broadcasting">FM broadcasting § History</a></div> <style data-mw-deduplicate="TemplateStyles:r1244412712">.mw-parser-output .templatequote{overflow:hidden;margin:1em 0;padding:0 32px}.mw-parser-output .templatequotecite{line-height:1.5em;text-align:left;margin-top:0}@media(min-width:500px){.mw-parser-output .templatequotecite{padding-left:1.6em}}</style><blockquote class="templatequote"><p>People who weren't around in the Twenties when radio exploded can't know what it meant, this milestone for mankind. Suddenly, with radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for the first time. Music came pouring in. Laughter came in. News came in. The world shrank, with radio.</p><div class="templatequotecite">— <cite><a href="/wiki/Red_Barber" title="Red Barber">Red Barber</a>, sportscaster, <sup id="cite_ref-Nahin_3-0" class="reference"><a href="#cite_note-Nahin-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup></cite></div></blockquote> <div class="mw-heading mw-heading3"><h3 id="Early_broadcasting_development">Early broadcasting development</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=2" title="Edit section: Early broadcasting development"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Mariette_Mazarin_1908_radio_broadcast.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/08/Mariette_Mazarin_1908_radio_broadcast.png/220px-Mariette_Mazarin_1908_radio_broadcast.png" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/08/Mariette_Mazarin_1908_radio_broadcast.png/330px-Mariette_Mazarin_1908_radio_broadcast.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/08/Mariette_Mazarin_1908_radio_broadcast.png/440px-Mariette_Mazarin_1908_radio_broadcast.png 2x" data-file-width="606" data-file-height="605" /></a><figcaption>One of the earliest radio broadcasts, French soprano Mariette Mazarin singing into Lee de Forest's arc transmitter in New York City on February 24, 1910</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:De_Forest_xmtr_broadcasting_presidential_election_Nov_1916.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ac/De_Forest_xmtr_broadcasting_presidential_election_Nov_1916.jpg/220px-De_Forest_xmtr_broadcasting_presidential_election_Nov_1916.jpg" decoding="async" width="220" height="308" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/ac/De_Forest_xmtr_broadcasting_presidential_election_Nov_1916.jpg/330px-De_Forest_xmtr_broadcasting_presidential_election_Nov_1916.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/a/ac/De_Forest_xmtr_broadcasting_presidential_election_Nov_1916.jpg 2x" data-file-width="425" data-file-height="595" /></a><figcaption>Lee de Forest used an early vacuum-tube transmitter to broadcast returns for the Hughes-Wilson presidential election returns on November 7, 1916, over <a href="/wiki/Radio_2XG" title="Radio 2XG">2XG</a> in New York City. Pictured is engineer Charles Logwood.</figcaption></figure> <p>The idea of broadcasting — the unrestricted transmission of signals to a widespread audience — dates back to the founding period of radio development, even though the earliest radio transmissions, originally known as "Hertzian radiation" and "wireless telegraphy", used <a href="/wiki/Spark-gap_transmitter" title="Spark-gap transmitter">spark-gap transmitters</a> that could only transmit the dots-and-dashes of <a href="/wiki/Morse_code" title="Morse code">Morse code</a>. In October 1898 a London publication, <i>The Electrician</i>, noted that "there are rare cases where, as Dr. <a href="/wiki/Oliver_Lodge" title="Oliver Lodge">[Oliver] Lodge</a> once expressed it, it might be advantageous to 'shout' the message, spreading it broadcast to receivers in all directions".<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> However, it was recognized that this would involve significant financial issues, as that same year <i>The Electrician</i> also commented "did not Prof. Lodge forget that no one wants to pay for shouting to the world on a system by which it would be impossible to prevent non-subscribers from benefiting gratuitously?"<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>On January 1, 1902, <a href="/wiki/Nathan_Stubblefield" title="Nathan Stubblefield">Nathan Stubblefield</a> gave a short-range "wireless telephone" demonstration, that included simultaneously broadcasting speech and music to seven locations throughout Murray, Kentucky. However, this was transmitted using <a href="/wiki/Electromagnetic_induction" title="Electromagnetic induction">induction</a> rather than radio signals, and although Stubblefield predicted that his system would be perfected so that "it will be possible to communicate with hundreds of homes at the same time", and "a single message can be sent from a central station to all parts of the United States", he was unable to overcome the inherent distance limitations of this technology.<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> </p><p>The earliest public radiotelegraph broadcasts were provided as government services, beginning with daily time signals inaugurated on January 1, 1905, by a number of U.S. Navy 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> In Europe, signals transmitted from a station located on the <a href="/wiki/Eiffel_Tower" title="Eiffel Tower">Eiffel Tower</a> were received throughout much of Europe. In both the United States and France this led to a small market of receiver lines geared for jewelers who needed accurate time to set their clocks, including the Ondophone in France,<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> and the De Forest RS-100 Jewelers Time Receiver in the United States<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> The ability to pick up time signal broadcasts, in addition to Morse code weather reports and news summaries, also attracted the interest of <a href="/wiki/Amateur_radio" title="Amateur radio">amateur radio</a> enthusiasts. </p> <div class="mw-heading mw-heading3"><h3 id="Early_amplitude_modulation_(AM)_transmitter_technologies"><span id="Early_amplitude_modulation_.28AM.29_transmitter_technologies"></span>Early amplitude modulation (AM) transmitter technologies</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=3" title="Edit section: Early amplitude modulation (AM) transmitter technologies"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>It was immediately recognized that, much like the telegraph had preceded the invention of the telephone, the ability to make audio radio transmissions would be a significant technical advance. Despite this knowledge, it still took two decades to perfect the technology needed to make quality audio transmissions. In addition, the telephone had rarely been used for distributing entertainment, outside of a few "<a href="/wiki/Telephone_newspaper" title="Telephone newspaper">telephone newspaper</a>" systems, most of which were established in Europe, beginning with the Paris <a href="/wiki/Th%C3%A9%C3%A2trophone" title="Théâtrophone">Théâtrophone</a>. With this in mind, most early <a href="/wiki/Radiotelephone" title="Radiotelephone">radiotelephone</a> development envisioned that the device would be more profitably developed as a "wireless telephone" for personal communication, or for providing links where regular telephone lines could not be run, rather than for the uncertain finances of broadcasting. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:15JUN1920_Melba_radio_broadcast.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7c/15JUN1920_Melba_radio_broadcast.jpg/220px-15JUN1920_Melba_radio_broadcast.jpg" decoding="async" width="220" height="283" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/7c/15JUN1920_Melba_radio_broadcast.jpg/330px-15JUN1920_Melba_radio_broadcast.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/7c/15JUN1920_Melba_radio_broadcast.jpg/440px-15JUN1920_Melba_radio_broadcast.jpg 2x" data-file-width="503" data-file-height="648" /></a><figcaption><a href="/wiki/Nellie_Melba" title="Nellie Melba">Nellie Melba</a> making a broadcast over the Marconi Chelmsford Works radio station in England on 15 June 1920</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:20111110-OC-AMW-0038_-_Flickr_-_USDAgov_(1).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/af/20111110-OC-AMW-0038_-_Flickr_-_USDAgov_%281%29.jpg/260px-20111110-OC-AMW-0038_-_Flickr_-_USDAgov_%281%29.jpg" decoding="async" width="260" height="199" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/af/20111110-OC-AMW-0038_-_Flickr_-_USDAgov_%281%29.jpg/390px-20111110-OC-AMW-0038_-_Flickr_-_USDAgov_%281%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/af/20111110-OC-AMW-0038_-_Flickr_-_USDAgov_%281%29.jpg/520px-20111110-OC-AMW-0038_-_Flickr_-_USDAgov_%281%29.jpg 2x" data-file-width="4444" data-file-height="3398" /></a><figcaption>Farmer listening to U.S. government weather and crop reports using a crystal radio in 1923. Public service government time, weather, and farm broadcasts were the first radio "broadcasts".</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Crystal_radio_advertisement.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/77/Crystal_radio_advertisement.png/290px-Crystal_radio_advertisement.png" decoding="async" width="290" height="175" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/77/Crystal_radio_advertisement.png/435px-Crystal_radio_advertisement.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/77/Crystal_radio_advertisement.png/580px-Crystal_radio_advertisement.png 2x" data-file-width="881" data-file-height="532" /></a><figcaption>A family listening to an early broadcast using a <a href="/wiki/Crystal_radio" title="Crystal radio">crystal radio</a> receiver in 1922. Crystal sets, used before the advent of vacuum tube radios in the 1920s, could not drive <a href="/wiki/Loudspeaker" title="Loudspeaker">loudspeakers</a>, so the family had to listen on earphones.</figcaption></figure> <p>The person generally credited as the primary early developer of AM technology is Canadian-born inventor <a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a>. The original spark-gap radio transmitters were impractical for transmitting audio, since they produced discontinuous pulses known as "<a href="/wiki/Damped_wave" class="mw-redirect" title="Damped wave">damped waves</a>". Fessenden realized that what was needed was a new type of radio transmitter that produced steady "undamped" (better known as "<a href="/wiki/Continuous_wave" title="Continuous wave">continuous wave</a>") signals, which could then be "modulated" to reflect the sounds being transmitted. </p><p>Fessenden's basic approach was disclosed in U.S. Patent 706,737, which he applied for on May 29, 1901, and was issued the next year. It called for the use of a high-speed <a href="/wiki/Alternator" title="Alternator">alternator</a> (referred to as "an alternating-current dynamo") that generated "pure sine waves" and produced "a continuous train of radiant waves of substantially uniform strength", or, in modern terminology, a continuous-wave (CW) transmitter.<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> Fessenden began his research on audio transmissions while doing developmental work for the United States Weather Service on Cobb Island, Maryland. Because he did not yet have a continuous-wave transmitter, initially he worked with an experimental "high-frequency spark" transmitter, taking advantage of the fact that the higher the spark rate, the closer a spark-gap transmission comes to producing continuous waves. He later reported that, in the fall of 1900, he successfully transmitted speech over a distance of about 1.6 kilometers (one mile),<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> which appears to have been the first successful audio transmission using radio signals. However, at this time the sound was far too distorted to be commercially practical.<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> For a time he continued working with more sophisticated high-frequency spark transmitters, including versions that used compressed air, which began to take on some of the characteristics of <a href="/wiki/Arc_converter" title="Arc converter">arc-transmitters</a>.<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> Fessenden attempted to sell this form of radiotelephone for point-to-point communication, but was unsuccessful.<sup id="cite_ref-FESS_14-0" class="reference"><a href="#cite_note-FESS-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Alternator_transmitter">Alternator transmitter</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=4" title="Edit section: Alternator transmitter"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Fessenden's work with high-frequency spark transmissions was only a temporary measure. His ultimate plan for creating an audio-capable transmitter was to redesign an electrical <a href="/wiki/Alternator" title="Alternator">alternator</a>, which normally produced alternating current of at most a few hundred (<a href="/wiki/Hertz" title="Hertz">Hz</a>), to increase its rotational speed and so generate currents of tens-of-thousands Hz, thus producing a steady continuous-wave transmission when connected to an aerial. The next step, adopted from standard wire-telephone practice, was to insert a simple <a href="/wiki/Carbon_microphone" title="Carbon microphone">carbon microphone</a> into the transmission line, to modulate the <a href="/wiki/Carrier_wave" title="Carrier wave">carrier wave</a> signal to produce AM audio transmissions. However, it would take many years of expensive development before even a prototype alternator-transmitter would be ready, and a few years beyond that for high-power versions to become available.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>Fessenden worked with <a href="/wiki/General_Electric" title="General Electric">General Electric</a>'s (GE) <a href="/wiki/Ernst_Alexanderson" title="Ernst Alexanderson">Ernst F. W. Alexanderson</a>, who in August 1906 delivered an improved model which operated at a transmitting frequency of approximately 50 kHz, although at low power. The alternator-transmitter achieved the goal of transmitting quality audio signals, but the lack of any way to amplify the signals meant they were somewhat weak. On December 21, 1906, Fessenden made an extensive demonstration of the new alternator-transmitter at Brant Rock, Massachusetts, showing its utility for point-to-point wireless telephony, including interconnecting his stations to the wire telephone network. As part of the demonstration, speech was transmitted 18 kilometers (11 miles) to a listening site at Plymouth, Massachusetts.<sup id="cite_ref-experiments_16-0" class="reference"><a href="#cite_note-experiments-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p><p>An <i>American Telephone Journal</i> account of the December 21 alternator-transmitter demonstration included the statement that "It is admirably adapted to the transmission of news, music, etc. as, owing to the fact that no wires are needed, simultaneous transmission to many subscribers can be effected as easily as to a few",<sup id="cite_ref-experiments_16-1" class="reference"><a href="#cite_note-experiments-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> echoing the words of a handout distributed to the demonstration witnesses, which stated "[Radio] Telephony is admirably adapted for transmitting news, stock quotations, music, race reports, etc. simultaneously over a city, on account of the fact that no wires are needed and a single apparatus can distribute to ten thousand subscribers as easily as to a few. It is proposed to erect stations for this purpose in the large cities here and abroad."<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> However, other than two holiday transmissions reportedly made shortly after these demonstrations, Fessenden does not appear to have conducted any radio broadcasts for the general public, or to have even given additional thought about the potential of a regular broadcast service, and in a 1908 article providing a comprehensive review of the potential uses for his radiotelephone invention, he made no references to broadcasting.<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>Because there was no way to amplify electrical currents at this time, modulation was usually accomplished by a carbon <a href="/wiki/Microphone" title="Microphone">microphone</a> inserted directly in the antenna wire. This meant that the full transmitter power flowed through the microphone, and even using water cooling, the power handling ability of the microphones severely limited the power of the transmissions. Ultimately only a small number of large and powerful <a href="/wiki/Alexanderson_alternator" title="Alexanderson alternator">Alexanderson alternators</a> would be developed. However, they would be almost exclusively used for long-range radiotelegraph communication, and occasionally for radiotelephone experimentation, but were never used for general broadcasting. </p> <div class="mw-heading mw-heading4"><h4 id="Arc_transmitters">Arc transmitters</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=5" title="Edit section: Arc transmitters"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Almost all of the continuous wave AM transmissions made prior to 1915 were made by versions of the <a href="/wiki/Arc_converter" title="Arc converter">arc converter</a> transmitter, which had been initially developed by <a href="/wiki/Valdemar_Poulsen" title="Valdemar Poulsen">Valdemar Poulsen</a> in 1903.<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> Arc transmitters worked by producing a pulsating electrical arc in an enclosed hydrogen atmosphere. They were much more compact than alternator transmitters, and could operate on somewhat higher transmitting frequencies. However, they suffered from some of the same deficiencies. The lack of any means to amplify electrical currents meant that, like the alternator transmitters, modulation was usually accomplished by a microphone inserted directly in the antenna wire, which again resulted in overheating issues, even with the use of water-cooled microphones. Thus, transmitter powers tended to be limited. The arc was also somewhat unstable, which reduced audio quality. Experimenters who used arc transmitters for their radiotelephone research included <a href="/wiki/Ernst_Ruhmer" title="Ernst Ruhmer">Ernst Ruhmer</a>, <a href="/wiki/Quirino_Majorana" title="Quirino Majorana">Quirino Majorana</a>, <a href="/wiki/Charles_Herrold" title="Charles Herrold">Charles "Doc" Herrold</a>, and <a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a>. </p> <div class="mw-heading mw-heading4"><h4 id="Vacuum_tube_transmitters">Vacuum tube transmitters</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=6" title="Edit section: Vacuum tube transmitters"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Advances in <a href="/wiki/Vacuum_tube" title="Vacuum tube">vacuum tube</a> technology (called "valves" in British usage), especially after around 1915, revolutionized radio technology. Vacuum tube devices could be used to amplify electrical currents, which overcame the overheating issues of needing to insert microphones directly in the transmission antenna circuit. Vacuum tube transmitters also provided high-quality AM signals, and could operate on higher transmitting frequencies than alternator and arc transmitters.<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> Non-governmental radio transmissions were prohibited in many countries during World War I, but AM radiotelephony technology advanced greatly due to wartime research, and after the war the availability of tubes sparked a great increase in the number of amateur radio stations experimenting with AM transmission of news or music. Vacuum tubes remained the central technology of radio for 40 years, until <a href="/wiki/Transistor" title="Transistor">transistors</a> began to dominate in the late 1950s, and are still used in the highest power broadcast transmitters. </p> <div class="mw-heading mw-heading3"><h3 id="Receivers">Receivers</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=7" title="Edit section: Receivers"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Vintage_Zenith_Console_Radio,_Model_12S-568,_With_the_Zenith_Robot_(or_Shutter)_Dial,_Circa_1941_(8655513293).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Vintage_Zenith_Console_Radio%2C_Model_12S-568%2C_With_the_Zenith_Robot_%28or_Shutter%29_Dial%2C_Circa_1941_%288655513293%29.jpg/220px-Vintage_Zenith_Console_Radio%2C_Model_12S-568%2C_With_the_Zenith_Robot_%28or_Shutter%29_Dial%2C_Circa_1941_%288655513293%29.jpg" decoding="async" width="220" height="318" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Vintage_Zenith_Console_Radio%2C_Model_12S-568%2C_With_the_Zenith_Robot_%28or_Shutter%29_Dial%2C_Circa_1941_%288655513293%29.jpg/330px-Vintage_Zenith_Console_Radio%2C_Model_12S-568%2C_With_the_Zenith_Robot_%28or_Shutter%29_Dial%2C_Circa_1941_%288655513293%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/23/Vintage_Zenith_Console_Radio%2C_Model_12S-568%2C_With_the_Zenith_Robot_%28or_Shutter%29_Dial%2C_Circa_1941_%288655513293%29.jpg/440px-Vintage_Zenith_Console_Radio%2C_Model_12S-568%2C_With_the_Zenith_Robot_%28or_Shutter%29_Dial%2C_Circa_1941_%288655513293%29.jpg 2x" data-file-width="1792" data-file-height="2590" /></a><figcaption>1938 Zenith Model 12-S vacuum-tube console radio, capable of picking up mediumwave and shortwave AM transmissions. "All Wave" receivers could also pick up the third AM band: longwave (LW).</figcaption></figure> <p>Unlike telegraph and telephone systems, which used completely different types of equipment, most radio receivers were equally suitable for both radiotelegraph and radiotelephone reception. In 1903 and 1904 the <a href="/wiki/Electrolytic_detector" title="Electrolytic detector">electrolytic detector</a> and <a href="/wiki/Thermionic_diode" class="mw-redirect" title="Thermionic diode">thermionic diode</a> (<a href="/wiki/Fleming_valve" title="Fleming valve">Fleming valve</a>) were invented by <a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a> and <a href="/wiki/John_Ambrose_Fleming" title="John Ambrose Fleming">John Ambrose Fleming</a>, respectively. Most important, in 1904–1906 the <a href="/wiki/Crystal_detector" title="Crystal detector">crystal detector</a>, the simplest and cheapest AM detector, was developed by <a href="/wiki/Greenleaf_Whittier_Pickard" title="Greenleaf Whittier Pickard">G. W. Pickard</a>. Homemade <a href="/wiki/Crystal_radio" title="Crystal radio">crystal radios</a> spread rapidly during the next 15 years, providing ready audiences for the first radio broadcasts. One limitation of crystals sets was the lack of amplifying the signals, so listeners had to use <a href="/wiki/Earphone" class="mw-redirect" title="Earphone">earphones</a>, and it required the development of vacuum-tube receivers before <a href="/wiki/Loudspeaker" title="Loudspeaker">loudspeakers</a> could be used. The <a href="/wiki/Loudspeaker" title="Loudspeaker">dynamic cone loudspeaker</a>, invented in 1924, greatly improved audio <a href="/wiki/Frequency_response" title="Frequency response">frequency response</a> over the previous horn speakers, allowing music to be reproduced with good fidelity.<sup id="cite_ref-McNicol13_21-0" class="reference"><a href="#cite_note-McNicol13-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> AM radio offered the highest sound quality available in a home audio device prior to the introduction of the <a href="/wiki/High-fidelity" class="mw-redirect" title="High-fidelity">high-fidelity</a>, <a href="/wiki/Long-playing" class="mw-redirect" title="Long-playing">long-playing</a> record in the late 1940s. </p><p>Listening habits changed in the 1960s due to the introduction of the revolutionary <a href="/wiki/Transistor_radio" title="Transistor radio">transistor radio</a> (Regency TR-1, the first transistor radio released December 1954), which was made possible by the invention of the <a href="/wiki/Transistor" title="Transistor">transistor</a> in 1948. (The transistor was invented at Bell labs and released in June 1948.) Their compact size — small enough to fit in a shirt pocket — and lower power requirements, compared to vacuum tubes, meant that for the first time radio receivers were readily portable. The transistor radio became the most widely used communication device in history, with billions manufactured by the 1970s. Radio became a ubiquitous "companion medium" which people could take with them anywhere they went. </p> <div class="mw-heading mw-heading3"><h3 id="Early_experimental_broadcasts">Early experimental broadcasts</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=8" title="Edit section: Early experimental broadcasts"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The demarcation between what is considered "experimental" and "organized" broadcasting is largely arbitrary. Listed below are some of the early AM radio broadcasts, which, due to their irregular schedules and limited purposes, can be classified as "experimental": </p> <ul><li><u>Christmas Eve 1906.</u> Until the early 1930s, it was generally accepted that <a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a>'s series of demonstration broadcasts begun in 1907 were the first transmissions of music and entertainment by radio. However, in 1932 an article prepared by Samuel M. Kintner, a former associate of Reginald Fessenden, asserted that Fessenden had actually conducted two earlier broadcasts.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> This claim was based solely on information included in a January 29, 1932, letter that Fessenden had sent to Kintner. (Fessenden subsequently died five months before Kintner's article appeared.) In his letter, Fessenden reported that, on the evening of December 24, 1906 (<a href="/wiki/Christmas_Eve" title="Christmas Eve">Christmas Eve</a>), he had made the first of two broadcasts of music and entertainment to a general audience, using the alternator-transmitter at Brant Rock, Massachusetts. Fessenden remembered producing a short program that included playing a phonograph record, followed by his playing the violin and singing, and closing with a Bible reading. He also stated that a second short program was broadcast on December 31 (<a href="/wiki/New_Year%27s_Eve" title="New Year's Eve">New Year's Eve</a>). The intended audience for both transmissions was primarily shipboard radio operators along the Atlantic seaboard. Fessenden claimed these two programs had been widely publicized in advance, with the Christmas Eve broadcast heard "as far down" as Norfolk, Virginia, while the New Year’s Eve broadcast had been received in the West Indies.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> However, extensive efforts to verify Fessenden's claim during both the 50th<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> and 100th<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> anniversaries of the claimed broadcasts, which included reviewing ships' radio log accounts and other contemporary sources, have so far failed to confirm that these reported holiday broadcasts actually took place.</li> <li><u>1907-1912.</u> Lee de Forest conducted multiple test broadcasts beginning in 1907, and was widely quoted promoting the potential of organized radio broadcasting. Using a series of arc transmitters, he made his first entertainment broadcast in February 1907, transmitting electronic <a href="/wiki/Telharmonium" title="Telharmonium">telharmonium</a> music from his Parker Building laboratory station in New York City.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> This was followed by tests that included, in the fall, <a href="/wiki/Eugenia_Farrar" title="Eugenia Farrar">Eugenia Farrar</a> singing "<a href="/wiki/I_Love_You_Truly" title="I Love You Truly">I Love You Truly</a>" and "<a href="/wiki/Just_Awearyin%27_for_You" title="Just Awearyin' for You">Just Awearyin' for You</a>".<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> Additional promotional events in New York included live performances by famous Metropolitan Opera stars such as Mariette Mazarin and <a href="/wiki/Enrico_Caruso" title="Enrico Caruso">Enrico Caruso</a>. He also broadcast phonograph music from the <a href="/wiki/Eiffel_Tower" title="Eiffel Tower">Eiffel Tower</a> in Paris. His company equipped the U.S. Navy's <a href="/wiki/Great_White_Fleet" title="Great White Fleet">Great White Fleet</a> with experimental arc radiotelephones for their 1908 around-the-world cruise, and the operators broadcast phonograph music as the ships entered ports like San Francisco and Honolulu.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup></li> <li><u>June 1910.</u> In a June 23, 1910, notarized letter that was published in a catalog produced by the Electro Importing Company of New York, Charles "Doc" Herrold reported that, using one of that company's spark coils to create a "high frequency spark" transmitter, he had successfully broadcast "wireless phone concerts to local amateur wireless men". Herrold lived in San Jose, California.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup></li> <li><u>1913.</u> Robert Goldschmidt began experimental radiotelephone transmissions from the <a href="/wiki/Robert_Goldschmidt#First_European_scheduled_broadcasts" title="Robert Goldschmidt">Laeken station</a>, near Brussels, Belgium, and by March 13, 1914, the tests had been heard as far away as the Eiffel Tower in Paris.<sup id="cite_ref-cahiers_30-0" class="reference"><a href="#cite_note-cahiers-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup></li> <li><u>1914–1919.</u> "University of Wisconsin electrical engineering Professor Edward Bennett sets up a personal radio transmitter on campus and in June 1915 is issued an Experimental radio station license with the call sign 9XM.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> Activities included regular Morse Code broadcasts of weather forecasts and sending game reports for a Wisconsin-Ohio State basketball game on February 17, 1917.</li> <li><u>January 15, 1920.</u> Broadcasting in the United Kingdom began with impromptu news and phonograph music over 2MT, the 15 kW experimental tube transmitter at Marconi's factory in <a href="/wiki/Chelmsford" title="Chelmsford">Chelmsford</a>, Essex, at a frequency of 120 kHz. On June 15, 1920, the <i><a href="/wiki/Daily_Mail" title="Daily Mail">Daily Mail</a></i> newspaper sponsored the first scheduled British radio concert, by the famed Australian opera diva <a href="/wiki/Nellie_Melba" title="Nellie Melba">Nellie Melba</a>.<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> This transmission was heard throughout much of Europe, including in Berlin, Paris, The Hague, Madrid, Spain, and Sweden. Chelmsford continued broadcasting concerts with noted performers. A few months later, in spite of burgeoning popularity, the government ended the broadcasts, due to complaints that the station's longwave signal was interfering with more important communication, in particular military aircraft radio.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup></li> <li><u>August 27, 1920.</u> Argentina made the first mass radio transmission as a communication medium. Medicine students of the UBA made the first radio program by transmitting Wagner's Parsifal on radio and picked up by about 100 amateurs in the city, emitting from the roof of the Teatro Colón. They kept transmitting over the nights different operas being the first in offering a radio program. There were known as the "Locos de la azotea" (the crazies of the roof).<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading3"><h3 id="Organized_broadcasting">Organized broadcasting</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=9" title="Edit section: Organized broadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1244412712"><blockquote class="templatequote"><p>People who weren't around in the Twenties when radio exploded can't know what it meant, this milestone for mankind. Suddenly, with radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for the first time. Music came pouring in. Laughter came in. News came in. The world shrank, with radio.</p><div class="templatequotecite">— <cite><a href="/wiki/Red_Barber" title="Red Barber">Red Barber</a>, sportscaster, <sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup></cite></div></blockquote> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Musical_Concert_by_Wireless_Telephone_(scan)_-_23JUL1912.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Musical_Concert_by_Wireless_Telephone_%28scan%29_-_23JUL1912.jpg/220px-Musical_Concert_by_Wireless_Telephone_%28scan%29_-_23JUL1912.jpg" decoding="async" width="220" height="282" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Musical_Concert_by_Wireless_Telephone_%28scan%29_-_23JUL1912.jpg/330px-Musical_Concert_by_Wireless_Telephone_%28scan%29_-_23JUL1912.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Musical_Concert_by_Wireless_Telephone_%28scan%29_-_23JUL1912.jpg/440px-Musical_Concert_by_Wireless_Telephone_%28scan%29_-_23JUL1912.jpg 2x" data-file-width="531" data-file-height="681" /></a><figcaption>In July 1912, Charles "Doc" Herrold began weekly broadcasts in San Jose, California, using an arc transmitter.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:German_Post_Office_subscription_radio_receiver_1923.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0d/German_Post_Office_subscription_radio_receiver_1923.jpg/260px-German_Post_Office_subscription_radio_receiver_1923.jpg" decoding="async" width="260" height="169" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0d/German_Post_Office_subscription_radio_receiver_1923.jpg/390px-German_Post_Office_subscription_radio_receiver_1923.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0d/German_Post_Office_subscription_radio_receiver_1923.jpg/520px-German_Post_Office_subscription_radio_receiver_1923.jpg 2x" data-file-width="1352" data-file-height="880" /></a><figcaption>Broadcasting in Germany began 1922 as a Post Office monopoly on a subscription basis, using sealed receivers which could only receive one station.</figcaption></figure> <p>Following World War I, the number of stations providing a regular broadcasting service greatly increased, primarily due to advances in vacuum-tube technology. In response to ongoing activities, government regulators eventually codified standards for which stations could make broadcasts intended for the general public, for example, in the United States formal recognition of a "broadcasting service" came with the establishment of regulations effective December 1, 1921,<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> and Canadian authorities created a separate category of "radio-telephone broadcasting stations" in April 1922.<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> However, there were numerous cases of entertainment broadcasts being presented on a regular schedule before their formal recognition by government regulators. Some early examples include: </p> <ul><li><u>July 21, 1912.</u> The first person to transmit entertainment broadcasts on a regular schedule appears to have been Charles "Doc" Herrold, who inaugurated weekly programs, using an arc transmitter, from his Wireless School station in San Jose, California.<sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> The broadcasts continued until the station was shut down due to the entrance of the United States into World War I in April 1917.</li> <li><u>March 28, 1914.</u> The <a href="/wiki/Robert_Goldschmidt#First_European_scheduled_broadcasts" title="Robert Goldschmidt">Laeken station</a> in Belgium, under the oversight of Robert Goldschmidt, inaugurated a weekly series of concerts,<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> transmitted at 5:00 p.m. on Saturdays. These continued for about four months until July, and were ended by the start of World War I.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> In August 1914 the Laeken facilities were destroyed, to keep them from falling into the hands of invading German troops.</li> <li><u>November 1916.</u> De Forest perfected "Oscillion" power vacuum tubes, capable of use in radio transmitters, and inaugurated daily broadcasts of entertainment and news from his New York "Highbridge" station, <a href="/wiki/Radio_2XG" title="Radio 2XG">2XG</a>. This station also suspended operations in April 1917 due to the prohibition of civilian radio transmissions following the United States' entry into World War I.<sup id="cite_ref-Telephony1916_41-0" class="reference"><a href="#cite_note-Telephony1916-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> Its most publicized program was the broadcasting of election results for the <a href="/wiki/1916_United_States_presidential_election" title="1916 United States presidential election">Hughes-Wilson presidential election</a> on November 7, 1916, with updates provided by wire from the <i><a href="/wiki/New_York_American" class="mw-redirect" title="New York American">New York American</a></i> offices. An estimated 7,000 radio listeners as far as 200 miles (320 kilometers) from New York heard election returns interspersed with patriotic music.<sup id="cite_ref-Experimenter1917_42-0" class="reference"><a href="#cite_note-Experimenter1917-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup></li> <li><u>April 17, 1919.</u> Shortly after the end of World War I, F. S. McCullough at the Glenn L. Martin aviation plant in Cleveland, Ohio, began a weekly series of phonograph concerts.<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> However, the broadcasts were soon suspended, due to interference complaints by the U.S. Navy.<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup></li> <li><u>November 6, 1919.</u> The first scheduled (pre-announced in the press) Dutch radio broadcast was made by Nederlandsche Radio Industrie station <a href="/wiki/PCGG" title="PCGG">PCGG</a> at The Hague, which began regular concerts broadcasts. It found it had a large audience outside the Netherlands, mostly in the UK. (Rather than true AM signals, at least initially this station used a form of narrowband FM, which required receivers to be slightly detuned to receive the signals using <a href="/wiki/Detector_(radio)#Frequency_and_phase_modulation_detectors" title="Detector (radio)">slope detection</a>.)<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup></li> <li><u>Late 1919.</u> De Forest's New York station, 2XG, returned to the airwaves in late 1919 after having to suspend operations during World War I.<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> The station continued to operate until early 1920, when it was shut down because the transmitter had been moved to a new location without permission.</li> <li><u>May 20, 1920.</u> Experimental Canadian Marconi station <a href="/wiki/CINW" title="CINW">XWA</a> (later CFCF, deleted in 2010 as CINW) in Montreal began regular broadcasts,<sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> and claims status as the first commercial broadcaster in the world.</li> <li><u>June 1920.</u> De Forest transferred 2XG's former transmitter to San Francisco, California, where it was relicensed as <a href="/wiki/KZY" title="KZY">6XC</a>, the "California Theater station".<sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup> By June 1920 the station began transmitting daily concerts.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup> De Forest later stated that this was the "first radio-telephone station devoted solely" to broadcasting to the public.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup></li> <li><u>August 20, 1920.</u> On this date the <i><a href="/wiki/Detroit_News" class="mw-redirect" title="Detroit News">Detroit News</a></i> began daily transmissions over station <a href="/wiki/WWJ_(AM)" title="WWJ (AM)">8MK</a> (later WWJ), located in the newspaper's headquarters building. The newspaper began extensively publicizing station operations beginning on August 31, 1920, with a special program featuring primary election returns.<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup> Station management later claimed the title of being where "commercial radio broadcasting began".<sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup></li> <li><u>November 2, 1920.</u> Beginning on October 17, 1919,<sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup> Westinghouse engineer <a href="/wiki/Frank_Conrad" title="Frank Conrad">Frank Conrad</a> began broadcasting recorded and live music on a semi-regular schedule from his home station, 8XK in Wilkinsburg, Pennsylvania. This inspired his employer to begin its own ambitious service at the company's headquarters in East Pittsburgh, Pennsylvania. Operations began, initially with the call sign 8ZZ, with an election night program featuring election returns on November 2, 1920.<sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup> As <a href="/wiki/KDKA_(AM)" title="KDKA (AM)">KDKA</a>, the station adopted a daily schedule beginning on December 21, 1920.<sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup> This station is another contender for the title of "first commercial station".</li> <li><u>January 3, 1921.</u> University of Wisconsin - Regular schedule of voice broadcasts begin; 9XM is the first radio station in the United States to provide the weather forecast by voice (January 3). In September, farm market broadcasts are added. On November 1, 9XM carries the first live broadcast of a symphony orchestra—the Cincinnati Symphony Orchestra from the UW Armory using a single microphone.<sup id="cite_ref-56" class="reference"><a href="#cite_note-56"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading3"><h3 id="Radio_networks">Radio networks</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=10" title="Edit section: Radio networks"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Radio_network" title="Radio network">Radio network</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Broadcasting_a_radio_play_at_NBC_studio.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Broadcasting_a_radio_play_at_NBC_studio.jpg/330px-Broadcasting_a_radio_play_at_NBC_studio.jpg" decoding="async" width="330" height="207" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Broadcasting_a_radio_play_at_NBC_studio.jpg/495px-Broadcasting_a_radio_play_at_NBC_studio.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Broadcasting_a_radio_play_at_NBC_studio.jpg/660px-Broadcasting_a_radio_play_at_NBC_studio.jpg 2x" data-file-width="2226" data-file-height="1398" /></a><figcaption>A live radio play being broadcast at NBC studios in New York. Most 1920s through 1940s network programs were broadcast live.</figcaption></figure> <p>Because most longwave radio frequencies were used for international radiotelegraph communication, a majority of early broadcasting stations operated on mediumwave frequencies, whose limited range generally restricted them to local audiences. One method for overcoming this limitation, as well as a method for sharing program costs, was to create radio <a href="/wiki/Radio_network" title="Radio network">networks</a>, linking stations together with telephone lines to provide a nationwide audience. </p> <div class="mw-heading mw-heading4"><h4 id="United_States">United States</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=11" title="Edit section: United States"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In the U.S., the <a href="/wiki/AT%26T" title="AT&T">American Telephone and Telegraph Company</a> (AT&T) was the first organization to create a radio network, and also to promote commercial advertising, which it called "toll" broadcasting. Its flagship station, <a href="/wiki/WFAN_(AM)" title="WFAN (AM)">WEAF</a> (now WFAN) in New York City, sold blocks of airtime to commercial sponsors that developed entertainment shows containing <a href="/wiki/Radio_commercial" class="mw-redirect" title="Radio commercial">commercial messages</a>. AT&T held a monopoly on quality telephone lines, and by 1924 had linked 12 stations in Eastern cities into a "chain". The <a href="/wiki/RCA" title="RCA">Radio Corporation of America</a> (RCA), <a href="/wiki/General_Electric" title="General Electric">General Electric</a>, and <a href="/wiki/Westinghouse_Electric_Corporation" title="Westinghouse Electric Corporation">Westinghouse</a> organized a competing network around its own flagship station, RCA's <a href="/wiki/WABC_(AM)" title="WABC (AM)">WJZ</a> (now WABC) in New York City, but were hampered by AT&T's refusal to lease connecting lines or allow them to sell airtime. In 1926 AT&T sold its radio operations to RCA, which used them to form the nucleus of the new <a href="/wiki/National_Broadcasting_Company" class="mw-redirect" title="National Broadcasting Company">NBC</a> network.<sup id="cite_ref-57" class="reference"><a href="#cite_note-57"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup> By the 1930s, most of the major radio stations in the country were affiliated with networks owned by two companies, NBC and <a href="/wiki/Columbia_Broadcasting_System" class="mw-redirect" title="Columbia Broadcasting System">CBS</a>. In 1934, a third national network, the <a href="/wiki/Mutual_Radio_Network" class="mw-redirect" title="Mutual Radio Network">Mutual Radio Network</a>, was formed as a cooperative owned by its stations. </p> <div class="mw-heading mw-heading4"><h4 id="United_Kingdom">United Kingdom</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=12" title="Edit section: United Kingdom"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:BBC_receiver_license_1923.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f3/BBC_receiver_license_1923.jpg/325px-BBC_receiver_license_1923.jpg" decoding="async" width="325" height="235" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f3/BBC_receiver_license_1923.jpg/488px-BBC_receiver_license_1923.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f3/BBC_receiver_license_1923.jpg/650px-BBC_receiver_license_1923.jpg 2x" data-file-width="2984" data-file-height="2156" /></a><figcaption>A BBC receiver licence from 1922. The British government required listeners to purchase yearly licences, which financed the stations.</figcaption></figure> <p>A second country which quickly adopted network programming was the United Kingdom, and its national network quickly became a prototype for a state-managed monopoly of broadcasting.<sup id="cite_ref-Hilmes_58-0" class="reference"><a href="#cite_note-Hilmes-58"><span class="cite-bracket">[</span>58<span class="cite-bracket">]</span></a></sup> A rising interest in radio broadcasting by the British public pressured the government to reintroduce the service, following its suspension in 1920. However, the government also wanted to avoid what it termed the "chaotic" U.S. experience of allowing large numbers of stations to operate with few restrictions. There were also concerns about broadcasting becoming dominated by the Marconi company.<sup id="cite_ref-59" class="reference"><a href="#cite_note-59"><span class="cite-bracket">[</span>59<span class="cite-bracket">]</span></a></sup> Arrangements were made for six large radio manufacturers to form a consortium, the <a href="/wiki/British_Broadcasting_Company" title="British Broadcasting Company">British Broadcasting Company</a> (BBC), established on 18 October 1922, which was given a monopoly on broadcasting. This enterprise was supported by a tax on radio sets sales, plus an annual license fee on receivers, collected by the Post Office.<sup id="cite_ref-Street2_60-0" class="reference"><a href="#cite_note-Street2-60"><span class="cite-bracket">[</span>60<span class="cite-bracket">]</span></a></sup> Initially the eight stations were allowed regional autonomy. In 1927, the original broadcasting organization was replaced by a government chartered <a href="/wiki/British_Broadcasting_Corporation" class="mw-redirect" title="British Broadcasting Corporation">British Broadcasting Corporation</a>.<sup id="cite_ref-Street3_61-0" class="reference"><a href="#cite_note-Street3-61"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> an independent nonprofit supported solely by a 10 shilling <a href="/wiki/Receiver_license" class="mw-redirect" title="Receiver license">receiver license</a> fee.<sup id="cite_ref-Street3_61-1" class="reference"><a href="#cite_note-Street3-61"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> Both highbrow and mass-appeal programmes were carried by the <a href="/wiki/BBC_National_Programme" title="BBC National Programme">National</a> and <a href="/wiki/BBC_Regional_Programme" title="BBC Regional Programme">Regional</a> networks. </p> <div class="mw-heading mw-heading3"><h3 id=""Golden_Age_of_Radio""><span id=".22Golden_Age_of_Radio.22"></span>"Golden Age of Radio"</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=13" title="Edit section: "Golden Age of Radio""><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Golden_Age_of_Radio" title="Golden Age of Radio">Golden Age of Radio</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png/330px-Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png" decoding="async" width="330" height="257" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png/495px-Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png/660px-Radio_copyright_problem_cartoon_-_Radio_News_May_1925.png 2x" data-file-width="702" data-file-height="547" /></a><figcaption>When broadcasting began in 1920, music was played on air without regard to its copyright status. Music publishers challenged this practice as being copyright infringement, which for a time kept many popular tunes off the air, and this 1925 U.S. editorial cartoon shows a rich publisher muzzling two radio performers. The radio industry eventually agreed to make royalty payments.</figcaption></figure> <p>The period from the early 1920s through the 1940s is often called the "Golden Age of Radio". During this period AM radio was the main source of home entertainment, until it was replaced by television. For the first time entertainment was provided from outside the home, replacing traditional forms of entertainment such as oral storytelling and music from family members. New forms were created, including <a href="/wiki/Radio_play" class="mw-redirect" title="Radio play">radio plays</a>, mystery serials, <a href="/wiki/Soap_opera" title="Soap opera">soap operas</a>, <a href="/wiki/Quiz_show" class="mw-redirect" title="Quiz show">quiz shows</a>, <a href="/wiki/Variety_show" title="Variety show">variety hours</a>, <a href="/wiki/Situation_comedy" class="mw-redirect" title="Situation comedy">situation comedies</a> and <a href="/wiki/Children%27s_show" class="mw-redirect" title="Children's show">children's shows</a>. Radio news, including remote reporting, allowed listeners to be vicariously present at notable events. </p><p>Radio greatly eased the isolation of rural life. Political officials could now speak directly to millions of citizens. One of the first to take advantage of this was American president <a href="/wiki/Franklin_Roosevelt" class="mw-redirect" title="Franklin Roosevelt">Franklin Roosevelt</a>, who became famous for his <a href="/wiki/Fireside_chats" title="Fireside chats">fireside chats</a> during the <a href="/wiki/Great_Depression" title="Great Depression">Great Depression</a>. However, broadcasting also provided the means to use <a href="/wiki/Propaganda" title="Propaganda">propaganda</a> as a powerful government tool, and contributed to the rise of <a href="/wiki/Fascist" class="mw-redirect" title="Fascist">fascist</a> and <a href="/wiki/Communist" class="mw-redirect" title="Communist">communist</a> ideologies. </p> <div class="mw-heading mw-heading3"><h3 id="Decline_in_popularity">Decline in popularity</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=14" title="Edit section: Decline in popularity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In the 1940s two new broadcast media, <a href="/wiki/FM_broadcasting" title="FM broadcasting">FM radio</a> and <a href="/wiki/Television" title="Television">television</a>, began to provide extensive competition with the established broadcasting services. The AM radio industry suffered a serious loss of audience and advertising revenue, and coped by developing new strategies. Network broadcasting gave way to <a href="/wiki/Radio_format" title="Radio format">format</a> broadcasting: instead of broadcasting the same programs all over the country, stations individually adopted specialized formats which appealed to different audiences, such as regional and local news, sports, "talk" programs, and programs targeted at minorities. Instead of live music, most stations began playing less expensive recorded music. </p><p>In the late 1960s and 1970s, top 40 rock and roll stations in the U.S. and Canada such as <a href="/wiki/WABC_(AM)" title="WABC (AM)">WABC</a> and <a href="/wiki/CHUM_(AM)" title="CHUM (AM)">CHUM</a> transmitted highly processed and extended audio to 11 kHz, successfully attracting huge audiences. For young people, listening to AM broadcasts and participating in their music surveys and contests was the social media of the time. </p><p>In the late 1970s, spurred by the exodus of musical programming to FM stations, the AM radio industry in the United States developed technology for broadcasting in <a href="/wiki/Stereophonic_sound" title="Stereophonic sound">stereo</a>. Other nations adopted AM stereo, most commonly choosing Motorola's C-QUAM, and in 1993 the United States also made the C-QUAM system its standard, after a period allowing four different standards to compete. The selection of a single standard improved acceptance of <a href="/wiki/AM_stereo" title="AM stereo">AM stereo</a>,<sup id="cite_ref-stereo_62-0" class="reference"><a href="#cite_note-stereo-62"><span class="cite-bracket">[</span>62<span class="cite-bracket">]</span></a></sup> however overall there was limited adoption of AM stereo worldwide, and interest declined after 1990. With the continued migration of AM stations away from music to news, sports, and talk formats, receiver manufacturers saw little reason to adopt the more expensive stereo tuners, and thus radio stations have little incentive to upgrade to stereo transmission. </p><p>In countries where the use of directional antennas is common, such as the United States, transmitter sites consisting of multiple towers often occupy large tracts of land that have significantly increased in value over the decades, to the point that the value of land exceeds that of the station itself. This sometimes results in the sale of the transmitter site, with the station relocating to a more distant shared site using significantly less power,<sup id="cite_ref-63" class="reference"><a href="#cite_note-63"><span class="cite-bracket">[</span>63<span class="cite-bracket">]</span></a></sup> or completely shutting down operations.<sup id="cite_ref-64" class="reference"><a href="#cite_note-64"><span class="cite-bracket">[</span>64<span class="cite-bracket">]</span></a></sup> </p><p>The ongoing development of alternative transmission systems, including Digital Audio Broadcasting (DAB), satellite radio, and HD (digital) radio, continued the decline of the popularity of the traditional broadcast technologies. These new options, including the introduction of Internet streaming, particularly resulted in the reduction of shortwave transmissions, as international broadcasters found ways to reach their audiences more easily.<sup id="cite_ref-65" class="reference"><a href="#cite_note-65"><span class="cite-bracket">[</span>65<span class="cite-bracket">]</span></a></sup> </p><p>In 2022 it was reported that AM radio was being removed from a number of <a href="/wiki/Electric_vehicle" title="Electric vehicle">electric vehicle</a> (EV) models, including from cars manufactured by Tesla, Audi, Porsche, BMW and Volvo, reportedly due to automakers concerns that an EV's higher electromagnetic interference can disrupt the reception of AM transmissions and hurt the listening experience, among other reasons.<sup id="cite_ref-66" class="reference"><a href="#cite_note-66"><span class="cite-bracket">[</span>66<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-67" class="reference"><a href="#cite_note-67"><span class="cite-bracket">[</span>67<span class="cite-bracket">]</span></a></sup> However the United States Congress has introduced a bill to require all vehicles sold in the US to have an AM receiver to receive emergency broadcasts.<sup id="cite_ref-68" class="reference"><a href="#cite_note-68"><span class="cite-bracket">[</span>68<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="AM_band_revitalization_efforts_in_the_United_States">AM band revitalization efforts in the United States</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=15" title="Edit section: AM band revitalization efforts in the United States"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The FM broadcast band was established in 1941 in the United States, and at the time some suggested that the AM band would soon be eliminated. In 1948 wide-band FM's inventor, <a href="/wiki/Edwin_Howard_Armstrong" title="Edwin Howard Armstrong">Edwin H. Armstrong</a>, predicted that "The broadcasters will set up FM stations which will parallel, carry the same program, as over their AM stations... eventually the day will come, of course, when we will no longer have to build receivers capable of receiving both types of transmission, and then the AM transmitters will disappear."<sup id="cite_ref-69" class="reference"><a href="#cite_note-69"><span class="cite-bracket">[</span>69<span class="cite-bracket">]</span></a></sup> However, FM stations actually struggled for many decades, and it was not until 1978 that FM listenership surpassed that of AM stations. Since then the AM band's share of the audience has continued to decline. </p> <div class="mw-heading mw-heading3"><h3 id="Fairness_Doctrine_repeal">Fairness Doctrine repeal</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=16" title="Edit section: Fairness Doctrine repeal"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Fairness_Doctrine#Revocation" class="mw-redirect" title="Fairness Doctrine">Fairness Doctrine § Revocation</a></div> <p>In 1987, the elimination of the <a href="/wiki/Fairness_Doctrine" class="mw-redirect" title="Fairness Doctrine">Fairness Doctrine</a> requirement meant that talk shows, which were commonly carried by AM stations, could adopt a more focused presentation on controversial topics, without the distraction of having to provide airtime for any contrasting opinions. In addition, satellite distribution made it possible for programs to be economically carried on a national scale. The introduction of nationwide talk shows, most prominently <a href="/wiki/Rush_Limbaugh" title="Rush Limbaugh">Rush Limbaugh</a>'s beginning in 1988, was sometimes credited with "saving" AM radio.<sup id="cite_ref-70" class="reference"><a href="#cite_note-70"><span class="cite-bracket">[</span>70<span class="cite-bracket">]</span></a></sup> However, these stations tended to attract older listeners who were of lesser interest to advertisers, and AM radio's audience share continued to erode. </p> <div class="mw-heading mw-heading3"><h3 id="AM_stereo_and_AMAX_standards">AM stereo and AMAX standards</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=17" title="Edit section: AM stereo and AMAX standards"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/AM_stereo#Adoption_in_the_United_States" title="AM stereo">AM stereo § Adoption in the United States</a>, and <a href="/wiki/AMAX" title="AMAX">AMAX</a></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:AMAX_radio_receiver_certification_logo.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/eb/AMAX_radio_receiver_certification_logo.gif/200px-AMAX_radio_receiver_certification_logo.gif" decoding="async" width="200" height="111" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/eb/AMAX_radio_receiver_certification_logo.gif/300px-AMAX_radio_receiver_certification_logo.gif 1.5x, //upload.wikimedia.org/wikipedia/commons/e/eb/AMAX_radio_receiver_certification_logo.gif 2x" data-file-width="350" data-file-height="194" /></a><figcaption>Radios meeting the AMAX standards could display a certification logo, with the "stereo" notation reserved for those capable of AM stereo reception</figcaption></figure> <p>In 1961, the FCC adopted a single standard for FM stereo transmissions, which was widely credited with enhancing FM's popularity. Developing the technology for AM broadcasting in stereo was challenging due to the need to limit the transmissions to a 20 kHz bandwidth, while also making the transmissions backward compatible with existing non-stereo receivers. </p><p>In 1990, the FCC authorized an AM stereo standard developed by Magnavox, but two years later revised its decision to instead approve four competing implementations, saying it would "let the marketplace decide" which was best.<sup id="cite_ref-stereo_62-1" class="reference"><a href="#cite_note-stereo-62"><span class="cite-bracket">[</span>62<span class="cite-bracket">]</span></a></sup> The lack of a common standard resulted in consumer confusion and increased the complexity and cost of producing AM stereo receivers. </p><p>In 1993, the FCC again revised its policy, by selecting <a href="/wiki/C-QUAM" title="C-QUAM">C-QUAM</a> as the sole AM stereo implementation. In 1993, the FCC also endorsed, although it did not make mandatory, <a href="/wiki/AMAX" title="AMAX">AMAX</a> broadcasting standards that were developed by the <a href="/wiki/Electronic_Industries_Alliance" title="Electronic Industries Alliance">Electronic Industries Association</a> (EIA) and the <a href="/wiki/National_Association_of_Broadcasters" title="National Association of Broadcasters">National Association of Broadcasters</a> (NAB) with the intention of helping AM stations, especially ones with musical formats, become more competitive with FM broadcasters by promoting better quality receivers. However, the stereo AM and AMAX initiatives had little impact, and a 2015 review of these events concluded that </p> <blockquote><p>Initially the consumer manufacturers made a concerted attempt to specify performance of AM receivers through the 1993 AMAX standard, a joint effort of the EIA and the NAB, with FCC backing... The FCC rapidly followed up on this with codification of the CQUAM AM stereo standard, also in 1993. At this point, the stage appeared to be set for rejuvenation of the AM band. Nevertheless, with the legacy of confusion and disappointment in the rollout of the multiple incompatible AM stereo systems, and failure of the manufacturers (including the auto makers) to effectively promote AMAX radios, coupled with the ever-increasing background of noise in the band, the general public soon lost interest and moved on to other media.<sup id="cite_ref-71" class="reference"><a href="#cite_note-71"><span class="cite-bracket">[</span>71<span class="cite-bracket">]</span></a></sup></p></blockquote> <div class="mw-heading mw-heading3"><h3 id="Expanded_band">Expanded band</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=18" title="Edit section: Expanded band"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/AM_expanded_band#United_States" title="AM expanded band">AM expanded band § United States</a></div> <p>On June 8, 1988, an <a href="/wiki/International_Telecommunication_Union" title="International Telecommunication Union">International Telecommunication Union</a> (ITU)-sponsored conference held at Rio de Janeiro, Brazil adopted provisions, effective July 1, 1990, to extend the upper end of the Region 2 AM broadcast band, by adding ten frequencies which spanned from 1610 kHz to 1700 kHz.<sup id="cite_ref-72" class="reference"><a href="#cite_note-72"><span class="cite-bracket">[</span>72<span class="cite-bracket">]</span></a></sup> At this time it was suggested that as many as 500 U.S. stations could be assigned to the new frequencies.<sup id="cite_ref-73" class="reference"><a href="#cite_note-73"><span class="cite-bracket">[</span>73<span class="cite-bracket">]</span></a></sup> </p><p>On April 12, 1990, the FCC voted to begin the process of populating the expanded band, with the main priority being the reduction of interference on the existing AM band, by transferring selected stations to the new frequencies. It was now estimated that the expanded band could accommodate around 300 U.S. stations.<sup id="cite_ref-74" class="reference"><a href="#cite_note-74"><span class="cite-bracket">[</span>74<span class="cite-bracket">]</span></a></sup> However, it turned out that the number of possible station reassignments was much lower, with a 2006 accounting reporting that, out of 4,758 licensed U.S. AM stations, only 56 were now operating on the expanded band.<sup id="cite_ref-75" class="reference"><a href="#cite_note-75"><span class="cite-bracket">[</span>75<span class="cite-bracket">]</span></a></sup> Moreover, despite an initial requirement that by the end of five years either the original station or its expanded band counterpart had to cease broadcasting,<sup id="cite_ref-76" class="reference"><a href="#cite_note-76"><span class="cite-bracket">[</span>76<span class="cite-bracket">]</span></a></sup> as of 2015 there were 25 cases where the original standard band station was still on the air, despite also operating as an expanded band station. </p> <div class="mw-heading mw-heading3"><h3 id="HD_radio">HD radio</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=19" title="Edit section: HD radio"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/HD_Radio" title="HD Radio">HD Radio</a></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Hdradio-logo.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Hdradio-logo.svg/200px-Hdradio-logo.svg.png" decoding="async" width="200" height="66" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Hdradio-logo.svg/300px-Hdradio-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Hdradio-logo.svg/400px-Hdradio-logo.svg.png 2x" data-file-width="512" data-file-height="170" /></a><figcaption></figcaption></figure> <p>HD Radio is a digital audio broadcasting method developed by <a href="/wiki/IBiquity" title="IBiquity">iBiquity</a>. In 2002 its "hybrid mode", which simultaneously transmits a standard analog signal as well as a digital one, was approved by the FCC for use by AM stations, initially only during daytime hours, due to concerns that during the night its wider bandwidth would cause unacceptable interference to stations on adjacent frequencies.<sup id="cite_ref-77" class="reference"><a href="#cite_note-77"><span class="cite-bracket">[</span>77<span class="cite-bracket">]</span></a></sup> In 2007 nighttime operation was also authorized.<sup id="cite_ref-78" class="reference"><a href="#cite_note-78"><span class="cite-bracket">[</span>78<span class="cite-bracket">]</span></a></sup> </p><p>The number of hybrid mode AM stations is not exactly known, because the FCC does not keep track of the stations employing the system, and some authorized stations have later turned it off. But as of 2020 the commission estimated that fewer than 250 AM stations were transmitting hybrid mode signals.<sup id="cite_ref-79" class="reference"><a href="#cite_note-79"><span class="cite-bracket">[</span>79<span class="cite-bracket">]</span></a></sup> On October 27, 2020, the FCC voted to allow AM stations to eliminate their analog transmissions and convert to all-digital operation, with the requirement that stations making the change had to continue to make programming available over "at least one free over-the-air digital programming stream that is comparable to or better in audio quality than a standard analog broadcast".<sup id="cite_ref-80" class="reference"><a href="#cite_note-80"><span class="cite-bracket">[</span>80<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="FM_translator_stations">FM translator stations</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=20" title="Edit section: FM translator stations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Broadcast_relay_station#United_States" title="Broadcast relay station">Broadcast relay station § United States</a></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:WCHL_2017.png" class="mw-file-description"><img alt="right" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/WCHL_2017.png/200px-WCHL_2017.png" decoding="async" width="200" height="155" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/WCHL_2017.png/300px-WCHL_2017.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/02/WCHL_2017.png/400px-WCHL_2017.png 2x" data-file-width="3300" data-file-height="2550" /></a><figcaption>Many U.S. AM stations no longer publicize their AM signals, instead promoting simulcasts by FM band translators and Internet streams.<sup id="cite_ref-81" class="reference"><a href="#cite_note-81"><span class="cite-bracket">[</span>81<span class="cite-bracket">]</span></a></sup></figcaption></figure> <p>Despite the various actions, AM band audiences continued to contract, and the number of stations began to slowly decline. A 2009 FCC review reported that "The story of AM radio over the last 50 years has been a transition from being the dominant form of audio entertainment for all age groups to being almost non-existent to the youngest demographic groups. Among persons aged 12–24, AM accounts for only 4% of listening, while FM accounts for 96%. Among persons aged 25–34, AM accounts for only 9% of listening, while FM accounts for 91%. The median age of listeners to the AM band is 57 years old, a full generation older than the median age of FM listeners."<sup id="cite_ref-FCC_auth_82-0" class="reference"><a href="#cite_note-FCC_auth-82"><span class="cite-bracket">[</span>82<span class="cite-bracket">]</span></a></sup> </p><p>In 2009, the FCC made a major regulatory change, when it adopted a policy allowing AM stations to simulcast over FM translator stations. Translators had previously been available only to FM broadcasters, in order to increase coverage in fringe areas. Their assignment for use by AM stations was intended to approximate the station's daytime coverage, which in cases where the stations reduced power at night, often resulted in expanded nighttime coverage. Although the translator stations are not permitted to originate programming when the "primary" AM station is broadcasting, they are permitted to do so during nighttime hours for AM stations licensed for daytime-only operation.<sup id="cite_ref-OK_83-0" class="reference"><a href="#cite_note-OK-83"><span class="cite-bracket">[</span>83<span class="cite-bracket">]</span></a></sup> </p><p>Prior to the adoption of the new policy, as of March 18, 2009, the FCC had issued 215 Special Temporary Authority grants for FM translators relaying AM stations.<sup id="cite_ref-OK_83-1" class="reference"><a href="#cite_note-OK-83"><span class="cite-bracket">[</span>83<span class="cite-bracket">]</span></a></sup> After creation of the new policy, by 2011 there were approximately 500 in operation,<sup id="cite_ref-84" class="reference"><a href="#cite_note-84"><span class="cite-bracket">[</span>84<span class="cite-bracket">]</span></a></sup> and as of 2020 approximately 2,800 of the 4,570 licensed AM stations were rebroadcasting on one or more FM translators.<sup id="cite_ref-worry_85-0" class="reference"><a href="#cite_note-worry-85"><span class="cite-bracket">[</span>85<span class="cite-bracket">]</span></a></sup> In 2009 the FCC stated that "We do not intend to allow these cross-service translators to be used as surrogates for FM stations".<sup id="cite_ref-FCC_auth_82-1" class="reference"><a href="#cite_note-FCC_auth-82"><span class="cite-bracket">[</span>82<span class="cite-bracket">]</span></a></sup> However, based on station slogans, especially in the case of recently adopted musical formats, in most cases the expectation is that listeners will primarily be tuning into the FM signal rather than the nominally "primary" AM station. A 2020 review noted that "for many owners, keeping their AM stations on the air now is pretty much just about retaining their FM translator footprint rather than keeping the AM on the air on its own merits".<sup id="cite_ref-worry_85-1" class="reference"><a href="#cite_note-worry-85"><span class="cite-bracket">[</span>85<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Additional_activities">Additional activities</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=21" title="Edit section: Additional activities"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 2018 the FCC, led by then-Commission Chairman <a href="/wiki/Ajit_Pai" title="Ajit Pai">Ajit Pai</a>, proposed greatly reducing signal protection for 50 kW Class A "<a href="/wiki/Clear-channel_station" title="Clear-channel station">clear channel</a>" stations. This would allow co-channel secondary stations to operate with higher powers, especially at night. However, the <a href="/wiki/Federal_Emergency_Management_Agency" title="Federal Emergency Management Agency">Federal Emergency Management Agency</a> (FEMA) expressed concerns that this would reduce the effectiveness of emergency communications.<sup id="cite_ref-86" class="reference"><a href="#cite_note-86"><span class="cite-bracket">[</span>86<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Electric_vehicles">Electric vehicles</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=22" title="Edit section: Electric vehicles"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In May 2023, a bipartisan group of lawmakers in the United States introduced legislation making it illegal for automakers to eliminate AM radio from their cars. The lawmakers argue that AM radio is an important tool for public safety due to being a component of the <a href="/wiki/Emergency_Alert_System" title="Emergency Alert System">Emergency Alert System</a> (EAS). Some automakers have been eliminating AM radio from their <a href="/wiki/Electric_vehicles" class="mw-redirect" title="Electric vehicles">electric vehicles</a> (EVs) due to interference from the <a href="/wiki/Traction_motor" title="Traction motor">electric motors</a>, but the lawmakers argue that this is a safety risk and that car owners should have access to AM radio regardless of the type of vehicle they drive. The proposed legislation would require all new vehicles to include AM radio at no additional charge, and it would also require automakers that have already eliminated AM radio to inform customers of alternatives.<sup id="cite_ref-87" class="reference"><a href="#cite_note-87"><span class="cite-bracket">[</span>87<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Technical_information">Technical information</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=23" title="Edit section: Technical information"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>AM radio technology is simpler than later transmission systems. An AM receiver detects amplitude variations in the <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">radio waves</a> at a particular frequency, then amplifies changes in the signal <a href="/wiki/Voltage" title="Voltage">voltage</a> to operate a <a href="/wiki/Loudspeaker" title="Loudspeaker">loudspeaker</a> or <a href="/wiki/Earphone" class="mw-redirect" title="Earphone">earphone</a>. However, the simplicity of AM transmission also makes it vulnerable to "static" (<a href="/wiki/Radio_noise" title="Radio noise">radio noise</a>, <a href="/wiki/Radio_frequency_interference" class="mw-redirect" title="Radio frequency interference">radio frequency interference</a>) created by both natural atmospheric electrical activity such as lightning, and electrical and electronic equipment, including fluorescent lights, motors and vehicle ignition systems. In large urban centers, AM radio signals can be severely disrupted by metal structures and tall buildings. As a result, AM radio tends to do best in areas where <a href="/wiki/FM_broadcast_band" title="FM broadcast band">FM frequencies</a> are in short supply, or in thinly populated or mountainous areas where FM coverage is poor. Great care must be taken to avoid mutual interference between stations operating on the same frequency. In general, an AM transmission needs to be about 20 times stronger than an interfering signal to avoid a reduction in quality, in contrast to FM signals, where the "<a href="/wiki/Capture_effect" title="Capture effect">capture effect</a>" means that the dominant signal needs to only be about twice as strong as the interfering one. </p><p>To allow room for more stations on the mediumwave broadcast band in the United States, in June 1989 the FCC adopted a <a href="/wiki/National_Radio_Systems_Committee" title="National Radio Systems Committee">National Radio Systems Committee</a> (NRSC) standard that limited maximum transmitted audio <a href="/wiki/Bandwidth_(signal_processing)" title="Bandwidth (signal processing)">bandwidth</a> to 10.2 kHz, limiting occupied bandwidth to 20.4 kHz. The former audio limitation was 15 kHz resulting in <a href="/wiki/Bandwidth_(signal_processing)" title="Bandwidth (signal processing)">bandwidth</a> of 30 kHz. Another common limitation on AM fidelity is the result of receiver design, although some efforts have been made to improve this, notably through the <a href="/wiki/AMAX" title="AMAX">AMAX</a> standards adopted in the United States. </p> <div class="mw-heading mw-heading3"><h3 id="Broadcast_band_frequencies">Broadcast band frequencies</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=24" title="Edit section: Broadcast band frequencies"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>AM broadcasts are used on several frequency bands. The allocation of these bands is governed by the <a href="/wiki/International_Telecommunication_Union" title="International Telecommunication Union">ITU</a>'s <a href="/wiki/Radio_Regulations" class="mw-redirect" title="Radio Regulations">Radio Regulations</a> and, on the national level, by each country's telecommunications administration (the FCC in the U.S., for example) subject to international agreements. </p><p>The frequency ranges given here are those that are allocated to stations. Because of the bandwidth taken up by the <a href="/wiki/Sideband" title="Sideband">sidebands</a>, the range allocated for the band as a whole is usually about 5 kHz wider on either side. </p><p><span class="anchor" id="AM_longwave_band"></span> </p> <div class="mw-heading mw-heading4"><h4 id="Longwave_broadcasting">Longwave broadcasting</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=25" title="Edit section: Longwave broadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><i><a href="/wiki/Longwave" title="Longwave">Longwave</a></i> (also known as <a href="/wiki/Low_frequency" title="Low frequency">Low frequency</a> (LF)) (148.5 <a href="/wiki/Kilohertz" class="mw-redirect" title="Kilohertz">kHz</a> – 283.5 kHz) Broadcasting stations in this band are assigned transmitting frequencies in the range 153 kHz – 279 kHz, and generally maintain 9 kHz spacing. Longwave assignments for broadcasting only exist in <a href="/wiki/ITU_region" class="mw-redirect" title="ITU region">ITU Region 1</a> (Europe, Africa, and northern and central Asia) and are not allocated elsewhere. Individual stations have coverage measured in the hundreds of kilometers; however, there is only a very limited number of available broadcasting slots. </p><p>Most of the earliest broadcasting experiments took place on <a href="/wiki/Longwave" title="Longwave">longwave</a> frequencies; however, complaints about interference from existing services, particularly the military, led to most broadcasting moving to higher frequencies. </p> <div class="mw-heading mw-heading4"><h4 id="Medium-wave_broadcasting">Medium-wave broadcasting<span class="anchor" id="commercial_AM_bands"></span></h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=26" title="Edit section: Medium-wave broadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><i><a href="/wiki/Medium_wave" title="Medium wave">Medium wave</a></i> (also known as <a href="/wiki/Medium_frequency" title="Medium frequency">Medium frequency</a> (MF)), is by far the most commonly used AM broadcasting band. In ITU Regions 1 and 3, transmitting frequencies run from 531 kHz – 1602 kHz, with 9 kHz spacing (526.5 kHz – 1606.5 kHz), and in ITU Region 2 (the Americas), transmitting frequencies are 530 kHz – 1700 kHz, using 10 kHz spacing (525 kHz – 1705 kHz), including the ITU <a href="/wiki/AM_expanded_band" title="AM expanded band">Extended AM broadcast band</a>, authorized in Region 2, between 1605 kHz and 1705 kHz, previously used for police radio.<sup id="cite_ref-88" class="reference"><a href="#cite_note-88"><span class="cite-bracket">[</span>88<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Shortwave_broadcasting">Shortwave broadcasting</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=27" title="Edit section: Shortwave broadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><i><a href="/wiki/Shortwave" class="mw-redirect" title="Shortwave">Shortwave</a></i> (also known as <a href="/wiki/High_frequency" title="High frequency">High frequency</a> (HF)) transmissions range from approximately 2.3 to 26.1 MHz, divided into 14 broadcast bands. Shortwave broadcasts generally use a narrow 5 kHz channel spacing. Shortwave is used by audio services intended to be heard at great distances from the transmitting station. The long range of shortwave broadcasts comes at the expense of lower <a href="/wiki/High_fidelity" title="High fidelity">audio fidelity</a>. </p><p>Most broadcast services use AM transmissions, although some use a modified version of AM such as <a href="/wiki/Single-sideband_modulation" title="Single-sideband modulation">Single-sideband modulation</a> (SSB) or an AM-compatible version of SSB such as "SSB with carrier reinserted". </p> <div class="mw-heading mw-heading4"><h4 id="VHF_AM_broadcasting">VHF AM broadcasting</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=28" title="Edit section: VHF AM broadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Beginning in the mid-1930s, the United States evaluated options for the establishment of broadcasting stations using much higher transmitting frequencies. In October 1937, the FCC announced a second band of AM stations, consisting of 75 channels spanning from 41.02 to 43.98 MHz, which were informally called <i><a href="/wiki/Apex_(radio_band)" title="Apex (radio band)">Apex</a></i>. </p><p>The 40 kHz spacing between adjacent frequencies was four times that of the 10 kHz spacing used on the standard AM broadcast band, which reduced adjacent-frequency interference, and provided more bandwidth for high-fidelity programming. However, this band was eliminated effective 1 January 1941, after the FCC determined that establishing a band of FM stations was preferable.<sup id="cite_ref-89" class="reference"><a href="#cite_note-89"><span class="cite-bracket">[</span>89<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Other_distribution_methods">Other distribution methods</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=29" title="Edit section: Other distribution methods"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Carrier_current" title="Carrier current">Carrier current</a></div> <p>Beginning in the mid-1930s, starting with "<a href="/wiki/WBRU#Beginnings" title="WBRU">The Brown Network</a>" at Brown University in Providence, Rhode Island, a very low power broadcasting method known as <a href="/wiki/Carrier_current" title="Carrier current">carrier current</a> was developed, and mostly adopted on U.S. college campuses. In this approach AM broadcast signals are distributed over electric power lines, which radiate a signal receivable at a short distance from the lines.<sup id="cite_ref-90" class="reference"><a href="#cite_note-90"><span class="cite-bracket">[</span>90<span class="cite-bracket">]</span></a></sup> In Switzerland a system known as "wire broadcasting" (<i>Telefonrundspruch</i> in German) transmitted AM signals over telephone lines in the <a href="/wiki/Longwave" title="Longwave">longwave</a> band until 1998, when it was shut down.<sup id="cite_ref-91" class="reference"><a href="#cite_note-91"><span class="cite-bracket">[</span>91<span class="cite-bracket">]</span></a></sup> In the UK, <a href="/wiki/Rediffusion" title="Rediffusion">Rediffusion</a> was an early pioneer of AM radio cable distribution. </p><p>Hybrid digital broadcast systems, which combine (mono analog) AM transmission with digital sidebands, have started to be used around the world. In the United States, <a href="/wiki/IBiquity" title="IBiquity">iBiquity</a>'s proprietary <a href="/wiki/HD_Radio" title="HD Radio">HD Radio</a> has been adopted and approved by the FCC for medium wave transmissions,<sup id="cite_ref-92" class="reference"><a href="#cite_note-92"><span class="cite-bracket">[</span>92<span class="cite-bracket">]</span></a></sup> while <a href="/wiki/Digital_Radio_Mondiale" title="Digital Radio Mondiale">Digital Radio Mondiale</a> is a more open effort often used on the <a href="/wiki/Shortwave_bands" title="Shortwave bands">shortwave bands</a>, and can be used alongside many AM broadcasts. Both of these standards are capable of broadcasting audio of significantly greater fidelity than that of standard AM with current bandwidth limitations, and a theoretical frequency response of 0–16 kHz, in addition to stereo sound and text data. </p> <div class="mw-heading mw-heading3"><h3 id="Microbroadcasting">Microbroadcasting</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=AM_broadcasting&action=edit&section=30" title="Edit section: Microbroadcasting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Low-power_broadcasting" title="Low-power broadcasting">Low-power broadcasting</a></div> <p>Some <a href="/wiki/Microbroadcasting" title="Microbroadcasting">microbroadcasters</a>, especially those in the United States operating under the FCC's <a href="/wiki/Part_15" class="mw-redirect" title="Part 15">Part 15</a> rules,<sup id="cite_ref-93" class="reference"><a href="#cite_note-93"><span class="cite-bracket">[</span>93<span class="cite-bracket">]</span></a></sup> and <a href="/wiki/Pirate_radio" title="Pirate radio">pirate radio</a> operators on mediumwave and shortwave, achieve greater range than possible on the <a href="/wiki/FM_broadcast_band" title="FM broadcast band">FM band</a>. On mediumwave these stations often transmit on 1610 kHz to 1710 kHz. Hobbyists also use low-power AM (LPAM) transmitters to provide programming for vintage radio equipment in areas where AM programming is not widely available or does not carry programming the listener desires; in such cases the transmitter, which is designed to cover only the immediate property and perhaps nearby areas, is connected to a computer, an FM radio or an MP3 player. Microbroadcasting and pirate radio have generally been supplanted by streaming audio on the Internet, but some schools and hobbyists still use LPAM transmissions. </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=AM_broadcasting&action=edit&section=31" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Digital_Radio_Mondiale" title="Digital Radio Mondiale">Digital Radio Mondiale</a> (DRM), a digital radio method using the bands LW, MW, SW, and the VHF bands</li> <li><a href="/wiki/Amplitude_modulation" title="Amplitude modulation">Amplitude modulation</a></li> <li><a href="/wiki/Amplitude_Modulation_Signalling_System" class="mw-redirect" title="Amplitude Modulation Signalling System">Amplitude Modulation Signalling System</a>, a digital system for adding low bitrate information to an AM broadcast signal</li> <li><a href="/wiki/CAM-D" title="CAM-D">CAM-D</a>, a hybrid digital radio format for AM broadcasting</li> <li><a href="/wiki/Effective_radiated_power" title="Effective radiated power">Effective radiated power</a> (ERP), standardised definition of radio frequency power</li> <li><a href="/wiki/AM_expanded_band" title="AM expanded band">Extended AM broadcast band</a></li> <li><a href="/wiki/History_of_radio" title="History of radio">History of radio</a></li> <li><a href="/wiki/List_of_50_kW_AM_radio_stations_in_the_United_States" title="List of 50 kW AM radio stations in the United States">List of 50 kW AM radio stations in the United States</a></li> <li><a href="/wiki/Lists_of_radio_stations_in_North_America" class="mw-redirect" title="Lists of radio stations in North America">Lists of radio stations in North America</a></li> <li><a href="/wiki/List_of_oldest_radio_stations" title="List of oldest radio stations">Oldest radio stations</a></li> <li><a href="/wiki/MW_DX" title="MW DX">MW DXing</a>, the hobby of receiving distant AM radio stations on the mediumwave band.</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=AM_broadcasting&action=edit&section=32" 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"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.wfmynews2.com/article/news/verify/verify-why-does-am-radio-sound-worse-than-fm/83-489480515">"VERIFY: Why Does AM Radio Sound Worse Than FM?"</a>. <i>wfmynews2.com</i>. November 6, 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">2022-12-29</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=wfmynews2.com&rft.atitle=VERIFY%3A+Why+Does+AM+Radio+Sound+Worse+Than+FM%3F&rft.date=2017-11-06&rft_id=https%3A%2F%2Fwww.wfmynews2.com%2Farticle%2Fnews%2Fverify%2Fverify-why-does-am-radio-sound-worse-than-fm%2F83-489480515&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" 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.pbs.org/wgbh/aso/tryit/radio/radiorelayer.html">"A Science Odyssey: Radio Transmission: FM vs AM"</a>. <i>pbs.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">December 29,</span> 2022</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=pbs.org&rft.atitle=A+Science+Odyssey%3A+Radio+Transmission%3A+FM+vs+AM&rft_id=https%3A%2F%2Fwww.pbs.org%2Fwgbh%2Faso%2Ftryit%2Fradio%2Fradiorelayer.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-Nahin-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-Nahin_3-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNahin2001" class="citation book cs1">Nahin, Paul J. (2001). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=V1GBW6UD4CcC&pg=PR39"><i>The Science of Radio: With Matlab and Electronics Workbench Demonstration, 2nd Ed</i></a>. Springer Science & Business Media. pp. xxxix. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0387951504" title="Special:BookSources/0387951504"><bdi>0387951504</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Science+of+Radio%3A+With+Matlab+and+Electronics+Workbench+Demonstration%2C+2nd+Ed.&rft.pages=xxxix&rft.pub=Springer+Science+%26+Business+Media&rft.date=2001&rft.isbn=0387951504&rft.aulast=Nahin&rft.aufirst=Paul+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DV1GBW6UD4CcC%26pg%3DPR39&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" 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"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=njp.32101050973286&view=1up&seq=842">"Wireless Telegraphy"</a>, <i>The Electrician (London)</i>, October 14, 1898, pp. 814–815.</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"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=uc1.c2602954&view=1up&seq=476">"Hertzian Telegraphy at the Physical Society</a>, <i>The Electrician (London)</i>, January 28, 1898, pp. 452–453.</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"><a rel="nofollow" class="external text" href="https://gahistoricnewspapers.galileo.usg.edu/lccn/sn87090456/1902-03-08/ed-1/seq-6/">"Kentucky Inventor Solves Problem of Wireless Telephony"</a>, <i>The Sunny South</i>, March 8, 1902, p. 6.</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"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=WsYSAAAAYAAJ&pg=PA52">"The First Wireless Time Signal"</a> (letter from Captain J. L. Jayne), <i>Electrician and Mechanic</i>, January 1913, page 52. (Reprinted from <i>The American Jeweler</i>, October 1912, p. 411).</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"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=njp.32101042848000&view=1up&seq=903">"Vest-Pocket Wireless Receiving Instrument"</a>, <i>Electrical Review and Western Electrician</i>, April 11, 1914, p. 745.</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"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=-MI7AQAAMAAJ&pg=PA200">"Radio Apparatus"</a> (advertisement), <i>Radio Amateur News</i>, October 1919, p. 200.</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"><a rel="nofollow" class="external text" href="https://patentimages.storage.googleapis.com/pdfs/US706737.pdf">U.S. Patent 706,737</a>, submitted May 29, 1901, and issued August 12, 1902, to Reginald Fessenden.</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015057240221&view=1up&seq=111">"Experiments and Results in Wireless Telephony"</a>, by John Grant, <i>The American Telephone Journal</i>, January 26, 1907, pp. 49–51.</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"><i>The Continuous Wave</i> by Hugh G. J. Aitken, 1985, p. 61.</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">Aitken (1985), p. 62.</span> </li> <li id="cite_note-FESS-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-FESS_14-0">^</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://ewh.ieee.org/reg/7/millennium/radio/radio_wireless.html">"Fessenden, Reginald A. <i>Inventing the Wireless Telephone and the Future</i>"</a>. <a href="/wiki/IEEE" class="mw-redirect" title="IEEE">IEEE</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2017-07-22</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Fessenden%2C+Reginald+A.+Inventing+the+Wireless+Telephone+and+the+Future&rft.pub=IEEE&rft_id=https%3A%2F%2Fewh.ieee.org%2Freg%2F7%2Fmillennium%2Fradio%2Fradio_wireless.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text">Aitken (1985), p. 69.</span> </li> <li id="cite_note-experiments-16"><span class="mw-cite-backlink">^ <a href="#cite_ref-experiments_16-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-experiments_16-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">"Experiments and Results in Wireless Telephony" by John Grant, <i>The American Telephone Journal</i>. <a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015057240221;view=1up;seq=111">Part I</a>: January 26, 1907, pp. 49–51; <a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015057240221&view=1up&seq=147">Part II</a>: February 2, 1907, pp. 68–70, 79–80.</span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/columns-and-views/dec-21-1906-a-very-significant-date-in-radio/338869">"Dec. 21, 1906: A Very Significant Date in Radio"</a> by James E. O'Neal, December 22, 2016 (radioworld.com).</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"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015068171985&view=1up&seq=638">"Wireless Telephony: G. Possibilities"</a> by Reginald A. Fessenden, <i>Transactions of the American Institute of Electrical Engineers</i>, Vol. XXVII (1908), Part I, pp. 606–608.</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"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=789449A&KC=A&FT=D&ND=1&date=19050509&DB=&locale=en_EP#">"Method of Producing Alternating Currents With a High Number of Vibrations"</a> U.S. patent 789,449, filed June 10, 1903, and granted May 9, 1905, to Valdemar Poulsen.</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"><a rel="nofollow" class="external text" href="https://archive.org/stream/electricalexperi07gern#page/1000/mode/1up">"The Versatile Audion"</a> by H. Winfield Secor, <i>Electrical Experimenter</i>, February 1920, pages 1000–1001, 1080-1083.</span> </li> <li id="cite_note-McNicol13-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-McNicol13_21-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcNicol1946" class="citation web cs1">McNicol, Donald Monroe (August 11, 1946). <a rel="nofollow" class="external text" href="http://archive.org/details/radiosconquestof00mcnirich">"Radio's conquest of space"</a>. New York : Murry Hill – via Internet Archive.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Radio%27s+conquest+of+space&rft.pub=New+York+%3A+Murry+Hill&rft.date=1946-08-11&rft.aulast=McNicol&rft.aufirst=Donald+Monroe&rft_id=http%3A%2F%2Farchive.org%2Fdetails%2Fradiosconquestof00mcnirich&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text">"Pittsburgh's Contributions to Radio" by S. M. Kintner, <i>Proceedings of the Institute of Radio Engineers</i>, December 1932, pp. 1849–1862.</span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=uc1.b4540711&view=1up&seq=167"><i>Fessenden: Builder of Tomorrows</i></a> by Helen Fessenden, 1940, pp. 153–154.</span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/columns-and-views/fessenden-the-next-chapter/300426">"Fessenden — The Next Chapter"</a> by James E. O'Neal, <i>Radio World</i>, December 23, 2008 (radioworld.com).</span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/news-and-business/fessenden-worlds-first-broadcaster/311783">"Fessenden, World's First Broadcaster?"</a> by James E. O'Neal, <i>Radio World</i>, October 25, 2006 (radioworld.com).</span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><i>Father of Radio</i> by Lee de Forest, 1950, pages 225.</span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text">"I Was First to Sing Over the Radio" by Eugenia H. Farrar, <i>The American Swedish Monthly</i>, January 1955, pp. 10, 26.</span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://chroniclingamerica.loc.gov/lccn/sn82015415/1908-11-25/ed-1/seq-1/">"Mysterious Voices Startled Him: Wizard Isbell Thought He Heard Angels Talking"</a>, <i>Hawaiian Star</i>, November 25, 1908, p. 1.</span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text">Electro Importing Company catalog page, reproduced in <i>Charles Herrold, Inventor of Radio Broadcasting</i> by Gordon Greb and Mike Adams, 2003, p. 6.</span> </li> <li id="cite_note-cahiers-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-cahiers_30-0">^</a></b></span> <span class="reference-text"><i>"De la T.S.F. au Congo-Belge et de l'école pratique de Laeken aux concerts radiophoniques"</i> (Wireless in the Belgian Congo and from the Laeken Training School to Radio Concerts) by Bruno Brasseur, <i>Cahiers d'Histoire de la Radiodiffusion</i>, Number 118, October–December 2013.</span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.wpr.org/wprs-tradition-innovation">Wisconsin Public Radio's Tradition Of Innovation</a> (wpr.org)</span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=R88-AQAAMAAJ&pg=RA1-PA10">"A Newspaper's Use of the Radio Phone"</a>, <i>The Wireless Age</i>, November 1920, p. 10.</span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><i>The History of Broadcasting in the United Kingdom: Vol. I: The Birth of Broadcasting</i> by Asa Briggs, 1961, pp. 49–50.</span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</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.radionacional.com.ar/la-verdadera-historia-de-los-locos-de-la-azotea/">"La Verdadera Historia de los Locos de la Azotea – Radio Nacional"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=La+Verdadera+Historia+de+los+Locos+de+la+Azotea+%E2%80%93+Radio+Nacional&rft_id=https%3A%2F%2Fwww.radionacional.com.ar%2Fla-verdadera-historia-de-los-locos-de-la-azotea%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text"><i>The Broadcasters</i> by Red Barber, 1970, pp. 11–12.</span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=osu.32435066705633&view=1up&seq=200">"Miscellaneous: Amendments to Regulations"</a>, <i>Radio Service Bulletin</i>, January 3, 1922, p. 10.</span> </li> <li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text">"Radio Department: Broadcasting Stations", <i>Winnipeg Evening Tribune</i>, April 25, 1922, p. 5.</span> </li> <li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text"><a class="external text" href="https://commons.wikimedia.org/wiki/File:Will_Give_Concert_by_Wireless_Telephone_-_21JUL1912.jpg">"Will Give Concert by Wireless Telephone"</a>, <i>San Jose Mercury Herald</i>, July 21, 1912, page 27.</span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://chroniclingamerica.loc.gov/lccn/sn83045462/1914-03-29/ed-1/seq-2/">"Hear Tenor Through Wireless"</a>, <i>Washington Evening Star</i>, 29 March 1914, Part one, p. 2.</span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://eresources.nlb.gov.sg/newspapers/Digitised/Article/straitstimes19340425-1.2.100">"20th Anniversary of First Broadcast"</a> by Raymond Braillard, <i>The (Singapore) Straits Times</i>, 25 April 1934, p. 17 (reprinted from the British Broadcasting Corporation's <i>World-Radio</i>, 30 March 1934, p. 446) (nlb.gov.sg).</span> </li> <li id="cite_note-Telephony1916-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-Telephony1916_41-0">^</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://books.google.com/books?id=_NQ7AQAAMAAJ&pg=RA20-PT20">"Wireless Transmission of News"</a>. <i>Telephony</i>. <b>71</b> (27). Chicago: Telephony Publishing Co.: 32–33 December 30, 1916<span class="reference-accessdate">. Retrieved <span class="nowrap">December 23,</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=Telephony&rft.atitle=Wireless+Transmission+of+News&rft.volume=71&rft.issue=27&rft.pages=32-33&rft.date=1916-12-30&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D_NQ7AQAAMAAJ%26pg%3DRA20-PT20&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-Experimenter1917-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-Experimenter1917_42-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://archive.org/stream/electricalexperi04gern#page/650/mode/1up">"Election Returns Flashed by Radio to 7,000 Amateurs"</a>, <i>The Electrical Experimenter</i>, January 1917, page 650. (archive.org)</span> </li> <li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text">"Hear Caruso Sing by Wireless Thursday!", <i>Cleveland Plain Dealer</i>, April 17, 1919, page 1.</span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text">"Stop Wireless Concerts Here", <i>Cleveland Plain Dealer</i>, May 29, 1919, p. 9.</span> </li> <li id="cite_note-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.americanradiohistory.com/hd2/IDX-Site-Early-Radio/Archive-Wireless-World-IDX/80s/Wireless-World-1986-02-OCR-Page-0028.pdf">"Communications Commentary: PCGG"</a>, <i>Electronics & Wireless World</i>, February 1986, p. 26.</span> </li> <li id="cite_note-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-46">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=-MI7AQAAMAAJ&pg=PA295">"Foot Ball Score—Via Wireless Telephone"</a> by Morris Press, <i>Radio Amateur News</i>, December 1919, pp. 295, 321.</span> </li> <li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://news.google.com/newspapers?id=9P8tAAAAIBAJ&sjid=cYEFAAAAIBAJ&pg=1878%2C5556437">"Wireless Concert Given for Ottawa"</a>, <i>Montreal Gazette</i>, May 21, 1920, p. 4.</span> </li> <li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text">"Ninth California Theatre Concert", <i>Pacific Coast Musical Review</i>, May 29, 1920, page 9.</span> </li> <li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text">"Electrical Home Visitors to Hear Wireless Concert", <i>San Francisco Chronicle</i>, June 20, 1920, p. 8.</span> </li> <li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=hSEVAQAAMAAJ&pg=PA936">News by Radiotelephone"</a> (letter from Lee de Forest), <i>Electrical World</i>, April 23, 1921, p. 936.</span> </li> <li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><a class="external text" href="https://commons.wikimedia.org/wiki/File:The_News_Radiophone_to_Give_Vote_Results_-_31AUG1920.jpg">"The News Radiophone To Give Vote Results"</a>, <i>Detroit News</i>, August 31, 1920, pp. 1–2.</span> </li> <li id="cite_note-52"><span class="mw-cite-backlink"><b><a href="#cite_ref-52">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.americanradiohistory.com/hd2/IDX-Business/Magazines/Archive-BC-IDX/45-OCR/1945-08-20-BC-OCR-Page-0031.pdf">WWJ (advertisement)</a>, <i>Broadcasting Magazine</i>, August 20, 1945, p. 31. (americanradiohistory.com)</span> </li> <li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://news.google.com/newspapers?id=731RAAAAIBAJ&sjid=VWgDAAAAIBAJ&pg=1821%2C536271">"The Radio Amateur: Wireless Telephone Here"</a> by C. E. Urban, <i>Pittsburgh Gazette Times</i>, Sixth section, p. 13.</span> </li> <li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text"><a class="external text" href="https://commons.wikimedia.org/wiki/File:To_Give_Election_Results_by_Radio_-_28OCT1920.jpg">"To Give Election Results by Radio"</a>, <i>Cleveland Plain Dealer</i>, October 28, 1920, p. 10.</span> </li> <li id="cite_note-55"><span class="mw-cite-backlink"><b><a href="#cite_ref-55">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=njp.32101051572632&view=1up&seq=558">"KDKA"</a>, <i>The Wireless Age</i>, August 1922, p. 40.</span> </li> <li id="cite_note-56"><span class="mw-cite-backlink"><b><a href="#cite_ref-56">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external autonumber" href="https://www.wpr.org/wprs-tradition-innovation">[1]</a> WPR's Tradition Of Innovation</span> </li> <li id="cite_note-57"><span class="mw-cite-backlink"><b><a href="#cite_ref-57">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://news.google.com/newspapers?id=iI8tAAAAIBAJ&sjid=yZwFAAAAIBAJ&pg=5492%2C2424619">"Announcing the National Broadcasting Company, Inc."</a> (advertisement), <i>Reading (Pennsylvania) Eagle</i>, September 13, 1926, p. 10.</span> </li> <li id="cite_note-Hilmes-58"><span class="mw-cite-backlink"><b><a href="#cite_ref-Hilmes_58-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHilmes2011" class="citation book cs1">Hilmes, Michele (2011). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=qimGXa2MwHEC&pg=PA6"><i>Network Nations: A Transnational History of British and American Broadcasting</i></a>. Routledge. p. 6. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0415883856" title="Special:BookSources/978-0415883856"><bdi>978-0415883856</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Network+Nations%3A+A+Transnational+History+of+British+and+American+Broadcasting&rft.pages=6&rft.pub=Routledge&rft.date=2011&rft.isbn=978-0415883856&rft.aulast=Hilmes&rft.aufirst=Michele&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DqimGXa2MwHEC%26pg%3DPA6&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-59"><span class="mw-cite-backlink"><b><a href="#cite_ref-59">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=nyp.33433090816954&view=1up&seq=524">"Radio Fans to Pay Tribute to John Bull"</a>, <i>Popular Radio</i>, November 1922, p. 222.</span> </li> <li id="cite_note-Street2-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-Street2_60-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStreet2002" class="citation book cs1">Street, Sean (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=y7jo0IcUZeoC&pg=PA27"><i>A Concise History of British Radio, 1922-2002</i></a>. Kelly Publications. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781903053140" title="Special:BookSources/9781903053140"><bdi>9781903053140</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Concise+History+of+British+Radio%2C+1922-2002&rft.pub=Kelly+Publications&rft.date=2002&rft.isbn=9781903053140&rft.aulast=Street&rft.aufirst=Sean&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dy7jo0IcUZeoC%26pg%3DPA27&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-Street3-61"><span class="mw-cite-backlink">^ <a href="#cite_ref-Street3_61-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Street3_61-1"><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="CITEREFStreet2002" class="citation book cs1">Street, Sean (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=y7jo0IcUZeoC&pg=PA34"><i>A Concise History of British Radio, 1922-2002</i></a>. Kelly Publications. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781903053140" title="Special:BookSources/9781903053140"><bdi>9781903053140</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Concise+History+of+British+Radio%2C+1922-2002&rft.pub=Kelly+Publications&rft.date=2002&rft.isbn=9781903053140&rft.aulast=Street&rft.aufirst=Sean&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dy7jo0IcUZeoC%26pg%3DPA34&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-stereo-62"><span class="mw-cite-backlink">^ <a href="#cite_ref-stereo_62-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-stereo_62-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.fcc.gov/media/radio/am-stereo-broadcasting">"AM Stereo Broadcasting"</a> (fcc.gov)</span> </li> <li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.post-gazette.com/ae/tv-radio/2019/12/24/KQV-Pittsburgh-back-on-air-easy-listening-format/stories/201912240090">"Radio fans' holiday joy: KQV is back on the air"</a> by Maria Sciullo, <i>Pittsburgh Post-Gazette</i>, December 24, 2019.</span> </li> <li id="cite_note-64"><span class="mw-cite-backlink"><b><a href="#cite_ref-64">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://radioinsight.com/headlines/204891/1560-wfme-new-york-to-suspend-operations-friday/">"1560 WFME New York To Suspend Operations Friday"</a> by Lance Venta, February 11, 2021 (radioinsight.com).</span> </li> <li id="cite_note-65"><span class="mw-cite-backlink"><b><a href="#cite_ref-65">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/news-and-business/whatever-happened-to-shortwave-radio/302129">"Whatever Happened to Shortwave Radio?"</a> by James Careless, March 8, 2010 (radioworld.com).</span> </li> <li id="cite_note-66"><span class="mw-cite-backlink"><b><a href="#cite_ref-66">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLevenson2022" class="citation news cs1">Levenson, Michael (2022-12-10). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2022/12/10/business/media/am-radio-cars.html">"In a Future Filled With Electric Cars, AM Radio May Be Left Behind"</a>. <i>The New York Times</i>. <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/0362-4331">0362-4331</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2022-12-29</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=In+a+Future+Filled+With+Electric+Cars%2C+AM+Radio+May+Be+Left+Behind&rft.date=2022-12-10&rft.issn=0362-4331&rft.aulast=Levenson&rft.aufirst=Michael&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2022%2F12%2F10%2Fbusiness%2Fmedia%2Fam-radio-cars.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-67"><span class="mw-cite-backlink"><b><a href="#cite_ref-67">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGilboy2022" class="citation web cs1">Gilboy, James (2022-07-06). <a rel="nofollow" class="external text" href="https://www.thedrive.com/news/heres-why-some-automakers-tune-out-am-radios-in-new-cars">"Automakers Are Starting to Drop AM Radio in New Cars. Here's Why"</a>. <i>The Drive</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2022-12-29</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Drive&rft.atitle=Automakers+Are+Starting+to+Drop+AM+Radio+in+New+Cars.+Here%27s+Why&rft.date=2022-07-06&rft.aulast=Gilboy&rft.aufirst=James&rft_id=https%3A%2F%2Fwww.thedrive.com%2Fnews%2Fheres-why-some-automakers-tune-out-am-radios-in-new-cars&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-68"><span class="mw-cite-backlink"><b><a href="#cite_ref-68">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGitlin2023" class="citation news cs1">Gitlin, Jonathan M. (23 May 2023). <a rel="nofollow" class="external text" href="https://arstechnica.com/cars/2023/05/ev-advocates-join-tech-groups-and-automakers-to-oppose-am-radio-mandate/">"Congress wants AM radio in all new cars—trade groups say that's a mistake"</a>. <i>Ars Technica</i><span class="reference-accessdate">. Retrieved <span class="nowrap">23 May</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Ars+Technica&rft.atitle=Congress+wants+AM+radio+in+all+new+cars%E2%80%94trade+groups+say+that%27s+a+mistake&rft.date=2023-05-23&rft.aulast=Gitlin&rft.aufirst=Jonathan+M.&rft_id=https%3A%2F%2Farstechnica.com%2Fcars%2F2023%2F05%2Fev-advocates-join-tech-groups-and-automakers-to-oppose-am-radio-mandate%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-69"><span class="mw-cite-backlink"><b><a href="#cite_ref-69">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015035872822&view=1up&seq=478">"Statement of Major Edwin H. Armstrong"</a> (January 15, 1948), "Restrictive union practices of the American Federation of Musicians", <i>United States Congress, House Committee on Education and Labor</i> (1948 hearings), pages 144-145.</span> </li> <li id="cite_note-70"><span class="mw-cite-backlink"><b><a href="#cite_ref-70">^</a></b></span> <span class="reference-text">Scott Fybush. <a rel="nofollow" class="external text" href="https://www.fybush.com/nerw-20210217/">"Limbaugh Dead; What Next for Talk Radio?"</a> Fybush.com. February 17, 2021. Retrieved July 10, 2024.</span> </li> <li id="cite_note-71"><span class="mw-cite-backlink"><b><a href="#cite_ref-71">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.kintronic.com/wp-content/uploads/2016/01/NAB-AM-Receiver-Paper.pdf">"Smart AM Receivers for the 21st Century"</a> by Stephen F. Smith and Thomas F. King, <i>Proceedings of the National Association of Broadcasters Engineering Conference, Las Vegas, Nevada</i>, April 12, 2015, pages 1-2.</span> </li> <li id="cite_note-72"><span class="mw-cite-backlink"><b><a href="#cite_ref-72">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://handle.itu.int/11.1004/020.1000/4.118.43.en.100"><i>Final Acts of the Regional Radio Conference to Establish a Plan for the Broadcasting Service in the Band 1605-1705 in Region 2</i></a> (PDF) (Rio de Janeiro, 1988, ITU.int)</span> </li> <li id="cite_note-73"><span class="mw-cite-backlink"><b><a href="#cite_ref-73">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.worldradiohistory.com/Archive-BC/BC-1988/BC-1988-05-23.pdf#page=55">"RIO is stage for AM spectrum conference"</a>, <i>Broadcasting</i>, May 23, 1988, pp. 55–56.</span> </li> <li id="cite_note-74"><span class="mw-cite-backlink"><b><a href="#cite_ref-74">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.worldradiohistory.com/Archive-Billboard/90s/1990/BB-1990-04-28.pdf#page=10">"FCC Votes To Proceed With AM-Band Improvement Plans"</a> by Bill Holland, <i>Billboard</i>, April 28, 1990, page 10.</span> </li> <li id="cite_note-75"><span class="mw-cite-backlink"><b><a href="#cite_ref-75">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/news-and-business/life-on-expanded-band-is-pretty-good">"Life on Expanded Band Is (Pretty) Good"</a> by Randy J. Stine, February 28, 2006 (radioworld.com)</span> </li> <li id="cite_note-76"><span class="mw-cite-backlink"><b><a href="#cite_ref-76">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=uva.x004848309;view=1up;seq=268">"Mass Media Bureau Announces Revised AM Expanded Band Allotment Plan and Filing Window for Eligible Stations"</a> (FCC DA 97-537), March 17, 1997.</span> </li> <li id="cite_note-77"><span class="mw-cite-backlink"><b><a href="#cite_ref-77">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMorgan2002" class="citation news cs1">Morgan, TaNoah (11 October 2002). <a rel="nofollow" class="external text" href="https://www.baltimoresun.com/news/bs-xpm-2002-10-11-0210110010-story.html">"Digital radio approved by FCC"</a>. <i><a href="/wiki/Baltimore_Sun" class="mw-redirect" title="Baltimore Sun">Baltimore Sun</a></i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Baltimore+Sun&rft.atitle=Digital+radio+approved+by+FCC&rft.date=2002-10-11&rft.aulast=Morgan&rft.aufirst=TaNoah&rft_id=https%3A%2F%2Fwww.baltimoresun.com%2Fnews%2Fbs-xpm-2002-10-11-0210110010-story.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-78"><span class="mw-cite-backlink"><b><a href="#cite_ref-78">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGutmann2007" class="citation news cs1">Gutmann, Peter (23 August 2007). <a rel="nofollow" class="external text" href="https://www.rbr.com/hd-radio-rules-take-effect-by-peter-gutmann/">"HD Radio rules take effect"</a>. <i>Radio+Television Business Report (RBR.com)</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Radio%2BTelevision+Business+Report+%28RBR.com%29&rft.atitle=HD+Radio+rules+take+effect&rft.date=2007-08-23&rft.aulast=Gutmann&rft.aufirst=Peter&rft_id=https%3A%2F%2Fwww.rbr.com%2Fhd-radio-rules-take-effect-by-peter-gutmann%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-79"><span class="mw-cite-backlink"><b><a href="#cite_ref-79">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.federalregister.gov/documents/2020/01/07/2019-27609/all-digital-am-broadcasting-revitalization-of-the-am-radio-service">"Proposed rule: All-digital AM broadcasting, revitalization of the AM radio service"</a>. <i><a href="/wiki/The_Federal_Register" class="mw-redirect" title="The Federal Register">The Federal Register</a></i>. 25 November 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Federal+Register&rft.atitle=Proposed+rule%3A+All-digital+AM+broadcasting%2C+revitalization+of+the+AM+radio+service&rft.date=2019-11-25&rft_id=https%3A%2F%2Fwww.federalregister.gov%2Fdocuments%2F2020%2F01%2F07%2F2019-27609%2Fall-digital-am-broadcasting-revitalization-of-the-am-radio-service&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-80"><span class="mw-cite-backlink"><b><a href="#cite_ref-80">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.federalregister.gov/documents/2020/12/03/2020-25252/all-digital-am-broadcasting-revitalization-of-the-am-radio-service">"Final rule: All-digital AM broadcasting, revitalization of the AM radio service"</a>. <i><a href="/wiki/The_Federal_Register" class="mw-redirect" title="The Federal Register">The Federal Register</a></i>. 3 December 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Federal+Register&rft.atitle=Final+rule%3A+All-digital+AM+broadcasting%2C+revitalization+of+the+AM+radio+service&rft.date=2020-12-03&rft_id=https%3A%2F%2Fwww.federalregister.gov%2Fdocuments%2F2020%2F12%2F03%2F2020-25252%2Fall-digital-am-broadcasting-revitalization-of-the-am-radio-service&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-81"><span class="mw-cite-backlink"><b><a href="#cite_ref-81">^</a></b></span> <span class="reference-text">Logo for <a href="/wiki/WCHL_(AM)" title="WCHL (AM)">WCHL</a>, 1360 AM in Chapel Hill, North Carolina, whose publicized signal is over FM translator W250BP at 97.9 MHz.</span> </li> <li id="cite_note-FCC_auth-82"><span class="mw-cite-backlink">^ <a href="#cite_ref-FCC_auth_82-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-FCC_auth_82-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=osu.32435081039638&view=1up&seq=874">"Report and Order: In the Matter of Amendment of Service and Eligibility Rules for FM Broadcast Translator Stations"</a> (MB Docket Mo. 07-172, RM-11338), June 29, 2009, pages 9642–9660.</span> </li> <li id="cite_note-OK-83"><span class="mw-cite-backlink">^ <a href="#cite_ref-OK_83-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-OK_83-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.commlawblog.com/2009/06/articles/broadcast/fcc-oks-am-on-fm-translators/">"FCC OK's AM on FM Translators"</a> by FHH Law, June 30, 2009 (commlawblog.com).</span> </li> <li id="cite_note-84"><span class="mw-cite-backlink"><b><a href="#cite_ref-84">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/news-and-business/uses-of-fm-translators-morph-quickly">"Uses of FM Translators Morph Quickly"</a> by Randy J. Stine, August 3, 2011 (radioworld.com)</span> </li> <li id="cite_note-worry-85"><span class="mw-cite-backlink">^ <a href="#cite_ref-worry_85-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-worry_85-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.radioworld.com/news-and-business/headlines/special-report-am-advocates-watch-and-worry">"Special Report: AM Advocates Watch and Worry"</a> by Randy J. Stine, October 5, 2020 (radioworld.com)</span> </li> <li id="cite_note-86"><span class="mw-cite-backlink"><b><a href="#cite_ref-86">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.federalregister.gov/documents/2018/11/20/2018-25101/revitalization-of-the-am-radio-service">"Proposed Rule: Revitalization of the AM Radio Service"</a>, <i>Federal Register</i>, November 20, 2018.</span> </li> <li id="cite_note-87"><span class="mw-cite-backlink"><b><a href="#cite_ref-87">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMuller2023" class="citation web cs1">Muller, Joann (17 May 2023). <a rel="nofollow" class="external text" href="https://www.axios.com/2023/05/17/am-radio-congress-cars">"Scoop: Congress moves to preserve AM radio in cars"</a>. Axios<span class="reference-accessdate">. Retrieved <span class="nowrap">18 May</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Scoop%3A+Congress+moves+to+preserve+AM+radio+in+cars&rft.pub=Axios&rft.date=2023-05-17&rft.aulast=Muller&rft.aufirst=Joann&rft_id=https%3A%2F%2Fwww.axios.com%2F2023%2F05%2F17%2Fam-radio-congress-cars&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-88"><span class="mw-cite-backlink"><b><a href="#cite_ref-88">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation report cs1">Federal Communications Commission rules (Report). 47 CFR §2.106.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=Federal+Communications+Commission+rules&rft.pages=47+CFR+%C2%A72.106&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-89"><span class="mw-cite-backlink"><b><a href="#cite_ref-89">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.theradiohistorian.org/Apex/Apex1.htm">"America's Apex Broadcasting Stations of the 1930s"</a> by John Schneider, <i>Monitoring Times Magazine</i>, December 2010. (theradiohistorian.com)</span> </li> <li id="cite_note-90"><span class="mw-cite-backlink"><b><a href="#cite_ref-90">^</a></b></span> <span class="reference-text"><i>The Gas Pipe Networks</i> by Louis M. Bloch, Jr, 1980.</span> </li> <li id="cite_note-91"><span class="mw-cite-backlink"><b><a href="#cite_ref-91">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.biennophone.ch/telefonrundspruch.htm">"Sammlung alter Biennophone-Radios"</a>. Biennophone.ch<span class="reference-accessdate">. Retrieved <span class="nowrap">23 July</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=Sammlung+alter+Biennophone-Radios&rft.pub=Biennophone.ch&rft_id=http%3A%2F%2Fwww.biennophone.ch%2Ftelefonrundspruch.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> <li id="cite_note-92"><span class="mw-cite-backlink"><b><a href="#cite_ref-92">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.fcc.gov/media/radio/digital-radio">"Digital Radio"</a> (fcc.gov)</span> </li> <li id="cite_note-93"><span class="mw-cite-backlink"><b><a href="#cite_ref-93">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDavid_J._HessProfessor_David_J_HessRobert_Gottlieb2009" class="citation book cs1">David J. Hess; Professor David J Hess; Robert Gottlieb (2009). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=BS7rsOQv5MUC"><i>Localist Movements in a Global Economy Sustainability, Justice, and Urban Development in the United StatesStates</i></a>. MIT Press. p. 199. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780262012645" title="Special:BookSources/9780262012645"><bdi>9780262012645</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">7 February</span> 2021</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Localist+Movements+in+a+Global+Economy+Sustainability%2C+Justice%2C+and+Urban+Development+in+the+United+StatesStates&rft.pages=199&rft.pub=MIT+Press&rft.date=2009&rft.isbn=9780262012645&rft.au=David+J.+Hess&rft.au=Professor+David+J+Hess&rft.au=Robert+Gottlieb&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DBS7rsOQv5MUC&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAM+broadcasting" class="Z3988"></span></span> </li> </ol></div></div> <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 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href="/wiki/Template:Audio_broadcasting" title="Template:Audio broadcasting"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Audio_broadcasting" title="Template talk:Audio broadcasting"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Audio_broadcasting" title="Special:EditPage/Template:Audio broadcasting"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Analog_and_digital_audio_broadcasting" style="font-size:114%;margin:0 4em"><a href="/wiki/Analog_recording" title="Analog recording">Analog</a> and <a href="/wiki/Digital_audio" title="Digital audio">digital audio</a> <a href="/wiki/Broadcasting" title="Broadcasting">broadcasting</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Terrestrial</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Radio" title="Radio">Radio</a> <a href="/wiki/Modulation" title="Modulation">modulation</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Amplitude_modulation" title="Amplitude modulation">AM</a></li> <li><a href="/wiki/Frequency_modulation" title="Frequency modulation">FM</a></li> <li><a href="/wiki/Orthogonal_frequency-division_multiplexing" title="Orthogonal frequency-division multiplexing">COFDM</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Frequency_allocation" title="Frequency allocation">Frequency allocations</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Longwave" title="Longwave">LW</a> (<a href="/wiki/Low_frequency" title="Low frequency">LF</a>)</li> <li><a href="/wiki/Medium_wave" title="Medium wave">MW</a> (<a href="/wiki/Medium_frequency" title="Medium frequency">MF</a>)</li> <li><a href="/wiki/Shortwave_radio" title="Shortwave radio">SW</a> (<a href="/wiki/High_frequency" title="High frequency">HF</a>)</li> <li><a href="/wiki/Very_high_frequency" title="Very high frequency">VHF</a> (<a href="/wiki/Band_I" title="Band I">low</a> / <a href="/wiki/Band_II" title="Band II">mid</a> / <a href="/wiki/Band_III" title="Band III">high</a>)</li> <li><a href="/wiki/L_band" title="L band">L band</a> (<a href="/wiki/Ultra_high_frequency" title="Ultra high frequency">UHF</a>)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Digital systems</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CAM-D" title="CAM-D">CAM-D</a></li> <li><a href="/wiki/Digital_Audio_Broadcasting" title="Digital Audio Broadcasting">DAB/DAB+</a></li> <li><a href="/wiki/Digital_Radio_Mondiale" title="Digital Radio Mondiale">DRM/DRM+</a></li> <li><a href="/wiki/ISDB-T#ISDB-Tsb" class="mw-redirect" title="ISDB-T">ISDB-Tsb</a></li> <li><a href="/wiki/FMeXtra" title="FMeXtra">FMeXtra</a></li> <li><a href="/wiki/HD_Radio" title="HD Radio">HD Radio</a></li> <li>CDR</li> <li><a href="/wiki/DVB-T2" title="DVB-T2">DVB-T2 Lite</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Satellite</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Frequency allocations</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/C_band_(IEEE)" title="C band (IEEE)">C band</a></li> <li><a href="/wiki/Ku_band" title="Ku band">K<sub>u</sub> band</a></li> <li><a href="/wiki/L_band" title="L band">L band</a></li> <li><a href="/wiki/S_band" title="S band">S band</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Digital systems</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Astra_Digital_Radio" title="Astra Digital Radio">ADR</a></li> <li><a href="/wiki/Digital_audio_broadcasting" class="mw-redirect" title="Digital audio broadcasting">DAB-S</a></li> <li><a href="/wiki/DVB-SH" title="DVB-SH">DVB-SH</a></li> <li><a href="/wiki/S-DMB" title="S-DMB">S-DMB</a></li> <li><a href="/wiki/ETSI_Satellite_Digital_Radio" title="ETSI Satellite Digital Radio">SDR</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Commercial_broadcasting" title="Commercial broadcasting">Commercial radio</a> providers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Sirius_XM" title="Sirius XM">Sirius XM</a> <ul><li><a href="/wiki/Sirius_XM_Canada" title="Sirius XM Canada">Canada</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Audio_codec" title="Audio codec">Codecs</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">AAC</a></li> <li><a href="/wiki/Extended_Adaptive_Multi-Rate_%E2%80%93_Wideband" title="Extended Adaptive Multi-Rate – Wideband">AMR-WB+</a></li> <li><a href="/wiki/High-Definition_Coding" title="High-Definition Coding">HDC</a></li> <li><a href="/wiki/High-Efficiency_Advanced_Audio_Coding" title="High-Efficiency Advanced Audio Coding">HE-AAC</a></li> <li><a href="/wiki/MPEG-1_Audio_Layer_II" title="MPEG-1 Audio Layer II">MPEG-1 Audio Layer II</a></li> <li><a href="/wiki/Dynamic_Resolution_Adaptation" title="Dynamic Resolution Adaptation">DRA+</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Subcarrier" title="Subcarrier">Subcarrier</a> signals</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Amplitude_modulation_signalling_system" title="Amplitude modulation signalling system">AMSS</a></li> <li><a href="/wiki/DirectBand" title="DirectBand">DirectBand</a></li> <li><a href="/wiki/Program-associated_data" title="Program-associated data">PAD</a></li> <li><a href="/wiki/Radio_Data_System" title="Radio Data System">RDS/RBDS</a></li> <li><a href="/wiki/Subsidiary_communications_authority" title="Subsidiary communications authority">SCA/SCMO</a></li> <li><a href="/wiki/Data_Radio_Channel" title="Data Radio Channel">DARC</a></li></ul> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Related_topics" style="font-size:114%;margin:0 4em">Related topics</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technical (audio)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Audio_data_compression" class="mw-redirect" title="Audio data compression">Audio data compression</a></li> <li><a href="/wiki/Audio_signal_processing" title="Audio signal processing">Audio signal processing</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technical (<a href="/wiki/AM_stereo" title="AM stereo">AM stereo</a> formats)</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/AM_stereo#Belar_System" title="AM stereo">Belar</a></li> <li><a href="/wiki/C-QUAM" title="C-QUAM">C-QUAM</a></li> <li><a href="/wiki/AM_stereo#Harris_System" title="AM stereo">Harris</a></li> <li><a href="/wiki/AM_stereo#Kahn-Hazeltine" title="AM stereo">Kahn-Hazeltine</a></li> <li><a href="/wiki/AM_stereo#Magnavox_System" title="AM stereo">Magnavox</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technical (emission)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a class="mw-selflink selflink">AM broadcasting</a></li> <li><a href="/wiki/AM_expanded_band" title="AM expanded band">AM expanded band</a></li> <li><a href="/wiki/Cable_radio" title="Cable radio">Cable radio</a></li> <li><a href="/wiki/Digital_radio" title="Digital radio">Digital radio</a></li> <li><a href="/wiki/Error_detection_and_correction" title="Error detection and correction">Error detection and correction</a></li> <li><a href="/wiki/FM_broadcast_band" title="FM broadcast band">FM broadcast band</a></li> <li><a href="/wiki/FM_broadcasting" title="FM broadcasting">FM broadcasting</a></li> <li><a href="/wiki/FM_extended_band_in_Brazil" title="FM extended band in Brazil">FM extended band in Brazil</a></li> <li><a href="/wiki/Multipath_propagation" title="Multipath propagation">Multipath propagation</a></li> <li><a href="/wiki/Shortwave_relay_station" title="Shortwave relay station">Shortwave relay station</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Cultural</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_radio" title="History of radio">History of radio</a></li> <li><a href="/wiki/International_broadcasting" title="International broadcasting">International broadcasting</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><b><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/1/1d/Radio_icon.png" decoding="async" width="32" height="23" class="mw-file-element" data-file-width="30" data-file-height="22" /></span></span> </span><a href="/wiki/Portal:Radio" title="Portal:Radio">Radio portal</a></b></li> <li><a href="/wiki/Comparison_of_radio_systems" title="Comparison of radio systems">Comparison of radio systems</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Telecommunications" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed 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:Telecommunications" title="Template:Telecommunications"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Telecommunications" title="Template talk:Telecommunications"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Telecommunications" title="Special:EditPage/Template:Telecommunications"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Telecommunications" style="font-size:114%;margin:0 4em"><a href="/wiki/Telecommunications" title="Telecommunications">Telecommunications</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/History_of_telecommunication" title="History of telecommunication">History</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beacon#For_defensive_communications" title="Beacon">Beacon</a></li> <li><a href="/wiki/History_of_broadcasting" title="History of broadcasting">Broadcasting</a></li> <li><a href="/wiki/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Cable_television" title="Cable television">Cable TV</a></li> <li><a href="/wiki/Communications_satellite#History" title="Communications satellite">Communications satellite</a></li> <li><a href="/wiki/Computer_network#History" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_compression" title="Data compression">Data compression</a> <ul><li><a href="/wiki/Audio_coding_format" title="Audio coding format">audio</a></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Image_compression" title="Image compression">image</a></li> <li><a href="/wiki/Video_coding_format" title="Video coding format">video</a></li></ul></li> <li><a href="/wiki/Digital_media" title="Digital media">Digital media</a> <ul><li><a href="/wiki/Internet_video" title="Internet video">Internet video</a></li> <li><a href="/wiki/Online_video_platform" title="Online video platform">online video platform</a></li> <li><a href="/wiki/Social_media" title="Social media">social media</a></li> <li><a href="/wiki/Streaming_media" title="Streaming media">streaming</a></li></ul></li> <li><a href="/wiki/Drums_in_communication" title="Drums in communication">Drums</a></li> <li><a href="/wiki/Edholm%27s_law" title="Edholm's law">Edholm's law</a></li> <li><a href="/wiki/Electrical_telegraph#History" title="Electrical telegraph">Electrical telegraph</a></li> <li><a href="/wiki/Fax#History" title="Fax">Fax</a></li> <li><a href="/wiki/Heliograph#History" title="Heliograph">Heliographs</a></li> <li><a href="/wiki/Hydraulic_telegraph#Greek_hydraulic_semaphore_system" title="Hydraulic telegraph">Hydraulic telegraph</a></li> <li><a href="/wiki/Information_Age" title="Information Age">Information Age</a></li> <li><a href="/wiki/Information_revolution" class="mw-redirect" title="Information revolution">Information revolution</a></li> <li><a href="/wiki/History_of_the_Internet" title="History of the Internet">Internet</a></li> <li><a href="/wiki/Mass_media#History" title="Mass media">Mass media</a></li> <li><a href="/wiki/History_of_mobile_phones" title="History of mobile phones">Mobile phone</a> <ul><li><a href="/wiki/Smartphone" title="Smartphone">Smartphone</a></li></ul></li> <li><a href="/wiki/Optical_communication" title="Optical communication">Optical telecommunication</a></li> <li><a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraphy</a></li> <li><a href="/wiki/Pager" title="Pager">Pager</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li> <li><a href="/wiki/History_of_prepaid_mobile_phones" title="History of prepaid mobile phones">Prepaid mobile phone</a></li> <li><a href="/wiki/History_of_radio" title="History of radio">Radio</a></li> <li><a href="/wiki/Radiotelephone" title="Radiotelephone">Radiotelephone</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Satellite communications</a></li> <li><a href="/wiki/Semaphore" title="Semaphore">Semaphore</a> <ul><li><a href="/wiki/Phryctoria" title="Phryctoria">Phryctoria</a></li></ul></li> <li><a href="/wiki/Semiconductor" title="Semiconductor">Semiconductor</a> <ul><li><a href="/wiki/Semiconductor_device" title="Semiconductor device">device</a></li> <li><a href="/wiki/MOSFET" title="MOSFET">MOSFET</a></li> <li><a href="/wiki/History_of_the_transistor" title="History of the transistor">transistor</a></li></ul></li> <li><a href="/wiki/Smoke_signal" title="Smoke signal">Smoke signals</a></li> <li><a href="/wiki/History_of_telecommunication" title="History of telecommunication">Telecommunications history</a></li> <li><a href="/wiki/Telautograph" title="Telautograph">Telautograph</a></li> <li><a href="/wiki/Telegraphy" title="Telegraphy">Telegraphy</a></li> <li><a href="/wiki/Teleprinter" title="Teleprinter">Teleprinter</a> (teletype)</li> <li><a href="/wiki/History_of_the_telephone" title="History of the telephone">Telephone</a></li> <li><i><a href="/wiki/The_Telephone_Cases" title="The Telephone Cases">The Telephone Cases</a></i></li> <li><a href="/wiki/History_of_television" title="History of television">Television</a> <ul><li><a href="/wiki/Digital_television" title="Digital television">digital</a></li> <li><a href="/wiki/Streaming_television" title="Streaming television">streaming</a></li></ul></li> <li><a href="/wiki/Submarine_communications_cable#Early_history:_telegraph_and_coaxial_cables" title="Submarine communications cable">Undersea telegraph line</a></li> <li><a href="/wiki/History_of_videotelephony" title="History of videotelephony">Videotelephony</a></li> <li><a href="/wiki/Whistled_language" title="Whistled language">Whistled language</a></li> <li><a href="/wiki/Wireless_revolution" class="mw-redirect" title="Wireless revolution">Wireless revolution</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pioneers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nasir_Ahmed_(engineer)" title="Nasir Ahmed (engineer)">Nasir Ahmed</a></li> <li><a href="/wiki/Edwin_Howard_Armstrong" title="Edwin Howard Armstrong">Edwin Howard Armstrong</a></li> <li><a href="/wiki/Mohamed_M._Atalla" title="Mohamed M. Atalla">Mohamed M. Atalla</a></li> <li><a href="/wiki/John_Logie_Baird" title="John Logie Baird">John Logie Baird</a></li> <li><a href="/wiki/Paul_Baran" title="Paul Baran">Paul Baran</a></li> <li><a href="/wiki/John_Bardeen" title="John Bardeen">John Bardeen</a></li> <li><a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a></li> <li><a href="/wiki/Emile_Berliner" title="Emile Berliner">Emile Berliner</a></li> <li><a href="/wiki/Tim_Berners-Lee" title="Tim Berners-Lee">Tim Berners-Lee</a></li> <li><a href="/wiki/Francis_Blake_(inventor)" title="Francis Blake (inventor)">Francis Blake</a></li> <li><a href="/wiki/Jagadish_Chandra_Bose" title="Jagadish Chandra Bose">Jagadish Chandra Bose</a></li> <li><a href="/wiki/Charles_Bourseul" title="Charles Bourseul">Charles Bourseul</a></li> <li><a href="/wiki/Walter_Houser_Brattain" title="Walter Houser Brattain">Walter Houser Brattain</a></li> <li><a href="/wiki/Vint_Cerf" title="Vint Cerf">Vint Cerf</a></li> <li><a href="/wiki/Claude_Chappe" title="Claude Chappe">Claude Chappe</a></li> <li><a href="/wiki/Yogen_Dalal" class="mw-redirect" title="Yogen Dalal">Yogen Dalal</a></li> <li><a href="/wiki/Daniel_Davis_Jr." title="Daniel Davis Jr.">Daniel Davis Jr.</a></li> <li><a href="/wiki/Donald_Davies" title="Donald Davies">Donald Davies</a></li> <li><a href="/wiki/Amos_Dolbear" title="Amos Dolbear">Amos Dolbear</a></li> <li><a href="/wiki/Thomas_Edison" title="Thomas Edison">Thomas Edison</a></li> <li><a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a></li> <li><a href="/wiki/Philo_Farnsworth" title="Philo Farnsworth">Philo Farnsworth</a></li> <li><a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a></li> <li><a href="/wiki/Elisha_Gray" title="Elisha Gray">Elisha Gray</a></li> <li><a href="/wiki/Oliver_Heaviside" title="Oliver Heaviside">Oliver Heaviside</a></li> <li><a href="/wiki/Robert_Hooke" title="Robert Hooke">Robert Hooke</a></li> <li><a href="/wiki/Erna_Schneider_Hoover" title="Erna Schneider Hoover">Erna Schneider Hoover</a></li> <li><a href="/wiki/Harold_Hopkins_(physicist)" title="Harold Hopkins (physicist)">Harold Hopkins</a></li> <li><a href="/wiki/Gardiner_Greene_Hubbard" title="Gardiner Greene Hubbard">Gardiner Greene Hubbard</a></li> <li><a href="/wiki/List_of_Internet_pioneers" title="List of Internet pioneers">Internet pioneers</a></li> <li><a href="/wiki/Bob_Kahn" class="mw-redirect" title="Bob Kahn">Bob Kahn</a></li> <li><a href="/wiki/Dawon_Kahng" title="Dawon Kahng">Dawon Kahng</a></li> <li><a href="/wiki/Charles_K._Kao" title="Charles K. Kao">Charles K. Kao</a></li> <li><a href="/wiki/Narinder_Singh_Kapany" title="Narinder Singh Kapany">Narinder Singh Kapany</a></li> <li><a href="/wiki/Hedy_Lamarr" title="Hedy Lamarr">Hedy Lamarr</a></li> <li><a href="/wiki/Roberto_Landell_de_Moura" title="Roberto Landell de Moura">Roberto Landell de Moura</a></li> <li><a href="/wiki/Innocenzo_Manzetti" title="Innocenzo Manzetti">Innocenzo Manzetti</a></li> <li><a href="/wiki/Guglielmo_Marconi" title="Guglielmo Marconi">Guglielmo Marconi</a></li> <li><a href="/wiki/Robert_Metcalfe" title="Robert Metcalfe">Robert Metcalfe</a></li> <li><a href="/wiki/Antonio_Meucci" title="Antonio Meucci">Antonio Meucci</a></li> <li><a href="/wiki/Samuel_Morse" title="Samuel Morse">Samuel Morse</a></li> <li><a href="/wiki/Jun-ichi_Nishizawa" title="Jun-ichi Nishizawa">Jun-ichi Nishizawa</a></li> <li><a href="/wiki/Charles_Grafton_Page" title="Charles Grafton Page">Charles Grafton Page</a></li> <li><a href="/wiki/Radia_Perlman" title="Radia Perlman">Radia Perlman</a></li> <li><a href="/wiki/Alexander_Stepanovich_Popov" class="mw-redirect" title="Alexander Stepanovich Popov">Alexander Stepanovich Popov</a></li> <li><a href="/wiki/Tivadar_Pusk%C3%A1s" title="Tivadar Puskás">Tivadar Puskás</a></li> <li><a href="/wiki/Johann_Philipp_Reis" title="Johann Philipp Reis">Johann Philipp Reis</a></li> <li><a href="/wiki/Claude_Shannon" title="Claude Shannon">Claude Shannon</a></li> <li><a href="/wiki/Almon_Brown_Strowger" title="Almon Brown Strowger">Almon Brown Strowger</a></li> <li><a href="/wiki/Henry_Sutton_(inventor)" title="Henry Sutton (inventor)">Henry Sutton</a></li> <li><a href="/wiki/Charles_Sumner_Tainter" title="Charles Sumner Tainter">Charles Sumner Tainter</a></li> <li><a href="/wiki/Nikola_Tesla" title="Nikola Tesla">Nikola Tesla</a></li> <li><a href="/wiki/Camille_Tissot" title="Camille Tissot">Camille Tissot</a></li> <li><a href="/wiki/Alfred_Vail" title="Alfred Vail">Alfred Vail</a></li> <li><a href="/wiki/Thomas_A._Watson" title="Thomas A. Watson">Thomas A. Watson</a></li> <li><a href="/wiki/Charles_Wheatstone" title="Charles Wheatstone">Charles Wheatstone</a></li> <li><a href="/wiki/Vladimir_K._Zworykin" title="Vladimir K. Zworykin">Vladimir K. Zworykin</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transmission_medium" title="Transmission medium">Transmission<br />media</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coaxial_cable" title="Coaxial cable">Coaxial cable</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a> <ul><li><a href="/wiki/Optical_fiber" title="Optical fiber">optical fiber</a></li></ul></li> <li><a href="/wiki/Free-space_optical_communication" title="Free-space optical communication">Free-space optical communication</a></li> <li><a href="/wiki/Molecular_communication" title="Molecular communication">Molecular communication</a></li> <li><a href="/wiki/Radio_wave" title="Radio wave">Radio waves</a> <ul><li><a href="/wiki/Wireless" title="Wireless">wireless</a></li></ul></li> <li><a href="/wiki/Transmission_line" title="Transmission line">Transmission line</a> <ul><li><a href="/wiki/Telecommunication_circuit" title="Telecommunication circuit">telecommunication circuit</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Network_topology" title="Network topology">Network topology</a><br />and switching</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">Bandwidth</a></li> <li><a href="/wiki/Telecommunications_link" title="Telecommunications link">Links</a></li> <li><a href="/wiki/Node_(networking)" title="Node (networking)">Nodes</a> <ul><li><a href="/wiki/Terminal_(telecommunication)" title="Terminal (telecommunication)">terminal</a></li></ul></li> <li><a href="/wiki/Network_switch" title="Network switch">Network switching</a> <ul><li><a href="/wiki/Circuit_switching" title="Circuit switching">circuit</a></li> <li><a href="/wiki/Packet_switching" title="Packet switching">packet</a></li></ul></li> <li><a href="/wiki/Telephone_exchange" title="Telephone exchange">Telephone exchange</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Multiplexing" title="Multiplexing">Multiplexing</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">Space-division</a></li> <li><a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">Frequency-division</a></li> <li><a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">Time-division</a></li> <li><a href="/wiki/Polarization-division_multiplexing" title="Polarization-division multiplexing">Polarization-division</a></li> <li><a href="/wiki/Orbital_angular_momentum_multiplexing" title="Orbital angular momentum multiplexing">Orbital angular-momentum</a></li> <li><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">Code-division</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Communication_protocol" title="Communication protocol">Communication protocol</a></li> <li><a href="/wiki/Computer_network" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_communication" title="Data communication">Data transmission</a></li> <li><a href="/wiki/Store_and_forward" title="Store and forward">Store and forward</a></li> <li><a href="/wiki/Telecommunications_equipment" title="Telecommunications equipment">Telecommunications equipment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Types of network</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_network" title="Cellular network">Cellular network</a></li> <li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Local_area_network" title="Local area network">LAN</a></li> <li><a href="/wiki/Mobile_telephony" title="Mobile telephony">Mobile</a></li> <li><a href="/wiki/Next-generation_network" title="Next-generation network">NGN</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">Public Switched Telephone</a></li> <li><a href="/wiki/Radio_network" title="Radio network">Radio</a></li> <li><a href="/wiki/Television_broadcasting" class="mw-redirect" title="Television broadcasting">Television</a></li> <li><a href="/wiki/Telex" title="Telex">Telex</a></li> <li><a href="/wiki/UUCP" title="UUCP">UUCP</a></li> <li><a href="/wiki/Wide_area_network" title="Wide area network">WAN</a></li> <li><a href="/wiki/Wireless_network" title="Wireless network">Wireless network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Notable networks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARPANET" title="ARPANET">ARPANET</a></li> <li><a href="/wiki/BITNET" title="BITNET">BITNET</a></li> <li><a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a></li> <li><a href="/wiki/FidoNet" title="FidoNet">FidoNet</a></li> <li><a href="/wiki/Internet" title="Internet">Internet</a></li> <li><a href="/wiki/Internet2" title="Internet2">Internet2</a></li> <li><a href="/wiki/JANET" title="JANET">JANET</a></li> <li><a href="/wiki/NPL_network" title="NPL network">NPL network</a></li> <li><a href="/wiki/Toasternet" title="Toasternet">Toasternet</a></li> <li><a href="/wiki/Usenet" title="Usenet">Usenet</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Locations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Category:Telecommunications_in_Africa" title="Category:Telecommunications in Africa">Africa</a></li> <li>Americas <ul><li><a href="/wiki/Category:Telecommunications_in_North_America" title="Category:Telecommunications in North America">North</a></li> <li><a href="/wiki/Category:Telecommunications_in_South_America" title="Category:Telecommunications in South America">South</a></li></ul></li> <li><a href="/wiki/Category:Communications_in_Antarctica" title="Category:Communications in Antarctica">Antarctica</a></li> <li><a href="/wiki/Category:Telecommunications_in_Asia" title="Category:Telecommunications in Asia">Asia</a></li> <li><a href="/wiki/Category:Telecommunications_in_Europe" title="Category:Telecommunications in Europe">Europe</a></li> <li><a href="/wiki/Category:Telecommunications_in_Oceania" title="Category:Telecommunications in Oceania">Oceania</a></li> <li>(<a href="/wiki/List_of_telecommunications_regulatory_bodies" title="List of telecommunications regulatory bodies">Global telecommunications regulation bodies</a>)</li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/16px-Telecom-icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" 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title="Category:Telecommunications">Category</a></li> <li><span class="noviewer" typeof="mw:File"><span title="List-Class article"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Outline_of_telecommunication" title="Outline of telecommunication">Outline</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" 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