Charles E. Apgar
... that amateur radio operator Charles E. Apgar's recordings of radio transmissions during World War I were found to include covert messages that exposed an espionage ring?
... that <a href="./Amateur_radio" id="mwBKM" rel="mw:WikiLink" title="Amateur radio">amateur radio</a> operator <b id="mwBKQ"><a href="./Charles_E._Apgar" id="mwBKU" rel="mw:WikiLink" title="Charles E. Apgar">Charles E. Apgar</a></b><span about="#mwt56" class="nowrap" data-mw='{"parts":[{"template":{"target":{"wt":"`s","href":"./Template:`s"},"params":{},"i":0}}]}' id="mwBKY" typeof="mw:Transclusion"><span typeof="mw:Entity">'</span>s</span> recordings of radio transmissions during World War<span id="mwBKc" typeof="mw:Entity"> </span>I were found to include covert messages that exposed an <a href="./Espionage" id="mwBKg" rel="mw:WikiLink" title="Espionage">espionage</a> ring?