Editing History of broadcasting (section)

=== Mexico ===
Amateur radio was very popular in Mexico; while most of the hams were male, notably Constantino de Tarnava, acknowledged in some sources as Mexico's first amateur radio operator,<ref>{{cite book|first=Marvin|last=Alinsky|year=1988|title=International Handbook of Broadcasting Systems|publisher=Greenwood Press|page=215|isbn=9780313243486}}</ref> one of the early ham radio operators was female—Maria Dolores Estrada.<ref>"Mexican Girl Gets First Grade Commercial License." QST, January 1917, p. 49.</ref> But commercial radio broadcasting was difficult to achieve, due to a federal regulation forbidding any broadcasts that were not for the benefit of the Mexican government. Still, in November 1923, CYL in Mexico City went on the air, featuring music (both folk songs and popular dance concerts), religious services, and news. CYL used as its slogans "El Universal" and "La Casa del Radio", and it won over the government by giving political candidates the opportunity to use the station to campaign.<ref>{{cite journal|first=Susan|last=Haymes|title=A Junket to the Mexico City Studios of CYL|journal=Radio Digest|date=November 14, 1925|pages=7, 12}}</ref> Its signal was so powerful that it could sometimes be received in Canada.<ref>{{cite news|title=Novel Programs from CYL Mexico|newspaper=Toronto Globe|date=December 9, 1925|page=9}}</ref> Pressure from listeners and potential station owners also contributed to the government relenting and allowing more stations to go on the air.<ref>{{cite book|first=Marvin|last=Alinsky|year=1988|title=International Handbook of Broadcasting Systems|publisher=Greenwood Press|page=216|isbn=9780313243486}}</ref> In 1931, the "C" call letters were all changed to "X" call letters (XE being reserved for broadcasting), and by 1932, Mexico had nearly forty radio stations, ten of which were in Mexico City.<ref name="Cuban and Mexican Broadcasters"/>