Sports broadcasting's unofficial history began in 1921, when commercial radio was still in its infancy. The airwaves in the United States were primarily used for military communication, and broadcasting was not available as a mass media source of entertainment. Back in the day, most radio listeners were tinkerers who built their own radios out of trash. SportsCenter, on the other hand, may begin earlier and last longer if the preceding event concludes early or if breaking sports news necessitates it. Since 2009, the 1:00 a.m. Eastern edition of SportsCenter has been produced live from Los Angeles; this version is also rebroadcast throughout the night.