The radio station was heard on the clear channel frequency of 640 AM, powered at 50,000 watts, making it audible around the Caribbean and Southern United States at night.

The CMQ 640 radio studios were initially located on Calle Monte, on the corner of Paseo del Prado.

On March 12, 1948, the studios and offices were moved to the Radiocentro Building on La Rampa and Calle L in El Vedado.

Regular commercial broadcasting began in October 1950 with Gaspar Pumarejo's Unión Radio TV.

[2][3] At the beginning of the 1950s, the transmission of the telenovela El Derecho de Nacer, by Felix B. Caignet, proved popular with audiences.