sentences:  While XERF's concession remained with Compañía Radiodifusora de Coahuila, the actual control of the airtime and the management of the facilities in Ciudad Acuña were under the control of Inter-American Radio Advertising.The Texas company purchased a 250,000-watt RCA transmitter to beam an omni-directional clear channel signal on AM 1570, which originated some distance from the old XERA facilities within three new prefabricated concrete buildings with flat roofs.The sales brochure for XERF offered this explanation about the operation of the station (emphasis and wording shown as in the original text)