Border blaster
A border blaster is a licensed commercial radio station that transmits at very high power from one nation to another. Border Blasters should not be confused with international broadcast stations.
The term is perhaps most widely used in the United States of America to describe radio stations broadcasting from various Mexican cities near the border; however, the term is also widely used in the U.K. and Ireland.
With broadcasting signals far more powerful than U.S. stations, the Mexican Border Blasters could be heard over large areas of the U.S. from the 1940s to the ’70s, often to the great irritation of American radio stations, whose signals could be overpowered by their Mexican counterparts. These are also sometimes referred to as X Stations for their call letters: Mexican stations are assigned callsigns beginning with X, whereas American stations begin with the letters W or K and Canadian stations with C or VO.