Wikipedia
XHTAO-TDT
XHTAO-TDT channel 47 (virtual channel 6) is a Multimedios Television affiliate in Tampico, Tamaulipas.
Before the analog shutdown XHTAO's audio signal could be heard at 87.7 MHz on FM radios, though at a slightly lower volume than other FM stations, due to technical reasons. After the analog shutdown this couldn't been possible due to the nature of digital TV.