There appears to be a digital system operating in the 380-400 mhz range near Piedras Negras, Coahuila State.
Sounded like a control channel on 393.8625.
The following were active with carriers, digital signals and sounds similar to a fax machine connect tones: 384.6250, 384.7000, 384.9250, 385.000.
Clear voice comms on 386.2750, "azul con limon" then nothing.
The following, not related to the above network, were active with clear voice comms: 170.325, 165.625, 163.825, 163.575, 167.0125, 164.6375, 164.675 (very active), 411.575, 415.675.
Sounded like a control channel on 393.8625.
The following were active with carriers, digital signals and sounds similar to a fax machine connect tones: 384.6250, 384.7000, 384.9250, 385.000.
Clear voice comms on 386.2750, "azul con limon" then nothing.
The following, not related to the above network, were active with clear voice comms: 170.325, 165.625, 163.825, 163.575, 167.0125, 164.6375, 164.675 (very active), 411.575, 415.675.