In east Texas just west of Tyler, daytime is a very weak signal from KMVL in Madisonville, mixing with their synchronized repeater, KM2XVL, a little over 25 miles down I-45 in Huntsville. (What makes this unique is that it's one of only two stations in the continental U.S. that has this sort of operation; the other one is the historic WLLH with its dual operation in Lawrence and Lowell MA).
At night it's Mexico City's XEB, with a steady, strong signal. Occasionally around sunrise and sunset a few low power stations creep in, including one from the Dallas/Fort Worth area, KZEE in Weatherford.