FWIW - I know the focus is on TXWARN in this post, but for EMS/Public Safety related, I remember (2005-06ish) I used to hear 462.175 Careflite ground units down that way (can't remember the PL as I no longer monitor this freq). I remember I could copy it very well though when I lived in Flower Mound with an outside antenna on the chimney, so the repeater had very good coverage at the time. However, I don't know what areas Careflite covers there, or there contracts for ground.