I have been picking these up on my BCD536HP scanner but have not paid attention
whether it was analog or digital. I'll look for them again and try to get back to you
at some point in the next few days.
Provided the RR DB is accurate, here is what I found when I visited the RR DB page for Houston. I went to "higher education" & founded both conventional & trunking talk groups for the University of Houston. The police seem to be operating on TxWarn MOT.
I haven't heard them either, but I do live in far west Harris County. I wonder if they went TDMA, like Rice has, and nobody with a TDMA scanner has searched for them.