Found this at Broadcast and Cable although it's from a vendor at CES. I like the fact that you can use your computer these days along with the necessary adapters to test things like this rather than having to pay big bucks for a stand alone unit.
Mobile DTV Test & Monitoring Application - Broadcast and Cable
So, you are currently deploying a Mobile DTV Head-End (ATSC-MH)! And setting up such a signal on-air is a tricky endeavor. The lack of devices makes it difficult to analyze precisely when something is out of tune. Expway Test & Monitoring Application will make it easy for you to analyze signal quality and to pinpoint errors in the streams. The package contains a PC application and an USB dongle, bundled to work hand in hand.