They just posted this news article that MCSO, MCEMS, and County Fire are planning to switch to the current P25 system that Clarksville already uses soon. They will not be on NXDN anymore. The switch will be occurring over the next two years or so. They are planning to build a new tower for coverage in the county.
clarksvillenow.com

Montgomery County one step closer to construction of new radio tower for public safety departments - ClarksvilleNow.com
In an effort to improve communications between county and city public safety departments, the County Commission approved a long-term lease agreement for a portion of land in southwestern Montgomery County to construct a radio communications tower.
