On approach you always get the ol' "RADAR services terminated" call as you pass 8500'
That's not right.
The phrase used is "Passing A085
Control Services are terminated" ......because you are leaving Class E airspace and entering Class G airspace.
Radar coverage at BNA down to about circuit height, but reliably around A020.
To the west of BNA the ranges to the south of YBCG interfere with the radar head image from Mt. Somerville and we often lose aircraft at about A035.
When you tell ATC you are transferring to the CTAF or ATC lose ident, you will be told by ATC "Identification Terminated".