Good info! I found the 172.475 MHz frequency a couple months ago and after listening a bit, like you, decided it was TVA. While I couldn't find anything in the Alabama frequency database here on RR, I did find this page in the Tennessee database:
The most complete database of radio communications data
www.radioreference.com
I was not able to find a Monte Sano in Tennessee so I believe this is likely Monte Sano mountain in Huntsville, AL as there are a ton of radio installations on Monte Sano, from weather to commercial TV stations.
I mostly heard dispatching from Knoxville but, admittedly, haven't tuned in lately. Everything was on Eastern Time.
Thank you both for sharing the information!