A little more info would help us help you. I am sure Atlanta has a whole lot of different systems. What have you loaded and what do you want to hear. Put in a weather frequency and make sure that works.
The Atlanta TRS is Phase I and pretty straight forward. I don't see to much encryption. The system is however a simulcast system. Depending on your location, you may be having the LSM distortion issue.
You'll have to read up on that. It can make you loose a few hairs. If all your settings are correct, that's is likely your problem. These consumer grade scanners don't do well with simulcast transmissions.