I know that you are new of this Radio Reference.com, but you posted the question in two separate posts on the Maryland Forum. It is considered bad manners to double post questions on this board. You must remember that it may take some to time to have your question answered, since people have other things to do like work and don’t sit at the computer 24/7 waiting for posts to show up.
I don’t have the any information on Frederick County, since only monitor them when in the area for work. I wouldn’t purchase any analog scanners anymore, since many systems are changing to digital everyday.
Larry