Streaming, my friend, streaming.
I know that you can stream the broadcasts online but my point was that if you are just taking a sample of people listening over either the FM or AM airwaves, you'd get far more listeners from the opponents of Southington than you would from the opponents of Cheshire.
Most people are first going to find out about the broadcasts by hearing them when passing by 96.1 or 990 on the dial in their car, and then after that check to see if the station streams online. So you would bring more listeners in overall (both online and over the air) if the FM/AM's coverage range is better in the first place, and you choose a team that plays opponents which are mostly in that coverage area.