While listening to Delco Fire 4 (107.2 PL) I was hearing some background noise. So I pressed function + tune to see what it was. It came up the same frequency with a 100.0 PL. Sounded like police talk concerning notifying electric company. I did a license search in PA and NJ. PA the only thing that came back was Delco. In NJ I got these back. New Jersey Scanner Frequencies and Radio Frequency Reference They are all listed as industrial business pool private trunked. Any idea what this 506.5125 PL 100.0 is? I will continue monitoring this.