I noticed Nicor Gas was using NXDN on the Ops 7 (451.975) Channel about a month ago. About a week or two ago I put it in its own single freq system to obtain a TG ID# off of the channel. I came to find out that there were about 30 different TGs displayed on the freq as of this week. I got to thinking that the (451.975) Ops 7 Freq could be a control channel as I never heard traffic on the other freqs that are currently listed in the Illinois Utilites (Area Wide) database. How could I find out if I on to something and this could be a large NXDN System of their own?