I live in Oscoda Co, Michigan, and monitor the Michigan Public Safety Comms System (MPSCS). I have the ES-1098 set to display site info. I've noticed that I will hear/see local radio traffic through the Mio site as well as through the Genesee Co Simulcast site(s). The Mio site is normal/typical and is a couple of miles away. The Genesee Co system and site(s) are 5 counties away, and unlikely that I would hear that - but possible I suppose. In looking at RR I see that both systems use a common control frequency of 853.375 MHz but Mio has a NAC of 796 while Genesee has a NAC of 798. I'm assuming that when I see the Genesee Co display I'm actually receiving the Mio site, but I could be wrong. Is there any way to verify/program NAC codes for system site control freqs in the WS software, and would that prevent the confusing display? If there are no NAC codes then I suppose this could occur for other sites with common control freqs. I've searched through the software and only see where the freqs are but no ability to add NAC codes. Do the NAC codes act like a "PL" for the each site control freq?