Welcome to the RR forums. Chicago PD are fully encrypted and cannot be monitored as denoted by mode "P25
E" in the database
View attachment 158600
Regarding law enforcement in the suburbs, etc. Consult the
database & it will tell you who operates where. Focus on the "Mode" column. Any time you see an uppercase "E" (as in DE, TE, P25E, etc) this denotes full encryption meaning the frequency or talkgroup cannot be monitored.
Additionally the HomePatrol-2 and most supported scanners (aside from the Uniden SDS100 & SDS200) are prone to
simulcast distortion which you'll likely face when monitoring
Cook South - Simulcast or the Chicago
Citywide Simulcast on STARCOM depending on your location relative to two or more simulcast cells. Feel free to click the text "simulcast distortion" above for multipath mitigation methods if you do indeed encounter this but ultimately you'd be much better off with the aforementioned SDS models to bring in traffic on simulcast systems