I see two frequencies listed for Calumet City ESDA:
856.21250 and 155.055
You're going to need a 325P2, 436HP, or SDS100 to be able to scan the 800MHz frequency. If you want to receive the Starcom trunked system, the SDS100 is your best bet, because Cook County uses simulcast, which the other units have difficulty receiving. But it is the most expensive--$650 new.