chicago pd

Hello everyone. I do hope this is the correct thread to ask a question about a TGID. I was talking with a CPD officer today at ORD checking the current TGID: 49872 on the Chicago Public Safety system at O'Hare. When the CPD officer keyed up and talked, I was not catching the TX. When dispatch...

So I have had a few scanners over time and tried listening to CPD, and I can hear all transmission, but on dead air both my scanners give an awful beeping/static sound. its not constant, but sporadic. Any ideas on what is going on and what I need to do to get rid of it?