Chris Ranck forwarded this message from CARMA Chicago:

Subject: (CARMA) Re: Confusion: 151.4075, Tri-Com dispatch to Sugar Grove FD?

When I first learned of “Tri-Com South” for North Aurora & Sugar Grove FD, my source told me that both agencies were going to be using 154.7925 D174, the former Sugar Grove FD repeater. However 151.4075 D654, the former North Aurora FD repeater continued to be operational. At first, back in April, both repeaters sounded to me like they had technical issues. The Sugar Grove repeater sounded too “digital” on the dispatcher side, and the North Aurora repeater had flakey modulation levels. But ever since then both repeaters have sounded great. So it appears that Tri-Com South is actually a simulcast system, with the dispatcher and each agency’s traffic being sent to each transmitter. I am awaiting confirmation that North Aurora mobiles are still using their original input but I would assume that they are.

Tri-Com South (Fire)
154.7925 D174 Sugar Grove transmitter
151.4075 D654 North Aurora Transmitter