Back to the original question, you can hear CoMIRS digital on the whole length of I-91. Wilbraham (site 1.27) covers well up to about where I-91 starts to carve into the mountains in Holyoke, then the North Simulcast will come in. Also the South Simulcast also covers a large part of the same area. I suspect you have a programming issue as well. As @cg said, the system is TDMA (Phase II) capable, and there are a bunch of Phase II talkgroups being used in the Worcester area, but Western Mass remains all Phase I. When CoMIRS gets finished being built out, the large "area wide" talkgroups are going to be broken down further to more regional ones. The last document I saw had more B-PTL groups listed. (Over B-PTL-1,2,3.)