Yes sir it is all on 1 feed even with Isabella so on the feed there is still a lot of dead time most counties up here might only get a few calls a day i have 10 priorty ch's set up for the FD plus you can not hear fire ground ch's unless you are a few miles away so the only FG you would hear would be Harrison Fire.
I have been watching it close to see if calls were being missed and it hasn't happened yet.
I live in 9 miles from downtown Harrison and about the same to Gladwin
I know that on some of the ch's come in weak that is an issue i can not help for exsample Clare county Fire uses 154.265 and so does Kalkaska County Kalkaska county has a lot of power in the towers so it will come thru when i was on Harrison Fire it came across our radios durring the fall and winter months.
Also with Mecosta county uses the 154.445 and so does Roscommon County which means Mecosta county will come in weak at times.
I have just added some Fire ground ch's for Isabella county we will see if i can pick them up from here if so you will be able to hear fire ground from Shepard Tribal Deerfield and Sherman Nottawa FD's