If you haven't listened in a while, fire channels 7 and 8 have been split apart.
Channel 7 used to be primary for districts 2 (City of Chester, 3 (Ridley Twp.) and 12 (Ridley Park, Prospect Park, Eddystone and Tinicum)
Channel 8 was the secondary channel for the same districts.
Now channel 7 is used by districts 3 & 12. Channel 8 is used by district 2.
This is all that I can think of. Hope this helps.