Also, slightly off-topic, and this is just for Chester County, but I recently found a site that lists active fire, police and EMS dispatches. Pretty useful for checking road conditions or if you hear a siren and want to know what's going on. It's really starting to get busy out there--normally there are only a handful of dispatch calls out. Check it out:
https://www.chesco.org/3963/WebCad-Active-Incidents