Check to make sure all service types are active. Fire Dispatch/Fire-tac/EMS-Dispatch/EMS-tac/hospital etc'. It seems to be the most overlooked setting on these 436/536 scanners.I just did all this for my 436 and the audio has improved, a lot, and I'm getting more hospital traffic, but I don't think I'm getting all the fire traffic. Any ideas? BTW you can get the firmware update via Sentinal. I'm going to bump the threshold up to 10 and see what happens. Thanks this was a big help.