Thanks for posting this and updating the database.
I did not know about the UHF frequency being allocated as well. That makes perfect sense as 453.750 seems to be the standard talkaround or fireground frequency for the many fire departments on the Forestry RCFP system. If the RCFP fireground channel uses a common tone across counties, or is CSQ, then radios on the system will not have to be reprogrammed just to add the new UHF Air Ambulance Net.
The VHF Air Ambulance Net should be very useful also. In addition to decreasing the amount of traffic on the HEAR system, it is being pushed as the standard statewide channel for ground units to interop with EMS helicopters. I suppose the HEAR channel (155.340) was originally supposed to be used for this purpose, but in my experience only a few EMS agencies used it as such. On scene flights, most communications centers in my area direct EMS helicopters to use the local departments primary channel, often with mixed results. Having one statewide channel should dramatically streamline things, and flight crews will no longer have to worry about what the "Old analog West fire repeater", or the "New Podunk fireground channel" is.
Unfortunately, the new frequency(s) was not really publicized. Marion County did not know anything about it until October, when an Air-Evac spokesman came to a fire association meeting and discussed it. Thankfully, this was just a few weeks before we narrowbanded all of the fire department radios in the county; so we simply added the channel then. Walker County, on the other hand, had already converted to narrowband before they found out about it; and did not want to pay to have their 300+ fire radios reprogrammed again just to add the new channel. I don't know how many other counties did or did not add the channel to their radios.
In reference to the RR database, the new frequencies (and indeed all of the channels on the "Common/Shared" page) are narrowband FM (FMN), instead of wideband (FM). I don't know for sure about the UHF channel, but the VHF Air Ambulance Net is carrier squelch.