When I lived in Northern Colorado years ago (5) I programmed in the FE Warren trunked system and as I recall most talkgroups
were encrypted. I now live in Central MT. and programmed in Malmstrom AFB trunked system and it also is encrypted.
I believe the Missile Wings use full time encryption based upon their mission.
A couple of the frequencies that I do monitor and hear traffic on are the missile wing rotary wing aircraft, UH-1’s,
They use the callsign “Blade XX”, 271.9 and 308.8 am.
FWIW they will be getting rid of the UH-1’s and transitioning to the MH-139 helos within the next year and half.
73, Rex