A historical note about TG's 1917 and 1918: 1917 and 1918 were allocated for (what was then at the time) Banner Health's AirLife of Greeley air ambulance service based out of NCMC. At the time, aircraft were restricted from accessing and using the DTRS, so these talkgroups were only for ground operations. 1917 was "AIRLIFE" and 1918 was "AL RUN-1" (based on my notes from when I was both a CommTech and EMT up that way about 10-15 years ago). I never heard any traffic on those TG's in all the time I lived and worked up there, though. Flight following was on MED 3 and biophone patching to MCR and PVH was on MED 2. This is, of course, all historical data now though.
I've never heard TG 153 used for air medical purposes. It appears to still be active, as I've logged affiliations for it recently on Thorodin, Squaw, Smoky Hill, and Douglas North Simulcast. My hospitals TG table has it allocated as "ANSHUTZ HSP." Over the years I've heard it sporadically used for ground transport ambulances and also for what sounded like security operations at one point in time, but haven't heard any activity on it recently. It appears to be denied off of DTB and Chevron, so perhaps I'm not paying attention to the right sites anymore to catch traffic on it.
I still hear aircraft and CCT (ground ambulance) traffic daily on "MED 9" for AirLife Denver and on "D&C 10" for Flight for Life in the metro area. Both frequencies are analog, in the clear, and carry flight following and biophone patching traffic regularly. MED 9 and D&C 10 are also used by other outside air ambulance companies for biophone patching depending on which hospital network the destination hospital is in (MED 9 for HCA/HealthOne hospitals, D&C 10 for Centura hospitals). SACC also uses MED 8 as a backup to D&C 10 in the metro area when the Squaw Mtn site is down or has poor signal. V-FIRE21 is the favored ground contact frequency for Flight for Life in Jefferson County and also used for comm center-to-comm center traffic between both Jeffcom and SACC.
