They use:
155.34000 Various BM CSQ EMS 3 Statewide Common EMS (Most common EMS to Hosp and Life-Flight FM Hospital
You may only hear them call in for report here and there because most services use cell phones more frequently now than radios..
They helicopter pilot will stay in comms with the main hospital in Sioux Falls on their proprietary freqs,
Sanford will either be on:
18320 479 D Trauma 1 Sanford Health Trauma 1 Hospital
18336 47a D IntensiveAir Sanford Health Intensive Air Hospital
Avera will be on:
8304 478 D Care Flight Care Flight - Avera McKennan Hospital OR
462.95000 WNGG479 RM 162.2 PL Avera Hosp Avera McKennon Hospital FM Hospital
If I remember right Avera will use the analog freq of 462.950.. cant remember which DIG TG Sanford uses. I think Avera may even have their analog freq and their DIG TG patched... cant remember.
Have fun