Yes they were on the old Wireless USA 900mhz analog system. When WirelessUSA upgraded the old analog to DMR MEDSTAR didn't move to DMR and I BELIEVE went to a 900mhz repeater located at the Fairview Heights Site. On the old 900mhz analog trunked system it actually worked very well for them but I think you're right, when they went to the repeater they started to have a lot of issues. I know that Fairview site doesn't reach well south of the site because of the topography. This of course was mostly the St. Clair County trucks as the Randolph and Clinton County trucks were all on VHF.
What's really interesting about MEDSTAR is even with all those different systems in different transmitting locations they were all dispatched out of Sparta (Headquarters). I know the Clinton county trucks are dispatched by Clinton County (sometimes or all the time? don't know) but they still talked to MEDSTAR dispatch somehow down in Sparta.
If you searched Medstar FCC licenses they used to maintain several different frequencies of VHF, UHF (MED channels), and 900. I imagine going to STARCOM they can abandon all of those.
I have it on good authority that the migration to STARCOM will be all trucks, supervisors, and admin regardless of county. Some ENC on specific Talkgroups but Dispatch SHOULD be all clear. Each county will have it's own talkgroup. So a St. Clair County TG, Randolph, and Clinton County. I have no idea if those will be sub divided by region like Belleville, East St. Louis, etc. If all the St. Clair County trucks have one talk group, I can assure you that TG will never be quiet. I hope they tweak the dispatchers audio because the trucks sound great but the dispatchers right now seem to have a lot of background noise and it's hard for me to understand them. Might be them not using headsets and using desktop mics during migration as I think at times they're using new and old to dispatch for right now.