I appreciate Rich supplying the original post. I have some comments to share regarding his questions, and would appreciate any feedback from others ...
When I'm monitoring Pal 800, I have no problems with receiving Newport, Lancaster and Chester, and sometimes also have marginal reception of the Chester, Winnsboro and Union sites. I have only heard Med Center Air working through the Lancaster site on the rare occasions I have heard them on Pal 800, and on those occasions, they were enroute to Columbia or Augusta ... no local flights.
On some statewide trunking systems, there is a protocol to only use specific sites to work the system when an aircraft is above a minimum altitude. Otherwise, the aircraft may end up keying multiple repeaters, as frequencies are often reused among sites within a large geographic system. Florida's statewide system has this requirement in place, for instance.
Anyone know if there is such a restriction on the Pal 800 system ?
Med Center Air alerts their crews via pager (462.925 MHz. - CMC has a transmitter on a tower on Neely Store Road, which is east of I-77 and the Galleria Mall). CMC flightwatch also alerts crews via VHF radio on 155.325 MHz. ... I believe they used to have a remote receiver at Lake Wylie.
I believe MCA's primary communications mode in Lancaster, York and Chester Counties is still via contact with EMS and fire / landing zone personnel on VHF, with a patch to the P25 trunking on the York Co system.
In conclusion, if I was looking to hear MCA when they are south of the border, their VHF channel would currently be my first mode to monitor.