To answer the question for the VHF antennas.
According to OEMS in Raleigh, all ambulances in North Carolina must have the capability to communicate with comm centers and hospitals in the state.
All communication centers in the state are supposed to have and be able to monitor the frequency 155.280 Mhz.
All hospitals in the state are supposed to have the frequencies of 155.340 Mhz and 155.280 Mhz.
I think there are some exceptions to this rule. I know Mecklenburg Co. EMS in Charlotte does not have VHF radios, they only have 800 Mhz.
The key is to having some form of communications with the hospitals whether it is VHF, UHF or 800 Mhz. I don't think the state really cares as long provides have communications with recieving hospitals.
I do know that the following frequencies are for NC State wide usage:
155.280 Mhz Vhf Statewide Calling
155.340 Mhz Vhf Statewide Hospital Encoding
462.975 Mhz Uhf Statewide Calling (Med-10)
Hope this helps
David