Actually, Grand Isle County for the most part abandoned 154.190 several years ago and went to their own 800 conventional system. Dispatch and operations is on 868.500 MHz., and paging, which is now done by Contact Dispatch, is done over their 152.480 digital paging network. This was one of the last things I did on the county's emergency services committee before I left Vermont.
Alburg Fire & Rescue, with Isle La Motte Fire to a lesser extent, are the only ones still using 154.190 but only for car to car use. This will be changing as they have a grant to expand their VHF system to include a new repeater and possibly a voted receiver system.
Also, Alburg Fire & Rescue have Motorola 800 MHz. Smartnet radios (Maxtracs or MCS2000) installed in almost all of their apparatus, as well as a control station in the radio room and I also believe one portable which they take when they go to Clinton County for a call. Isle La Motte did not buy any mobile radios, but do have at least one portable radio, which they also use when responding mutual aid to Clinton County.
Time was all of the 800 towers were linked together and simulcasted all traffic so that no matter where in the county you were, you would hear your traffic. I guess there would be a logical reason why they turned this feature off, but I honestly don't understand why except possibly to keep radio traffic 'localized' within each zone or tower, in order to re-use the same frequencies in the system at different towers with different conversations, in order to increase the system capabilities (that was always an issue in the past, too many users and not enough frequencies in the system). I guess then that all of the TAC-1 talkgroups are assigned to the Champlain & Churubusco towers, TAC-2 talkgroups to Rand Hill and TAC-3 talkgroups to Terry Mountain, unless the entire fire/ems system was changed. Personally, I liked it when I could be in downtown Plattsburgh and listen to a working fire in Rouses Point.