It all depends on the type of antennas. My thought would probably be as ecps92 mentioned. Another thought is possibly that the Maine Forestry or DEP allows them on their system or possibly they have radios to communicate with local fire departments. Law enforcement and the like have certain types of antennas mounted in a certain pattern that is usually uniform with all the vehicles. This includes Forestry, DEP, Marine etc. of which the Maine Nature Conservancy works along with. My last thought is that they possibly could be on a radio system that is owned by a larger radio communications service such as Atlantic Communications, in which case, you wont figure it out unless you work for them.