Yes - there is a site on a system in Maryland where when I last looked, only the control channel frequency was active and when the only user talked, they took over that frequency. The CC returned when they were done talking.I'm monitoring a NXDN trunk system which is part of a network in eastern MA. One site seems to operating as a single frequency trunk as the control channel data is also a voice channel.
Has anyone else seen that sort of activity?
Not the same thing but I've monitored another system that used the control channel frequency as a voice overflow when all other frequencies on the system were in use.