Because you will be using an FRS channel, you do not need a license to operate on it. However your GPRS radio may or may not transmit at the higher GPRS wattage on that channel which technically requires the license. Of course, no one will know any better, because the wattage still is not that high, and you are on an FRS frequency. Much less, no one will care.
I'll have my ham radio with me too and perhaps I'll bring along my CB so I can spy on the OSMC folks who like to talk behind everyone else's backs..
