Nomad is absolutely right.

Simply put: Both the user and the device must meet FCC regulations in order to transmit legally on a given frequency.

Ham radios are not type-accepted to transmit on FRS, GMRS, MURS, Maritime VHF, or any other non-ham frequency allocation in the USA.

Edited to add: I possess both a GMRS and an amateur radio license. I cannot legally use my GMRS privileges to transmit with a ham radio transceiver.