The FCC has designated the two radio services viz. FRS and GMRS. None of these services are signed for exclusive use of any user. Users can improve the services by minimizing the interference levels. To avoid the interference, only one user should use the channel at a given time. The FCC regulations are not the same for all the channels, and some channels may work better than others.
The FRS or Family Radio channel consists of 14 channels with low signal strength whereas GMRS channels comprises of 23 channels with low to moderate power. Both FRS and GMRS, share seven channels between them with the only difference of power levels. Out of 23 GMRS channels, eight channels are reserved for repeater stations to relay the signals. You have to check with the radio brand for the coverage area of repeater sites in order to use repeater services.