Well the FCC does allow GMRS repeaters. I have yet to figure nd a single repeater, that is actually not a part 90 device. So from my POV amplifiers are just fine to use with a GMRS radio. The antennas are made to be removable and allow the use of different antenna configurations. So personally I do believe the FCC does allow the amplifier use. JMHO The thing is though... The max allowed power that can be used on GMRS frequencies is 50watts. No matter if your using a Ht, a mobile, base, or repeater. 50 watts is max. Midland makes a 40 watt mobile. The only value that an amp would use is to take your HT to 50 watts. The Btech amp, which will work on GMRS frequencies will only go to 40 watts. So I think you will be safe!