I have a repeater made from 2 old Motorola MCS-2000 radios. Coverage is good on transmit, but the receiver radio seems to have only mediocre sensitivity. I was wondering if an external FET preamp could be installed between the receiver radio and the duplexer, to make the repeater "hear" better. I know us hams use preamps for weak signal work on 2m, seems it could be done on FM on GMRS....