Specification for a GE Mastr II receiver is .5 micro volts for 20 db quieting. For approximate check, put an AC volt meter on the speaker with squelch open. For example, if voltage is 1.2 volts and you supply .4 mv on receive frequency to the receiver in order to get the voltage down to .12 (a factor of ten) that means your receiver requires .4 volts for 20 db quieting. Adding a preamp with ban pass cavity in front will give even better results. I always get better results than the specifications.
2 meter repeater CURRENTLY ON BISKY:
60 watts into duplexer 45 watts out
.398 µv for 20 db quiting into receiver
.15 µv for 20 db quitting into band pass cavity and Pre Amp
2 Meter Backup Repeater 11/13/17
.500 µv for 20 db quitting into receiver
.112 µv for 20 db quitting into band pass cavity and Pre Amp
Added 9/4/2017 - Adjusting the power on the GE Maastr II.