TRC233 s meter addition

the squelch control feeds an op-amp that is the cutoff for the receive audio.  the ALC feeds the squelch knob.  follow that back to a transistor and resistor, the resistor pulls the line up to +8, and the transistor pulls it down as signal strength increases.  place the meter in parallel with this pull-up resistor.  a 10k multiturn mini potentiometer in series will adjust most meters to read full scale at receive saturation.  You may need to short a drop resistor in the meter if it comes set to measure volts instead of millivolts