This version of the 49er active bridge shows the signal strength as an "S meter" reading. As the Arduino Uno has a 10bit analogue port, the "S meter" reading ranges from S0 to S9+6dB. If the Arduino Uno is interfaced with a 16bit adc, then use the alternative code listed in the "void rx_pwr()" subroutine. A 16bit adc would give an "S meter" reading from S0 to S9+42.33dB.
The S meter rises in an S point for every 6dBV increase between the adc numbers from zero and 1023 with the 10bit Arduino analogue port. Similar would be with a 16bit adc port, with the numbers ranging from zero and 216 . The Adafruit ADS1x15 single ended 16bit ADC offering would do well to serve as the 16bit ADC conversion chip for the Arduino Uno on the two wire "i2c" interface. The Adafruit website illustrates the driver code include file as well as worked examples. in my active bridge code, I have put the 20*4 line display on the i2c line, so the adafruit adc board would connect also on the i2c line, meaning that both the adc and display would be data selected for their use on the i2c wire data network. Should this overall slow down the software reaction time for the active bridge, then reduce the overall sampling delay command found in the void(loop) main subroutine.
The sample voltage for the "S meter" could be taken from the radio agc voltage on the I.F. stage gain signal, however to match the measurement or calculation range of either the 10 or 16bit code, 10bit = S9+6dB, and the 16bit code = S9+44dB, then the dynamic range of the AGC amplifier really needs to match where possible the Arduino code. The 10bit "S meter" is essentially a 60dBV (S9+6dB) range while the 16bit code is an overall 96dBV (S9+44dB) range, so perhaps one could see the requirement from the AGC amplifier to match the Arduino code to hopefully produce a matching signal input to "S meter" reading come calculation. On the ADC numbers, a value of 500 reading comes out as 54dBV, or an S9 on the "S meter" on either the 10bit or 16bit ADC conversion.
In this example, the PTT and CW key lines are not used, hence the measurements that are displayed would in synch with the transmitter and receiver switching. By this, the vaild readings of the RX signal or the TX output along with the antenna loading, would only be valid within each of the Rx/Tx switching. Otherwise, the readings outside of the Rx/Tx switching would display a zero reading of the Rx input and Tx output, The antenna loading would perhaps still give a reading which from test would illustrate a perfect antenna load, as both the forward and reflected signals would balance out at a zero voltage measurement for each signal sense wire of the forward and reflected signal voltages.
The below url link is my google drive download link for the "S meter active bridge". This version uses the Arduino Uno own analogue port, thus with the 10bit resolution, the "S meter" range is up to S9 + 6dB. A 16bit version with the ads1115 adc board is listed on a separate page labelled "active bridge v4".
https://docs.google.com/document/d/1aG2nlzZVIwWxqpuDwehA-dn-e1lTzuC6oMeRh6ZcXLI/edit?usp=sharing