2. Adjust the TX Power Offset to account for the attenuation loss in the Signal Generator path.

3. Connect the LMR Master Audio In port to the radio loudspeaker or audio out connector (Figure: Setup for 20 dB Quieting and 12 dB SINAD).

4. Set the LMR Master Tx Output Lvl to the minimum level (which will be –130 dBm + the value entered for Tx Power Offset) and the Tx Pattern to cw. Set the LMR Master Tx Freq to the radio receive frequency. Confirm that the LMR Master signal generator is Off (menu key displays Turn Sig‑Gen ON).

5. On the LMR Master, press Measurement > NBFM Quieting (twice). The LMR Master displays the current voltage at the Audio In port and the current Tx Output level setting for the LMR Master signal generator.

6. Turn on the radio and set the radio audio level to the manufacturer’s rated audio output level. The RMS voltage level present at the Audio In port is displayed below the meter for convenience. Refer to the radio maintenance manual to determine this level. This is the audio level used for measuring 20 dB quieting (Figure: 20 dB Quieting, Ready to Set Reference Level).

7. Press the Set Reference key and note the Reference Level voltage displayed on the right side of the blue bar as shown in Figure: 20 dB Quieting After Increasing the LMR Master Sig‑Gen Tx Output. Setting the reference will automatically adjust the voltage scale such that the voltage displayed in the middle of the meter is 10 % (–20 dB) of the reference audio voltage.

8. Press the Turn Sig‑Gen ON main menu key to start the LMR Master transmitter.

9. Increase the LMR Master Tx Output Lvl until the needle on the voltage meter is in the center of the display (Figure: 20 dB Quieting After Increasing the LMR Master Sig‑Gen Tx Output). The Audio In voltage level has decreased to 10 % of the reference level. The power level displayed on the left side of the blue bar is the 20 dB quieting antenna input power level.