Land Mobile Radio Analyzer and Coverage Measurement Guide : NBFM Analyzer : 12 dB SINAD
 
12 dB SINAD
The LMR Master can measure FM receiver or radio sensitivity using the 12 dB SINAD procedure.
1. Connect the LMR Master Signal Generator Out port to the radio antenna port. Use attenuation as required and lock out the radio transmit button during this procedure.
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 fm_1khz_audio1 with a deviation specified by the radio manufacturer. 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, the current Tx Output level setting for the LMR Master signal generator, and current SINAD, which should be close to 0 dB.
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 12 dB SINAD.
7. Press the Turn Sig‑Gen ON main menu key to start the LMR Master transmitter (Figure: 12 dB SINAD with Signal Generator Off).
8. Increase the LMR Master Tx Output Lvl until the needle on the SINAD meter is near the center of the display and equals 12 dB (Figure: 12 dB SINAD with Signal Generator On and Meter Showing the SINAD Level). The power level displayed on the left side of the blue bar is the 12 dB SINAD level.
.
12 dB SINAD with Signal Generator Off
 
12 dB SINAD with Signal Generator On and Meter Showing the SINAD Level
1 For systems that require an unmute tone in addition to the audio for 12 dB SINAD testing, use one of the following Tx Patterns:

fm_1khz_ctscc (1 kHz audio plus a CTCSS unmute tone)
or
fm_1khz_DCS (1 kHz audio plus a DCS unmute tone)