1. On the LMR Master, press the Menu key then select the NBFM Analyzer icon or press Shift and then the Mode (9) button to open the Mode Selector dialog box. Highlight NBFM Analyzer and press Enter.
Caution
The maximum input power without damage is 2 watts (+33 dBm) to the RF In 50 Ohm connector. To prevent damage, use the Anritsu MA25200A High Power Tx/Rx Input Protector (High Power Input Protection), a coupler, or an attenuator to reduce the input power to below this level when measuring high output power devices.
2. Connect the transmitter to the RF In50 Ohm connector on the LMR Master using a high-power protection device, or connect an antenna with the appropriate frequency range to the RF In50 Ohm connector on the LMR Master.
3. Press the Amplitude main menu key, then the Rx Power Offset submenu key to set the attenuation (or gain) of any devices between the radio under test and the LMR Master. Use the arrow keys, rotary knob, or the numeric keypad to enter the adjustment value, up to 100 dB, and then press either the Loss or Gain submenu key. The offset will be applied to the Carrier Power value in the Summary graph. For instance, if the transmitter under test is emitting 50 watts (+47 dBm) of power, and the External Attenuation value is 40 dB (such as from a 40 dB directional coupler), then the Carrier Power displayed will be +7 dBm.
4. Press the Frequency main menu key to set the LMR Master receiver center frequency (Rx Freq) of the measurement. Use the arrow key, rotary knob or the numeric keypad. When using the keypad, select the appropriate terminator submenu key to set the center frequency. A second option is to use Auto Scan under the Setup main menu. Turn Auto Scan on and key the radio or transmitter. Auto Scan will find and display the highest power signal above +10 dBm (10 mW) between 10 MHz and 1.6 GHz in the center of the Spectrum graph. After the signal is found and displayed, set Auto Scan to Off to stop the LMR Master from scanning for a new signal.
Note
Typically, the Auto Scan feature will only work if the radio is cabled to the S412E. There is a lower‑limit to the amount of power needed to make Auto Scan respond; the requirement is just above +10 dBm (10 milliwatts). This is the raw port level, the requirement increases by the amount of attenuation caused by the RF In protection device.
5. Press the Setup main menu key to select the tone type. Select CTCSS, DCS, or DTMF using the Tone Type key. Press the Filters submenu key and set the intermediate frequency bandwidth (IFBW) and bandwidth percentage (% IFBW). Filter the audio signal using the Low Pass Filter or High Pass Filter.
6. Press the Measurement key, then the NBFM Analyzer submenu key. Refer to NBFM Analyzer Graphs for information on the available graph types.
Note
Many of the displayed settings on the left side of the screen are used as menu shortcuts. Select a setting using the touch screen to display the menu and set the parameter for editing.