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2-2 Transmitter Analysis Setup Chapter 2 — NBFM Analyzer
2-2 PN: 10580-00243 Rev. F Land Mobile Radio MG
Anritsu also supports narrowband digital transmitter Land Mobile Radio technologies
including P25 (Chapter 3), P25 Phase 2 (Chapter 4), NXDN (Chapter 5), DMR 2 (Chapter 7),
and PTC, Positive Train Control, (Chapter 8).
The LMR Master will analyze input signal strengths from +33 dBm (2.0 watts) down to levels
approaching the sensitivity of LMR radios, automatically adjusting the analyzer input
sensitivity based on input levels.
2-2 Transmitter Analysis Setup
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.
2. Connect the transmitter to the RF In 50 Ohm connector on the LMR Master using a
coupler or attenuator or connect an antenna with the appropriate frequency range to
the RF In 50 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.
5. Press the Setup main menu key to select the tone type. Select CTCSS, DCS, or DTMF
using the To n e Ty p e 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
.
Caution
The maximum input power without damage is 2 watts (+33 dBm) to the RF In
50 Ohm connector. To prevent damage, use a coupler or attenuator to reduce the
input power to below this level when measuring high output power devices.
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.