MASTR III Repeater Calibration Procedure 5/16/2011 1 Repeater Configuration 1.1 Radio Programming The radio should be programmed using the Harris MASTR III Control Shelf Programming application M3.BAT (MS-DOS batch file) using a standard RS232 serial cable connected to the MASTR III Data Port (Left Receiver or Right Receiver) and the host PC. The Bandwidth should be set for 12.5kHz Narrowband operation. Default factory settings are used for all other parameters except as required by the user. 1.1.
MASTR III Repeater Calibration Procedure 5/16/2011 Connect the equipment as shown below: Radio Under Calibration P25CC Aeroflex 3920 Tx T/R 50 ohm coax CAT 5 P25CC Radio Interface Cable PCCT Calibration Software PC Figure 2-1 Equipment Setup Raytheon JPS Communications, Inc.
MASTR III Repeater Calibration Procedure 5/16/2011 2.1.2 Initial Steps 2.1.2.1 Set the Radio Test Set to analog duplex mode and program to monitor the frequency of the transmitter. 2.1.2.2 Power up the radio and P25net CC. 2.1.2.3 Launch PCCT and connect to the P25net CC channel. 2.1.3 Radio Tx Calibration 2.1.3.1 In PCCT go to the Configure >Tx window and select Analog Sine Wave per Figure 2-2. Preset the Tx Gain and Offset Pots to the values shown.
MASTR III Repeater Calibration Procedure 5/16/2011 2.1.3.2 Start a Sine Wave test tone in PCCT and adjust the Tx Gain for approximately 2.8kHz as read on the test set deviation meter (Figure 2-3). Adjust the Tx Offset to as necessary to get the correct transmit frequency (minimum offset). The Tx Gain and Offset Pots are interactive so this will require some iteration to get the proper settings. Once you have made coarse adjustments, use the TxVcoGain and TxVcoOffset Pots for finer steps.
MASTR III Repeater Calibration Procedure 5/16/2011 2.1.3.3 Change the test tone selection on PCCT to Analog Short Square Wave (100Hz) and verify the demodulated audio oscilloscope displays a good approximation of a square wave with generally flat high and low levels (Figure 2-4). A poor square wave indicates the radio needs to be aligned with the factory service software to achieve better DC Balance. Figure 2-4 Test Set Oscilloscope: Short Square Wave Raytheon JPS Communications, Inc.
MASTR III Repeater Calibration Procedure 5/16/2011 2.1.3.4 Reconfigure the test set for P25 mode. 2.1.3.5 Start an IMBE test tone using PCCT set to Standard Tone Test Pattern. Figure 2-5 Standard Tone Test Pattern Raytheon JPS Communications, Inc.
MASTR III Repeater Calibration Procedure 5/16/2011 2.1.3.6 Listen for a 1200Hz sine wave in the monitor speaker set for demodulated audio. A P25 Handset may also be used for this step if tuned to the proper frequency in conventional P25 mode. 2.1.3.7 Check the Symbol Deviation to verify that it is 1750Hz +/- 75Hz; adjust the TxVcoGain to increase or decrease the deviation if necessary. Also, you may adjust the Frequency Error by trimming the TxVcoOffset if needed.
MASTR III Repeater Calibration Procedure 5/16/2011 • Rx Offset provides a DC reference level adjustment for the receiver audio. This adjustment allows the output reference DC level from the receiver to be matched by the P25netCC Rx input. • RSSI Gain provides level adjustment for the RSSI input. • RSSI Offset provides a DC reference level adjustment for the RSSI input signal. 2.2.1 Equipment Setup Connect the equipment as shown in Figure 2-7.
MASTR III Repeater Calibration Procedure 5/16/2011 2.2.2 Initial Steps 2.2.2.1 Launch PCCT and go to the Configure >Rx and Tx Manual window and set default values for the Rx and RSSI parameters as shown in Figure 2-8. Check the “Enable Editing” boxes for entering parameters. Figure 2-8 Configure Tx and Rx (Manual) Window Raytheon JPS Communications, Inc.
MASTR III Repeater Calibration Procedure 5/16/2011 2.2.3 Rx Calibration 2.2.3.1 Go to the Configure > Rx (Automatic) screen. 2.2.3.2 Set the generator to Analog Duplex Mode at the Receiver frequency; set the modulation for a 1200Hz Sine with 2.83kHz deviation. With the generator on and set to -70dBm, Check the Rx beam box and start the oscilloscope on PCCT. 2.2.3.3 Adjust the Rx Offset so the mean of the observed sine wave is centered as close as possible about zero.
MASTR III Repeater Calibration Procedure 5/16/2011 2.2.3.4 Go to the Configure>Rx (Automatic) window and select trigger on RSSI value of 2000. 2.2.3.5 Hit Trigger, Calculate, and Save to calculate and store the coefficients for Rx Scale Factor and Offset Note: If the Rx gain is too high or low a Calibration Warning will prompt you to change the Rx gain and repeat the operation. 2.2.3.6 Return to the Configure >TX and RX (Manual) screen and place a (-) sign in front of the Rx Scale Factor number.
MASTR III Repeater Calibration Procedure 5/16/2011 2.2.4.2 Set the generator to -120dBm and turn on. 2.2.4.3 With the RSSI Gain set to 10, start the Oscilloscope and adjust the Offset until the trace is around -30,000 (Figure 2-11). Figure 2-11 RSSI Low Level Raytheon JPS Communications, Inc.
MASTR III Repeater Calibration Procedure 5/16/2011 2.2.4.4 Select the “Zeroise” button. Then select the “Get value 1” button next to the -120dBm entry. 2.2.4.5 Change the generator level to -60dBm.Adjust the RSSI gain as required to move the trace to above +30,000. Figure 2-12 RSSI High Level 2.2.4.6 Set the generator back to -120dBm and verify the trace goes back to around -30,000.Adjust RSSI Offset as required. 2.2.4.
MASTR III Repeater Calibration Procedure 5/16/2011 Figure 2-13 RSSI Calculate & Save Screen Raytheon JPS Communications, Inc.
MASTR III Repeater Calibration Procedure 5/16/2011 2.2.5 Rx Verification 2.2.5.1 Turn off test set generator. 2.2.5.2 Reconfigure the test set to generate a STD 1011 test pattern at -70dBm level. 2.2.5.3 Verify the Rx LED on the P25netCC channel is lit. 2.2.5.4 Turn off the generator. 2.3 Bit Error Rate Test 2.3.1.1 On PCCT toolbar select Controller Card\Bit Error rate test. 2.3.1.2 Start the generator with a STD 1011 test pattern at -114dBm.
MASTR III Repeater Calibration Procedure 5/16/2011 Figure 2-15 Load/Save Config Screen 2.4.2 Default Radio Settings Loaded After loading a notification of the action will be displayed (see Figure 2-16 Default Settings Applied Screen). Figure 2-16 Default Settings Applied Screen Raytheon JPS Communications, Inc.
