Radio Systems with the 8800 Service Monitor by Viavi. This Chapter is intended as an aid to configuring and testing Zetron MT-4E radios using the Viavi 8800. Neither Zetron or Viavi Solutions assume responsibility for damage caused to either unit as a result of misinterpretation or misuse of this procedure.
To upload a file from a USB flash drive, insert the USB flash drive into the USB port and go to Utilities, then File Manager. Copy the Zetron folder from the USB flash drive to the /USER/SaveRecall folder. To recall setups, go to Utilities then Store/Recall, then recall the selected file.
(RF frequency, wide / narrowband, digital / analog, CTCSS / NAC, etc.). Control Cards Some Zetron MT-4E radio systems may have an AC-3E Audio Control Card or CI-BC-4E Base Control Card for use in the radio system. The Control Cards connect to the receiver and transmitter balanced audio lines with an unbalanced load, which could cause some measurements to be in error.
RJ45 cables, rather than turning the front panel switch to the OFF position. All Zetron modules are hot swappable. There is no need to disconnect the power supply when inserting or removing the modules from the subrack.
APPENDIX G: VIAVI 8800 TEST PROCEDURES Audio Connections The Receiver, Transmitter and Auxiliary Balanced audio lines are available for connection on Zetron extender cards or by connecting to the optional back panel A-PNL-AUX96-3 screw-type terminal connector. The extender cards have solder points available on each signal line that can have a small test point (5059- TP110300) that is supplied with the extender card, soldered to them for easy connection with clip-on type clips.
System Voltage Testing The first stage of testing a Zetron MT-4E radio system is to perform a basic system check on the supply and regulated voltages. The System Regulator module is designed with a convenient and easy test point built into the front panel.
1.0 KHz tone is set correctly for your receiver (wide / narrow) in Gen 1. Enter the correct CTCSS tone (if used) and deviation level for the tone in Gen 2. On the Zetron Radio system, ensure the receiver is turned on and turn the System Regulator Speaker switch to ON and INT.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Audio Distortion: To check receiver distortion, inject -70 dBm RF carrier level into the receiver and measure the distortion on the meter as shown in Figure G-6. Figure G-6: Receiver Distortion Measurement Enter the Audio Distortion reading on the MT-4E Test Sheet.
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Enter the Reference Sensitivity (12 dB SINAD) reading on the MT-4E Test Sheet. If the distortion or reference sensitivity measurements are not within Zetron published specifications, the RF Preselector may need re-alignment. Refer to the Receiver RF Preselector Alignment and Tuning section.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Audio Level: The audio level adjustment is not required when connecting the receiver in a repeater configuration using LVDS Serial Data. The audio level adjustment can be done on both the Rx Balanced Audio Output and the Auxiliary Balanced Output (1 and 2).
RF IN on Rx Figure G-10: Receiver Digital Testing On the 8800, load Zetron preset 02 Rx Digital from your internal drive. Enter the correct RF frequency, and ensure that the Pattern is set for 1011. Inject the correct NAC as shown in Figure G-11 and ensure that the receiver is operating. There are no specific measurements to make on this test, just verify that the receiver is operating.
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Enter the Reference Sensitivity (5% BER) reading on the MT-4E Test Sheet. If the BER measurements are not within Zetron published specifi cations, the RF Preselector may need re- alignment. Refer to the Receiver RF Preselector Alignment and Tuning section.
filter (typically 5 - 7 MHz in a VHF or UHF 400 MHz receiver). The UHF 700 / 800 / 900 MHz receiver RF Preselector is Full Band and does not require any tuning. Connect the 8800 and Zetron Radio as shown in Figure G-13. RF Preselector output...
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OPT010. If it is not shown, then the 8800 does not have tracking generator capability. On the 8800, load Zetron preset 03 Rx Preselector Tune from your internal drive. Enter the correct RF frequency as the Center Frequency and ensure the receiver is turned on. The filter waveform should appear as shown in Figure G-15.
APPENDIX G: VIAVI 8800 TEST PROCEDURES Receiver Reference Oscillator Adjustment Connect the 8800 and Zetron Radio as shown in Figure G-16. Computer running RSS Synthesizer L.O. output from Receiver to ANT input on 8800 RECEIVER SYSTEM REGULATOR FUNCTION FREQUENCY (MHz) SQ.
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8800 Figure G-18: UHF 700 / 800 / 900 MHz Receiver Reference Oscillator Connection On the 8800, load Zetron preset 04 Rx Reference from your internal drive as shown in Figure G-19. Figure G-19: Receiver Reference Oscillator Measurement MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS...
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APPENDIX G: VIAVI 8800 TEST PROCEDURES In the receiver RSS, enter the Service section and click on “Ref Oscillator”. The reference oscillator frequency is shown as the “Target Synthesizer RF OUT”. Enter this RF frequency into the frequency on the 8800. The receiver generates this frequency out of the Synthesizer into the 8800.
Figure G-21: Transmitter Analog Testing On the 8800 load Zetron preset 05 Tx Analog from your internal drive. Enter the correct RF frequency on the 8800, set the MIC MODE switch on the front panel of the transmitter to Analog, and flip the other switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS).
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Audio Distortion: The distortion meter will read demodulated audio and give you a transmitter distortion reading as shown in Figure G-22. Figure G-22: Tx Distortion and Power Measurements Enter the Audio Distortion reading on the MT-4E Test Sheet.
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Connect the transmitter to the power amplifier (if used) and measure the RF power output of the amplifier. The Zetron 30 Watt Amplifier’s RF power output can be changed by adjusting the transmitter (exciter) RF power output. Do not exceed power amplifier input levels. Higher power amplifiers typically have a fixed RF power input level and RF power output level.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Deviation Level: The deviation level adjustment is not required when connecting the transmitter in a repeater configuration using LVDS Serial Data. The audio level / deviation level adjustment can be done on both the Tx Balanced Audio Input and the Auxiliary Balanced Input (1 and 2).
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APPENDIX G: VIAVI 8800 TEST PROCEDURES In the Deviation Levels area of the Service section on the RSS, click on the “Key Tx” button and adjust the Tx Balanced Audio Input level adjustment as shown in Figure G-25 until a deviation of +/- 1.5 KHz (narrowband) or +/-3.0 KHz (wideband) is measured on the 8800.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Reference Oscillator Adjustment In the transmitter RSS, enter the Service section and click on “Ref Oscillator”. The reference oscillator frequency is shown as the “Target Frequency”. Enter this RF frequency into the 8800. Click on the “Key Tx” button and the transmitter will generate the reference frequency out of the RF output into the 8800.
Figure G-27: Transmitter CTCSS Testing On the 8800, load Zetron preset 06 Tx CTCSS from your internal drive. Enter the correct RF frequency on the 8800, set the MIC MODE switch on the front panel of the transmitter to Analog and flip the other switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS).
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APPENDIX G: VIAVI 8800 TEST PROCEDURES AF Gen (if used) is configured to inject a 100 Hz tone at -18.0 dBm (0.098 Vrms) into the Tx Subtone input as shown in Figure G-28. If the internal programming is used to generate the CTCSS tone, the AF generator is not used and the CTCSS tone is generated internally in the transmitter.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES In the Subtone Levels area of the Service section on the RSS, click on the “Key Tx” button and adjust the Narrow and/or Wide Internal and/or External Subtone Deviation level adjustment as shown in Figure G-29 until a deviation of +/- 0.35 KHz (narrowband) or +/-0.5 KHz (wideband) is measured on the 8800.
Figure G-30: Transmitter Digital Testing On the 8800, load Zetron preset 07 Tx Digital from your internal drive. Enter the correct RF frequency on the 8800, set the MIC MODE switch on the front panel of the transmitter to Digital and flip the other switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS).
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APPENDIX G: VIAVI 8800 TEST PROCEDURES AF Gen 1 is configured to inject a 1.0 KHz tone at -8.0 dBm (0.308 Vrms) into the transmitter balanced input. A continuous tone injected into the transmitter will be demodulated as a “fluctuating” audio level and tone on older P25 radio systems.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Modulation Fidelity Testing In the transmitter RSS, enter the Service section and click on “Test Patterns”. Ensure the transmitter frequency is in the frequency box. In the Select Pattern window select “C4FM Modulation Fidelity”. Click on the “Key Tx”...
Figure G-33: System Duplex Analog Testing On the 8800, load Zetron preset 08 Duplex Analog from your internal drive as shown in Figure G-34. Enter the correct RF frequency for the receiver and transmitter and ensure that the deviation level of the 1.0 KHz tone is set correctly for your receiver (wide / narrow) in Gen 1.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Ensure that the receiver and transmitter are connected to the repeater controller via the RJ45 cables on the front panel. In some systems, the receiver and transmitter may be connected directly together using the RJ45 cables.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Deviation Level: Check the deviation level. Ideally the deviation level out of the transmitter should match the input to the receiver. The repeater deviation level matching is adjusted by the analog LVDS level adjustment that is available in both the receiver and transmitter (only one needs to be adjusted).
Figure G-36: System Duplex Digital Testing On the 8800, load Zetron preset 09 Duplex Digital from your internal drive as shown in Figure G-37. Enter the correct RF frequencies for the receiver and transmitter, and select the Generators - Modulation screen and ensure that the Pattern is set for 1011 and inject the correct NAC for the receiver.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES Ensure that the receiver and transmitter are connected to the repeater controller via the RJ45 cables on the front panel. In some systems, the receiver and transmitter may be connected directly together using the RJ45 cables.
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APPENDIX G: VIAVI 8800 TEST PROCEDURES This Page Intentionally Left Blank. MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS...
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