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Appendix H: Viavi CX300 Tests 

MAINTENANCE GUIDE |   MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS

Receiver RF Preselector Alignment and Tuning

Tuning of the RF Preselector filter is typically only required when the Analog or Digital Sensitivity or Analog 

Distortion do not meet published specifications, or when the receiver RF frequency is changed beyond the 

band pass of the 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 CX300 and Zetron Radio as shown in Figure H-10.

Figure H-10: Receiver RF Preselector Tuning

The RF Preselector output is a small RF cable internal in the receiver that terminates in an SMB connector.  

The SMB plugs into J3 on the Receiver Mainboard. Disconnect the SMB cable from J3 and use the SMB-BNC 

adapter to connect this point to the RF INPUTon the CX300 as shown in Figure H-11.

Figure H-11: Receiver RF Preselector Connection

RF Preselector output

from Receiver to

RF INPUT on CX300

RECEIVER

SQ. DISABLE

OFF

NORM

BUS

CNTL

A D

RF I N

IN

REF

USB

FREQUENCY (MHz)

MADE IN CANADA

MODEL # CODE

VOL

SYSTEM REGULATOR

METER

+

-

MADE IN CANADA

ON
OFF

SPKR

INT

EXT

EXT

SPKR

OFF

POWER

ON

2

1

5

4

3

6

7

8

11

10

9

FUNCTION

12

RF OUTPUT from

CX300 to RF IN on Rx

J3

on CX300

To RF INPUT

RF Preselector 

output

Summary of Contents for Viavi CX300

Page 1: ...i Appendix H Viavi CX300 Tests MAINTENANCE GUIDE MT 4E ANALOG P25 DIGITAL RADIO SYSTEMS Appendix H Viavi CX300 Tests MAINTENANCE GUIDE www zetron com...

Page 2: ...n MT 4E Radio System Test Sheet 03 Turning OFF the MT 4E Receiver and Transmitter Modules 04 Audio Connections 05 SYSTEM REGULATOR TESTING 06 System Voltage Testing 06 RECEIVER TESTING 07 Receiver Ana...

Page 3: ...esult of misinterpretation or misuse of this procedure Zetron manufactured products are warranted against defective materials and workmanship This warranty does not extend to damage due to misuse negl...

Page 4: ...he USB ash drive into one of the USB ports and select the Home button then Files Copy the Zetron folder from the USB ash drive to the Disk CX300 Internal folder To recall setups while in the CX300 Com...

Page 5: ...Card remove the control card from the rack for the individual receiver and transmitter tests unless otherwise noted Adapters Cables and Extender Cards Various adapters cables and extender cards are re...

Page 6: ...hen the MT 4E receiver and transmitter channel and bank select lines are connected together in parallel turning the MT 4E receiver or transmitter front panel switch to the OFF position will cause the...

Page 7: ...h clip on type clips Recommended Test Points are Audio Control Card and Base Control Card Extender Card pins EC 96D1 and EC 96K 1 22 Auxiliary 1 Audio Output B11 and A11 Auxiliary 2 Audio Output C1 an...

Page 8: ...c d c a c d c a c d c a c d c a c d c a c d c a F F mA S nS n A A mA mA mV mV V V mV mV V V OFF OFF C C A A A A AA M O C M O C VV TEMPERATURE TEMPERATURE A mA m AA AutoHOLD LOGGING SAVE FAST MN MX SE...

Page 9: ...tion level for the tone in M2 On the Zetron Radio system ensure the receiver is turned on and turn the System Regulator Speaker switch to ON and INT Set the FUNCTION rotary switch to position 3 for Rx...

Page 10: ...Figure H 4 Receiver Distortion Measurement 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 H 4...

Page 11: ...r reference sensitivity measurements are not within Zetron published speci cations the RF Preselector may need re alignment Refer to the Receiver RF Preselector Alignment and Tuning section Squelch Ad...

Page 12: ...ohms is measured on the AF Level meter of the CX300 as shown in Figure H 4 Figure H 6 RSS Receiver Audio Level Adjustment To adjust the auxiliary balanced audio output plug the AC 3E Control Card or...

Page 13: ...the 1011 test pattern Inject the correct NAC as shown in Figure H 8 and ensure that the receiver is operating There are no speci c measurements to make on this test just verify that the receiver is o...

Page 14: ...8 Click on the Start Test button to start the BER test You should get 0 BER at the 70 dBm default RF carrier level Monitor the BER reading while slowly reducing the RF carrier level as shown in Figure...

Page 15: ...n in Figure H 10 Figure H 10 Receiver RF Preselector Tuning The RF Preselector output is a small RF cable internal in the receiver that terminates in an SMB connector The SMB plugs into J3 on the Rece...

Page 16: ...e correct RF frequency as the Center Freq and ensure the receiver is turned on The lter waveform should appear as shown in Figure H 12 Figure H 12 Receiver RF Preselector To tune the RF Preselector lt...

Page 17: ...s mounted on the Synthesizer beneath the RF Preselector The SMB BNC adapter is required to connect this point to the RF INPUT on the CX300 as shown in Figures H 14 VHF and UHF 400 MHz Receiver and H 1...

Page 18: ...MS Figure H 15 UHF 700 800 900 MHz Receiver Reference Oscillator Connection On the CX300 load Zetron preset 04 Rx Reference from your internal drive as shown in Figure H 16 Figure H 16 Receiver Refere...

Page 19: ...r RF OUT Enter this RF frequency into the frequency on the CX300 The receiver generates this frequency out of the Synthesizer into the CX300 Monitor the RF Error on the CX300 To change the reference f...

Page 20: ...g and ip the other switch to KEY TX or set the switch to NORM and key the transmitter through the RSS The AF Generator A1 is con gured to inject a 1 0 KHz tone at 8 0 dBm 0 308 Vrms into the transmitt...

Page 21: ...SYSTEMS Audio Distortion The distortion meter will read demodulated audio and give you a transmitter distortion reading as shown in Figure H 19 The high limit is set to 3 0 Figure H 19 Tx Distortion a...

Page 22: ...r output will vary slightly with the 10 17 Vdc input Figure H 20 RSS Transmitter Power Level Adjustment Enter the RF Power Output reading on the MT 4E Test Sheet Connect the transmitter to the power a...

Page 23: ...rd or CI BC 4E Base Control Card Change the Audio Filter near the top left corner from 0 3 3 4 KHz BP to 15KHz LP as shown in Figure H 21 for a more accurate deviation reading without CTCSS encode If...

Page 24: ...d The MT 4E Transmitter will transmit a maximum deviation at an audio frequency of approximately 1300 Hz Enter the Transmitter Maximum Deviation Level reading on the MT 4E Test Sheet To adjust the aux...

Page 25: ...Key Tx button and the transmitter will generate the reference frequency out of the RF output into the CX300 Monitor the RF Error on the CX300 To change the reference frequency adjust the softpot slid...

Page 26: ...from the CX300 Figure H 24 Transmitter CTCSS Testing On the CX300 load Zetron preset 06 Tx CTCSS from your internal drive Enter the correct RF frequency on the CX300 set the MIC MODE switch on the fro...

Page 27: ...gured to inject a 100 Hz tone at 18 0 dBm 0 098 Vrms into the Tx Subtone input as shown in Figure H 25 If the internal programming is used to generate the CTCSS tone the AF generator is not used and...

Page 28: ...on and adjust the Narrow and or Wide Internal and or External Subtone Deviation level adjustment as shown in Figure H 26 until a deviation of 0 35 KHz narrowband or 0 5 KHz wideband is measured on the...

Page 29: ...IC MODE switch on the front panel of the transmitter to Digital and ip the other switch to KEY TX or set the switch to NORM and key the transmitter through the RSS Computer running RSS Tx Balanced Aud...

Page 30: ...nto the transmitter balanced input however the CX300 does not demodulate the P25 signal Ensure the correct NAC is being transmitted properly as shown in Figure H 28 The NAC is programmed into the tran...

Page 31: ...n as shown in Figure H 29 and the transmitter will begin generating the test pattern out the RF output Figure H 29 RSS Transmitter Modulation Fidelity Test Pattern Measure the Modulation Fidelity of t...

Page 32: ...ansmitter front panel switch to NORM The MIC MODE switch on the transmitter front panel can be set to either Digital or Analog this test does not make use of the front panel switch TRANSMITTER BUS CNT...

Page 33: ...sing the RJ45 cables Figure H 32 System Analog Duplex Measurement Distortion The distortion meter will read demodulated audio and give you a complete repeater system distortion reading The high limit...

Page 34: ...djusted In the receiver or transmitter RSS enter the Service section and click on LVDS Level A default value of 100 on the softpot slider should be close to matching receiver and transmitter deviation...

Page 35: ...tch on the transmitter front panel can be set to either Digital or Analog this test does not make use of the front panel switch TRANSMITTER BUS CNTL MIC RF OUT A D DIGITAL OFF NORM KEY ANALOG TX MICMO...

Page 36: ...l In some systems the receiver and transmitter may be connected directly together using the RJ45 cables Figure H 35 System Digital Duplex Check There are no speci c measurements to make on this test j...

Page 37: ...35 Appendix H Viavi CX300 Tests MAINTENANCE GUIDE MT 4E ANALOG P25 DIGITAL RADIO SYSTEMS This Page Intentionally Left Blank...

Page 38: ...ist for option pricing Specifications subject to change without notice ZETRON EMEA 27 29 Campbell Court Bramley Hampshire RG26 5EG United Kingdom P 44 1256 880663 F 44 1256 880491 E uk zetron com ZETR...

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