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7  Temporarily disable the pulse generator. 

8  Using coax cable of minimum convenient length, connect the pulse generator,  

   the RF signal generator, and the radio to the two-way power divider. 

 

9  Disable the noise blanker by placing SW801 to the OFF position. 

 

10 Apply an on -channel signal to obtain12dB SINAD, then increase the RF generator 

   output by 40dB.  

 

11 Enable the pulse generator to produce the 10nsec pulses. Adjust pulse amplitude  

   to return SINAD reading to 12 dB.  

 

12 Switch SW801 to the ON position. The SINAD reading should improve.  

 

13 Reduce the RF generator output until a 12 dB SINAD reading is obta ined. 

 

14 Using a non -metallic tool, slowly tune L801(clockwise or counter-clockwise, as 

   required) for best SINAD.  The amount of L801 adjustment required should be 

   slight. Tune L802 in the same manner. Repeat this step. Noise blanker 

   tuning is complete.       

 

             Table 2-2----Noise Blanker Test Equipment 

  TEST INSTRUMENT              CAPABITIES 

  Pulse Generator                   Pulse Rate: 5000 pulses per second 

                                    Pulse Width: Adjustable to 10 ns at 

                                    1/2 amplitude.  

                                    Output: Continuously variable from  

0.1    to 10V peak into 50 

 

 

  Power Divider,3 port:              50 

 each port, 6 dB attenuation,  

                                                                        D C  to 50 MHz as defined in EIA Standard 

                                                                        R S-204C or RS-204D Appendix A.   

 

 

 

 

Summary of Contents for 70-0671

Page 1: ...o only one side of the speaker and chassis ground Normally voltage measurement will be half of true values 5 Turn the radio on Push on and Push off switch set the VOLUME control to a mid position Conn...

Page 2: ...ODULATOR ALIGNMENT Modulation Limiting 1 Disconnect the hand microphone from its front panel Mic Jack J302 Apply 3Vrms of 1000Hz signal to pin 1 of Mic Jack J302 then initiate transmit 2 Measure total...

Page 3: ...waveform shown in Figure 2 1 11 Change 250 3 Hz CTCSS tone to the transmit test by testing frequency using the programmer Carefully adjust RV401 for 750 Hz 10 Hz w ide or 375 Hz 10 Hz narrow deviatio...

Page 4: ...or L802 unless approp riate test equipment is available for performing the Noise Blanker Tuning steps below Normally these coils are tuned for optimum sensitivity as are L803 and L804 then are retune...

Page 5: ...n The SINAD reading should improve 13 Reduce the RF generator output until a 12 dB SINAD reading is obta ined 14 Using a non metallic tool slowly tune L801 clockwise or counter clockwise as required f...

Page 6: ...h 16 Apply 0 95 uV of modulated standard deviation on channel RF signal to the 50 antenna connector Adjust Squelch range RV201 counter clockwise just until squelch opens audio on Figure 2 2 Adjustment...

Page 7: ...V DC 30 A adjustable voltage 150 W 30 50MHz 50 circuit 50 200 W 30 50 MHz peak responding 5KHz range 30 50 MHz 1 0 ppm accuracy 1 000KHz sine wave 0 4 Vrms output 30 50 MHz range 0 1 1 KuV output 3KHz...

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