SGC_SG-2020_align.pdf

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1、“No Compromise Communications” SG-2020 Transceiver Test/Calibration Procedure SG-2020 TEST DOCUMENT This SG-2020 Test Document is divided into two sections: Section One: Basic & Simple Test Section Two: Full Test & Calibration This test document is provided to SGC dealers, techni- cians and engineer

2、s who have full knowledge and experi- ence with electronics and HF radio communications. The tests and calibration described must be performed using appropriate, calibrated, good quality instruments. Note that Section Two is not covered under the Warranty of the SG-2020. Any information concerning t

3、his docu- ment must be executed in writing only. These procedures are provided as informational only to assist qualified tech- nicians or engineers with field use and service of the SG- 2020 transceiver. SG-2020 BASIC PERFORMANCE TESTS The SGC factory test procedures as well as the test procedures d

4、etailed in the ARRL Handbook chapter 26 can be used to fully measure the performance of the radio. The following are simple tests which do not require laboratory test equipment and can be used to determine if the unit is generally operating properly. 1. Receiver Sensitivity: The measurement of sensi

5、tivity with signal levels below one micro volt requires a well shielded signal generator due to the very low level signal involved. Inexpensive generators of the sort used by amateurs or for service work leak signals which causes inaccurate readings at low signal levels. By using a larger signal lev

6、el and verifying the expected AGC response, a reasonable sensitivity check can be obtained with an inexpensive signal generator. a. Set the SG-2020 to the desired frequency with mode USB and BW 2.2 KHz. Be sure to turn the RF gain fully clockwise. b. Set the signal generator to the same frequency pl

7、us 1 KHz and set its output level to 50 micro volts. c. Verify that the 5 LEDs in the bargraph display are lit. If the bargraph reads more than 2 LEDs below the expected value, the unit requires service. 2. Transmit Quality: Listen to the voice quality on another receiver being careful to avoid over

8、- load. Most defects can be heard with critical listening tests. A quantitative measurement of linearity requires a two-tone audio generator with the results normally viewed on a spectrum analyzer. However, with care it is possible to use an attenuator and receiver in place of the spectrum analyzer.

9、 3. Transmit Power: The transmitter is connected to a power meter and dummy load. The mea- sured power is compared to the power setting of the SG-2020. Note that the power meters usually sold for amateur use are not very accu- rate. A calibrated Bird or similar meter is needed for reliable results.

10、SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fax: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 2 2001 SGC Inc 4. SWR Shutdown: Transmit 20 watts in CW mode with no antenna connected. You should get less than 5 LEDs on for f

11、orward power and full scale reading (all LEDs on) for reverse power. as indicated by the bargraph display. 2001 SGC IncSGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fax: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 3 SGC TES

12、T DESCRIPTION NOTE: Any adjustments made to the SG-2020, besides the R46 CW sidetone adjustment are NOT covered by the warranty. The following are tests performed on a fully assembled SG-2020 transceiver. TEST EQUIPMENT REQUIRED Audio Signal Generator (Audio out applied to the microphone connector o

13、f SG-2020 under test) RF Noise Generator RF Sinusoidal Signal Generator RF Spectrum Analyzer in addition to a RF Sweep Generator (Connected through an attenuator of min. 35 dB to the dummy load output.) Oscilloscope Tektronix 465B or equivalent Current meter 0-1 Amp Range Current meter 0-10 Amp Rang

14、e Voltmeter Fluke 77 or equivalent Power Supply PS-10 or equivalent 10-amp power supply Frequency Counter (connected to the vertical output of oscilloscope.) Audio Distortion Analyzer (connected at the speaker/headphone jack) 1.0 L.O. PLL ERROR VOLTAGE 1.1 Connect voltmeter to TP3 and GND on the Exc

15、iter PCB. 1.2Dial 29700.0 KHz on the display. 1.3 Verify voltage reading is less than 16 VDC. If not, adjust the spacing between the windings on L18. Pull the windings together for a lower-voltage reading or spread windings for a higher-voltage reading. 1.4 Change the frequency to 1800.0 KHz. 1.5 Ve

16、rify new voltage reading is approximately 3 VDC. 2.0 ALIGN RECEIVE IF TRANSFORMERS 2.1Connect signal generator to antenna input. 2.2Connect voltmeter to AGC TP13 and GND on the Exciter PCB. 2.3Set display frequency to 14150.0 KHz USB, signal generator to receiver frequency +1 KHz and adjust output l

17、evel of signal generator (typical- ly 10 V) for 5 VDC reading on the voltmeter. 2.4Adjust T3 and T4 for maximum AGC voltage, while reducing signal generator output as necessary to keep AGC voltage near 5 VDC. SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fax:

18、 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 4 2001 SGC Inc Bird Wattmeter model 43 or equivalent. 3.0 LPA BIAS This is not a routine procedure and should be done only when the final transistors are replaced. 3.1 Set display for 14150.0 KHz, USB. 3.2Connect voltme

19、ter across bias test points TP1 and TP2 on LPA (across R29, LPA page 3/3), key the SG-2020 (with no RF input), and verify that the meter reads 7 mV. Readjust R7 on LPA if necessary. 4.0 ADJUST REVERSE DETECT VOLTAGE 4.2 Connect audio generator to microphone input. Set for 1300 Hz 15 mV output. 4.3 C

20、onnect voltmeter set on millivolt scale to TP5 (REV) and GND on the LPA. 4.4 Set power to P20 by pressing CMD + NB then adjust spinner to 20. Press MEM. 4.5 Key PTT and verify 20 watts output power. Readjust the audio genera- tor below the ALC level kick-in (or until 20 watts reads on wattmeter). 4.

21、6 Adjust C56 on LPA for min. voltage on TP5 (less than 50 millivolts) 5.0 RADIO CALIBRATION 5.1 Set the radio to 3,700.0 KHz, USB. 5.2Turn off power. 5.3 Turn power back on and immediately press and hold CMD until C appears on display. 5.4 Release CMD button and then immediately (before function tim

22、e-out occurs) press BW button - “CA” should be shown on display. 5.5 Immediately press LIGHT button - “CAL” should be displayed. You are now in calibration mode and the number 1 (one) should appear on left side of display along with a reference reading on the right side. Identify calibration data fo

23、r the exciter in the radio 5.6 You will need the data results from the test N920ExcFilterSweep (Exciter filter sweep). Calibration 5.7 The radio should be warmed up for at least 20 minutes to allow everything to stabilize. Connect oscilloscope probe to the indi- cated REF. point in paragraph 5.9 and

24、 adjust tuning knob until desired frequency is displayed on the frequency counter (connected with the scope). Observe and record reading on LCD display and press MEM to store this reading. 2001 SGC IncSGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fax: 425-746

25、-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 5 4.1 Set the display for 14150.0 KHz USB. 5.8 Continue on through step A Ref. PointStepAdj. Tuning Knob for: VCXO ADJ.USBLO TP5161,656.269 KHz LSB261,666.294 KHz CW361,663.157 KHz 5.8.1 Adjust display for 3200. 5.8.2 Adjust C1

26、46 for maximum amplitude on scope at TP6. 5.8.3 Adjust T6 for maximum amplitude. 5.8.4 Readjust C146 until the frequency counter is within 100 Hz of the BFO crystal sort value. BFO ADJ. USB BFO TP6 5 See page 12 LSB6See page 12 CW7See page 12 LO ADJ.USBLO TP58See page 12 LSB9See page 12 CWASee page

27、12 LED Test 5.9 After completion of step A, press MEM and the display should step through the LED cycle test. Check that all LEDs are functional, and that no LED is tied to another. Display Calibration 5.10 Connect frequency counter to audio output (J7 at rear of radio) 5.11 Place radio at these set

28、tings: A. Display to 1.850 MHz B. Mode to USB C. BW to 2.7 KHz 5.12 Inject a 1.851-MHz, 3-uV signal and observe that the frequency counter reads 1,000Hz +/- 10Hz. Adjust the spinner knob if necessary to achieve SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fa

29、x: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 6 2001 SGC Inc 1,000Hz +/- 10Hz. Note: Skip step 5.13 if adjustment is not necessary. 5.13 Press CMD + XCVE and verify that the XCVE, RIT, and SPLIT LEDs light. Adjust spinner until display reads 1.850 MHz. Press MEM.

30、 5.14 Change the mode to LSB and the signal generator to. 1.849 MHz. 5.15 Verify that the frequency counter reads 1,000 Hz plus or minus 100Hz. 5.16 Set all 20 default channels to factory preset frequencies. See page 20 of th SG-2020 Operations manual, Version 2.01. 6.0 TRANSMIT SSB BALANCE (USB vs

31、LSB) CHECK 6.1 Set display for 1850.0 KHz, USB and key microphone. 6.2Increase level of audio generator applied at the microphone jack (1.3 KHz, sinusoidal) until output power reads 10 watts. 6.3Unkey mic, change to LSB and rekey mic. Power output in LSB must be within 5 watts of USB. 6.4Set whichev

32、er SSB is higher to 10 W, and check that the other SSB is 5W or greater . 6.5Repeat the above steps for frequencies: 3700.0, 7140.0, 14150.0, 18150.0, 29700.0 KHz then verify that USB/LSB difference is less than 5W. Carrier Level Check( TX 20W, USB, BW=2.7, 1.3 KHz at microphone) 6.6 Set radio to 18

33、50.0 KHz, USB. 6.7Connect 1300 Hz audio signal to mic input. 6.8Key radio and adjust output level of audio generator until radio is trans- mitting 20 watts. 6.9Adjust frequency knob on the spectrum analyzer until the signal trans- mitted is displayed. Read the dB level of this signal. 6.10 Remove th

34、e signal from the microphone and check that the carrier level decreases to at least 40 dB below the dB level of the applied signal. 7.0 Power - Meter LEDs This test checks that the power meter indicates properly for FWD and REV power readings. NOTE: Precise calibration is not supported. Forward powe

35、r 7.1Set radio to 14150.0 KHz, USB, BW=2.7, connect audio input to micro- phone connector and key mic box. 7.2Increase audio input (1.3 KHz) while observing the LEDs and watt meter. 7.3 At approximately 14W - all 5 green LEDs should light. 7.4 At approximately 20W - all 5 green and 2 red LEDs should

36、 light. 7.5At approximately 25W - all 10 LEDs should light 2001 SGC IncSGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fax: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 7 Reverse Power 7.6Depress REV while transmitting 20W int

37、o a dummy load and verify that 2 LEDs light. 7.7Depress REV while transmitting 20 W without any antenna or dummy load connected and verify that all 10 LEDs light. (NOTE: Do not transmit for more than 5 sec. Watch the current meter, it should be reduced to less than 2 Amps by the ALC/REV protection c

38、ir- cuitry) 8.0 POWER CALIBRATION TEST This test will check/readjust the radio for max. 20W RF OUT . 8.1 Set P for 20 watts after setting the frequency to 14150.0 KHz. 8.2 Set power to M (maximum) 8.3 Attach the radio to a 50-ohm dummy load. 8.4 Key mic and increase audio input level (1.3 KHz, and n

39、ot more than 20 mV) until maximum power is achieved (just below the saturation level.) 8.5 Press (CMD + NB) and adjust RF out to 20W on watt meter. Read the P value on the display and press MEM button. Load P Value in all 20 channels 8.6 Go to Channel 1 frequency, press (CMD+NB) and adjust knob for

40、the new power setting P(from above) and then press MEM to store this P value temporarily (for as long you are in this channel). Press (FAST+MEM) together for storing permanently this value in this channels memory. 8.7 Repeat the above step for the remaining 19 channels/frequencies. 9.0 TRANSMITTER R

41、ESPONSE (into a 50 ohm dummy load) NOTE: Power response and spurs readings can be taken at the same time. Power response (Avoid continuous TX for more than 10 sec.) 9.1Set display for 1800.0 KHz, USB and key in transmit. 9.2Increase audio generator level until maximum power is achieved while staying

42、 within the limits of ALC, current, and voltage values indicated on the table on the following page. 9.3Repeat the above steps for all frequencies in the table on the following page, and measure input drive, input DC voltage, ALC voltage and output power and compare these readings with the values an

43、d limits set. SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009 Fax: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 8 2001 SGC Inc 2001 SGC IncSGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA P.O.Box 3526, 98009

44、Fax: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331 E-mail: Web site: 9 Spurious transmissions check( 20W USB) 9.4 While doing the power response test (above), compare any spurs trans- mitted with the peak power signal. There should be none higher than - 40 dB. 9.5Repeat the above ste

45、ps for all the frequencies listed on the following table. FREQ. MHzVDCAmpALC VDCW PEPAF mV 1.8012 - 18max. 4.53 - 5= 18max. 20 3.7012 - 18max. 4.53 - 5= 19max. 20 7.1412 - 18max. 4.53 - 5= 19max. 20 14.1512 - 18max. 4.53 - 5= 19max. 20 18.1512 - 18max. 4.53 - 5= 19max. 20 29.7012 - 18max. 4.53 - 5=

46、14max. 20 10.0 TRANSMIT QUALITY TEST This will test for good quality of voice transmitted into a dummy load, and received in a close-by radio set on the same frequency and mode. 10.1 Use a known good microphone and transmit a few phrases of test signal to a near-by radio set on the same frequency. 1

47、0.2 Listen to the quality of the voice in the other radio while monitoring modulation on the scope attached at the output of your radios dummy load. 11.0 RECEIVER CURRENT TEST 11.1 Connect RF Generator at the antenna connector, and an ammeter in series with the radio. 11.2 Radio settings - 14150.0 K

48、Hz USB, AF max., RF max., BW 2.7 KHz. 11.3 Measure current readings on the ammeter for each of the situations: BackliteONOFF Standby 450 mA 380 mANo RF Input Max. Signal 900 mA1 V Antenna Input Idle 100.2 - 0.3 3.70 100.3 - 0.5 7.14 100.4 - 0.6 14.15 100.5 - 0.7 21.35 100.5 - 0.7 29.70 100.5 - 0.7 D

49、ecibel level 12.5 Change the audio analyzer function switch to distortion position, meter range to -10 to -20 position, and adjust switch sensitivity to give mid- scale reading. 12.6 Adjust vernier control for 0 dB, switch RF output of signal generator off, and check for minimum of 10 dB drop, as expected on the table above. 12.7 Repeat the above tests for USB & LSB in all frequencies listed above, and verify your readings against the listed reference values (USB = LSB 2 dB). 13.0 RECEIVER AGC TEST 13.1 Set radio to 14150.