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Message |
    
Doggie619
Junior Member
Username: Doggie619
Post Number: 30
Registered: 2-2005
| | Posted on Monday, September 26, 2005 - 4:00 pm: | 
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How do you adjust the ears on the 2985DX. I cant hear some distant units i used to hear before. |
Tech808
Moderator
Username: Tech808
Post Number: 7415
Registered: 8-2002
| | Posted on Monday, September 26, 2005 - 6:27 pm: |
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Doogie619,
Have you Checked your Coax and Antenna for problems?
Have you also considered the Sunspot Cycle that we are in now will also effect the distant stations that you will be able to hear?
SUNSPOT CYCLE REPORT
or if you have the Equipment here is the Receiver Alignment for your radio.
Equipment required for Alignment procedure:
• DC Power Supply ( 13.8 Vdc, 20A )
• Oscilloscope (50 MHz), with X10 probe
• 50 W dummy load
• Frequency Counter - 0 to 30 MHz
• Digital voltmeter or Multimeter.
• Audio Generator
• FM Signal Generator
• SINAD Meter
• RF Wattmetter ( 25~60 MHz, 100W )
1. Receiver Setup: Put the mode selector on AM, the RF gain fully clockwise (maximum gain), squelch to minimum (unsquelched), volume at 2 o'clock, CH 20, and NB/ANL to OFF. Connect an RF carrier frequency of 28.295 MHz, AM modulated with a 1 KHz audio tone at 30% modulation level.
2. AM Sensitivity:
Connect a SINAD meter to the external speaker jack.
Adjust L3, L4, L6, L7, L8, L10, L11 and L12 for best SINAD.
Increase the RF generator to 1mV RF carrier level.
Adjust L3, and L4 for minimum distortion.
Verify that the receiver AM sensitivity is better than 0.5µV for 10 db SINAD.
3. FM Distortion:
Change the RF generator to the FM mode, 1mV RF carrier level, FM modulated with a 1 KHz audio tone ± 3 KHz modulation level.
Adjust L5 for minimum distortion.
4. USB Sensitivity:
Turn off the audio modulation of the RF generator, and change it's frequency to 28.296 at an RF carrier level of 1mV. Set radio to USB RX mode.
Adjust L13 and L14 for maximum audio output ( must be greater than 3V).
5. LSB Sensitivity:
Keep the audio modulation of the RF generator off, change frequency to 28.294 at an RF carrier level of 1mV, set radio to LSB mode.
Adjust L13, and L14 for maximum audio output (must be greater then 3V).
6. NB Adjust:
Set radio to CH 21 AM RX mode, NB-ANL/OFF switch to ON, adjust RF generator to 28.305 MHz with an RF carrier level of 1mV, AM modulated with a 1 KHz audio signal at 30% modulation. Connect a digital voltmeter to TP1 (R11).
Adjust L1 and L2 for DC Voltage to max ( 1.3V ).
7. AM Scale Meter:
Turn NB-ANL switch to OFF, SWR/S/RF switch to S/RF position, set radio to CH 40 AM RX mode, RF signal generator setting 28.495 MHz with a carrier level of 100 µV, AM modulated with a 1KHz audio signal at 30%.
Adjust VR1 so that meter needle goes to S9 on the S scale.
8. USB Scale Meter:
SWR/S/RF switch to S/RF position, set radio to CH 40 USB RX mode, RF signal generator setting 28.496 MHz with a carrier level of 100 µV, no audio modulation.
Adjust VR2 so that meter needle goes to S9 on the S scale.
9. AM Squelch:
Set radio to CH 40 AM RX mode, SQ control fully clockwise, RF signal generator setting to 28.495 MHz , RF carrier level at 1 mV, AM modulated with a 1 KHz audio signal at 30%.
Adjust VR4 very slowly until squelch noise just goes off.
10. SSB Squelch:
Set radio to CH 40 USB RX mode, SQ control fully clockwise, RF signal generator setting to 28.496 MHz , RF carrier level at 1 mV, with audio modulation.
Adjust VR3 very slowly until squelch just goes off.}
Hope this helps,
Lon
Tech808
CEF808
N9OSN |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1555
Registered: 7-2004
| | Posted on Monday, September 26, 2005 - 8:13 pm: |
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