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Audio feedback problem

Discussion in 'General Electronics Chat' started by Space Varmint, Oct 16, 2008.

  1. Mikebits

    Mikebits Well-Known Member

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    Darn my upload of an xls file did not work. Let's try a zip version.
     

    Attached Files:

  2. transistor495

    transistor495 Member Forum Supporter

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    I hope atleast it will not create ducks :D

    Well, I have a query(1min SV ;)) that RFC coil ends to be soldered on to the ends of carbon resistor making them parallel??
     
  3. Mikebits

    Mikebits Well-Known Member

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    They are parallel, but usually the resistor value is so high that its impedance can be ignored. Winding around a resistor is just a convenient way to make a coil. You can ignore the resistor.
     
  4. dave

    Dave New Member

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  5. Space Varmint

    Space Varmint New Member

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    Caught the Woodpecker while tuning around:http://www.mediafire.com/file/kkmmdafymlm/Woodpecker.wma
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Again I heard some ducks quacking.
    The audio quality is horrible.

    Is the BFO at the wrong frequency or are the guys castrated sopranos?
    Why is the audio bandwidth so narrow?
     
  7. Space Varmint

    Space Varmint New Member

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    Which one? In the whole design I'm using only two types of cores except for the BFO. I'm using Amidon FT-37-43 for the chokes and the filters & oscillators are Amidon T-37-02. The BFO needed to run at the 2nd IF which is around 2MHz (low freq) so I'm using Amidon T-80-06 (yellow).

    I would not use a resistor. It will work in very low signal levels but the ferrite cores (FT-37-43) have self shielding properties. It enables you to get away with less shielding.
     
  8. kchriste

    kchriste New Member Forum Supporter

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    That's not the woodpecker. If it is, there is something seriously wrong with your receiver. The woodpecker has a much slower repetition rate. The SSB audio sounds normal though.
     
  9. Space Varmint

    Space Varmint New Member

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    Thanks kchriste. Well I sure thout that was the woodpecker. Seems like the same one I've been hearing for years but who knows. Might be the HAARP. It uses similar technology.
     

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