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Re: [softrock40] Re: UK residents only

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  • Loftur J√≥nasson
    ... You may want to consider replacing the 0.1uF caps on the opamp outputs to 1uF. The raising of the noise floor you are most likely seeing in the low kHz
    Message 1 of 5 , Apr 1 7:37 AM
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      >>
      > Below 300Hz thay maybe non linear! above 300HZ you maybe ok but I tried two
      > tx's out of old modems and they were both non linear causing the noise floor
      > to go up and down across the spectrum in the SDR software. Good luck Steve
      > 2E0ZEH
      >
      You may want to consider replacing the 0.1uF caps on the opamp outputs
      to 1uF. The raising of the noise floor you are most likely seeing in
      the low kHz range is due to ringing, resonance between the 0.1uF
      output capacitors and the inductance in the transformer. You may also
      be seeing a big dip below 1kHz. Larger caps, for instance 1uF, will
      rectify both.

      73 de Loftur, ve/tf3lj
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