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Receive signals are a bit 'chirpy'

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  • g4abx
    Hoping someone can help? The Sierra seems to be working fine--ish! In order to get the BFO setting to give a sensible RX note with the passband of the ABX, the
    Message 1 of 1 , Aug 10, 2010
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      Hoping someone can help?
      The Sierra seems to be working fine--ish!
      In order to get the BFO setting to give a sensible RX note with the passband of the ABX, the trimmer cap (C16?) has to be adjusted to one of its extremities. Having done this (and it appears rather 'touchy') chirp has appeared on received signals -- indicating to me that the Oscillator is not going very 'strongly.' If I adjust the trimmer to a point where the received pitch is 'high' and completely hopeless in terms of matching the TX sidetone note, then the RX chirp appears to have gone, indicating to me that whatever is causing it (AGC pulling the BFO maybe?) is not having an adverse affect.
      It appears that the trimmer isn't large enough in capacity terms (I'm assuming the extremity is the fully 'meshed' condition)
      Any suggestions? (And yes, the PSU is fine, nice & clean, and the TX note sounds excellent)
      Many thanks
      Bruce G4ABX

      By the way, my first QSO on 40M (the only module I've built so far) was 2500 miles -- Oh yes and nice to have such a cute adjustable filter named after me :-)
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