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Re: [softrock40] Re: Signal at osc freq

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  • Bill Dumke
    Steve, That is caused by the limitations in the bandwidth of the sound card at the low frequency end and AC ground loops. Usually it can be eliminated if you
    Message 1 of 3 , Sep 25, 2007
      Steve,

      That is caused by the limitations in the bandwidth of the sound card at
      the low frequency end and AC ground loops. Usually it can be eliminated
      if you get a good sound card like a Delta 44 and get rid of all the AC
      ground loops. I use an RF isolation transformer on the antenna
      connection (that was my biggest ground loop problem), and I cut the
      ground for the PTT cable at the RXTX. I don't have any peak like you
      are seeing now. In fact, I see a very minor dip at the center frequency
      on 40 meters.

      Bill wa9pwr

      snhou99 wrote:
      > I replaced the audio cable going from the radio to the soundcard.
      > Does this look like it should with no antenna at the center frequency?
      > http://www.n5en.com/SoftRockOscFreq3.jpg
      >
      > Steve
      >
      >
      > --- In softrock40@yahoogroups.com, Steve Niles <N5EN@...> wrote:
      >
      >> I purchased a compatible sound card (SB Extigy) and my 20m SoftRock
      >>
      > Lite
      >
      >> is now working.
      >>
      >> Newbie question...
      >>
      >> I was tuning around and found this continuous signal at the
      >>
      > receiver's
      >
      >> oscillator frequency (18.724734 / 4 * 3).
      >> http://www.n5en.com/SoftRockOscFreq.jpg
      >> http://www.n5en.com/SoftRockOscFreq2.jpg
      >>
      >> It is also present with the antenna disconnected.
      >>
      >> Would the receiver design cause this or is something out of
      >>
      > alignment?
      >
      >> Steve N5EN
      >>
      >>
      >
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
      >
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