Loading ...
Sorry, an error occurred while loading the content.

Re: Big signal at 0 Hz even with SR40 is off

Expand Messages
  • John
    I am playing with mine also. Maybe those of us with Cheap sound cards fine this, I do. Two things: If just a single frec it is most likely the math finding a
    Message 1 of 21 , Oct 1, 2006
    • 0 Attachment

      I am playing with mine also.

      Maybe those of us with “Cheap” sound cards fine this, I do.

       

      Two things:

        If just a single frec it is most likely the math finding a 0 hrz tone.

        If two peaks close together it may be 60 hz pickup in the audio cord.&nbs

      (Message over 64 KB, truncated)

    • Cecil Bayona
      ... The picture of the single stand alone spike is what one of PC s has, the other four have the typical spike with noise going out quite a ways slowly and
      Message 2 of 21 , Oct 1, 2006
      • 0 Attachment
        Alberto I2PHD wrote:
        > Marco IK1ODO wrote:
        >> There would be also a peak at 0Hz due to DC
        >> imbalance of the ADC inputs, but the ADCs used in
        >> 24bit souncards have an internal high pass filter
        >> cutting under 1 or 2Hz, suppressing that.
        >>
        > Marco is quite right, as demonstrated by these two screen captures. The
        > first is the digitizing process carried on by Adobe Audition, using the
        > onboard AC'97 chipset, with the card input left open. As you can easily
        > see, there is a substantial DC offset produced by the ADC.
        >
        >
        >
        > The same chipset produced this strong zero frequency peak, entirely
        > caused by the DC offset :
        >
        >
        > 73 Alberto I2PHD
        >
        >
        The picture of the single stand alone spike is what one of PC's has, the
        other four have the typical spike with noise going out quite a ways
        slowly and meeting the noise floor about 2-3 KHz away.

        On most PC's that is a rare item most people don't have that kind of
        response.

        --

        Cecil
        KD5NWA
        www.qrpradio.com www.hpsdr.com

        "Sacred Cows make the best Hamburger!" Don Seglio Batuna
      • n3hkn
        Spread Spectrum... CPU=AMD 2600 ECS is motherboadr mfg. KT-600 Dick N3HKN It is about 2 years old--- In softrock40@yahoogroups.com, Sam Morgan ... PC ...
        Message 3 of 21 , Oct 2, 2006
        • 0 Attachment
          Spread Spectrum...

          CPU=AMD 2600
          ECS is motherboadr mfg. KT-600

          Dick N3HKN


          It is about 2 years old--- In softrock40@yahoogroups.com, Sam Morgan
          <ka5oai@...> wrote:
          >
          > n3hkn wrote:
          > > I switched off the spread pectrum BIOS option in my "home made"
          PC
          > > and the width of the noise spike is now vey narrow. Looks like
          almost
          > > a single frequency carrier.
          > >
          > just curious, how new is your motherboard? I guess if u told me
          what cpu it's
          > running that might also help. I'm thinking everything I have it to
          old, I don't
          > remember seeing anything like that in the settings on any of them.
          >
          > --
          > GB & 73's
          > KA5OAI
          > Sam Morgan
          >
        • Sparkes, John
          Yep, same here. Big peak at 0 with no inputs to D44. Totally goes away when 9V battery powered SR40V6 on-line. John JX________________________________From:
          Message 4 of 21 , Oct 2, 2006
          • 0 Attachment
            Yep, same here. Big peak at 0 with no inputs to D44. Totally goes away when 9V battery powered SR40V6 on-line.
             
            John JX


            From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On Behalf Of Mike
            Sent: Sunday, 1 October 2006 00:41
            To: softrock40@yahoogroups.com
            Subject: [softrock40] Re: Big signal at 0 Hz even with SR40 is off

            The big signal is 60 Hz pickup. The solution is isolation transformer
            (s), in the audio lines and/or at the antenna connection. Running on
            battery can help to, or a non-grounded power cube. These will help to
            reduce the mountain at the center but may not eliminate it entirely.

            73 - Mike WA8BXN

            This message and any attached files may contain information that is confidential and/or subject of legal privilege intended only for use by the intended recipient. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, be advised that you have received this message in error and that any dissemination, copying or use of this message or attachment is strictly forbidden, as is the disclosure of the information therein. If you have received this message in error please notify the sender immediately and delete the message.
          Your message has been successfully submitted and would be delivered to recipients shortly.