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Re: [softrock40] USB and SR V9

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  • Alan
    ... From:
    Message 1 of 5 , Mar 2, 2010
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    ----- Original Message -----
    From: <martinpd
    Subject: [softrock40] USB and SR V9


    > Just wondering if anyone has tried powering their SR9 from USB power only?
    > P.
    >

    Attached v4 circuit. May need adjustment v9 takes more current.

    I have done it with a regulator. Mine seemed OK but watch out for unwanted
    noise/spurs.

    73 Alan G4ZFQ
  • martinpd@roadrunner.com
    Thanks for the reply. I didn t realize the USB power would be dirty. I was just thinking to simplify my setup when going portable. Better leave well enough
    Message 2 of 5 , Mar 2, 2010
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      Thanks for the reply. I didn't realize the USB power would be dirty. I was just thinking to simplify my setup when going portable. Better leave well enough alone - so batteries it is.
      Paul
      ---- k5nwa <k5nwa@...> wrote:
      > At 10:28 AM 3/2/2010, martinpd@... wrote:
      > >Just wondering if anyone has tried powering their SR9 from USB power only?
      > >P.
      >
      > The very first SoftRock did that, the Softrock40, although it sounds
      > nice in principle, the USB power is very dirty and it caused a lot of
      > issues with noise around 0 frequency. With some heavy filtering it
      > may work, and it may work on some PCs but generally it's not a great
      > thing to do.
      >
      > A Pi LC filter may remove the noise without loosing too much voltage
      > so you may want to try that.
      >
      >
      >
      > Cecil
      > K5NWA
      > www.softrockradio.org www.qrpradio.com
      >
      > "Blessed are the cracked, for they shall let in the light."
      >
    • k5nwa
      ... Besides the LC filter, something else worth trying is a Capacitive Multiplier look it up on Google but basically it s a moderate power, high gain
      Message 3 of 5 , Mar 2, 2010
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        At 12:31 PM 3/2/2010, you wrote:
        >Thanks for the reply. I didn't realize the USB power would be dirty.
        >I was just thinking to simplify my setup when going portable. Better
        >leave well enough alone - so batteries it is.
        >Paul
        >---- k5nwa <k5nwa@...> wrote:
        > > At 10:28 AM 3/2/2010, martinpd@... wrote:
        > > >Just wondering if anyone has tried powering their SR9 from USB power only?
        > > >P.
        > >
        > > The very first SoftRock did that, the Softrock40, although it sounds
        > > nice in principle, the USB power is very dirty and it caused a lot of
        > > issues with noise around 0 frequency. With some heavy filtering it
        > > may work, and it may work on some PCs but generally it's not a great
        > > thing to do.
        > >
        > > A Pi LC filter may remove the noise without loosing too much voltage
        > > so you may want to try that.
        > >
        > >
        > >
        > > Cecil

        Besides the LC filter, something else worth trying is a "Capacitive
        Multiplier" look it up on Google but basically it's a moderate power,
        high gain transistor;
        Collector to USB power source
        Emitter is the output
        A resistor,let's say 1K Ohms from the collector to the base
        two modest capacitor lets say 100 uf from collector to ground, and
        from base to ground

        It's good at filtering noise, but you will loose .7V



        Cecil
        K5NWA
        www.softrockradio.org www.qrpradio.com

        "Blessed are the cracked, for they shall let in the light."
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