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Re: [softrock40] Re: Interference from PC?

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  • Rein A. Smit
    Hi Tony, Thanks for your reply. From looking to the picture on one off the softrock pages I got the idea that the board was directly plugged into an USB
    Message 1 of 41 , Sep 17, 2005
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      Hi Tony,


      Thanks for your reply. From looking to the picture on one off the
      softrock pages
      I got the idea that the board was directly plugged into an USB connector
      of the
      computer. Looking more careful it seems the board is running from an USB
      cable connector?
      My question was more in general, not softrock specific. I was surprised
      to see an unshielded
      front-end that close to a PC

      I have been playing quite a bit with Linrad Spectran dspblaster etc just
      running off a TS 850 at least
      30 ft from the PC and I get all kinds of stuff from the computer. In
      fact it means that I will have to
      put the computer in a second box with all inputs and outputs well
      decoupled I think. This is just
      monitoring basically antenna noise.

      I am expecting a board shortly and will let you know, using the Delta44
      sound card.

      73 Rein W6/PA0ZN

      kb9yig wrote:

      > Hi Rein,
      >
      > I have built about 25 of the v4.0 SoftRock40 receivers and find the PC
      > noise does not cause much of a problem. When the receiver is
      > calibrated to S9, (-73 dBM, 50 uV RMS), the baseline is around -135
      > dBm with 10-15 dB spikes riding on the baseline every 1 kHz or so.
      > Also at the LO frequency, around 7.054-7.056 MHz there is a large
      > broad spike associated with the LO and the fact that the soundcard
      > contributes lots of noise near zero frequency.
      >
      > I will be quite interested in the experience of SoftRock40 builders as
      > they finish their kits. If I can help with problems in getting the
      > little receive running, I would be happy to do so.
      >
      > 73,
      > Tony KB9YIG
      >
      > --- In softrock40@yahoogroups.com, "observer35" <rein0zn@i...> wrote:
      > > Hi all,
      > >
      > > Just new to the group.
      > >
      > > Does anybody experience interference from the PC on 40 meters?
      > >
      > > What about noise and garbage on the 5 V USB line?
      > >
      > > 73 Rein W6/PA0ZN
      > >
      > > http://www.nitehawk.com/linrad_dat/
      >
      >
      >
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    • Bob Hillard
      Rein, When I operate on the low bands (40M thru 160M) I have to turn off my PC s. In fact I sometimes have had to unplug them completely, as the power supply
      Message 41 of 41 , Oct 29, 2005
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        Rein,

        When I operate on the low bands (40M thru 160M) I have to turn off my
        PC's. In fact I sometimes have had to unplug them completely, as the
        power supply isn't completely off when the On/Off switch is in the Off
        position.

        I found the problem to be caused by the computer's switching power
        supply. In fact I lost a power supply in one of my computers recenly,
        and replaced it with a better grade supply, and then was happy to find
        that the noise from that computer was gone.

        Try unplugging your computer completely and see if that quiets things
        down.

        Bob WA6UFQ

        --- In softrock40@yahoogroups.com, "observer35" <rein0zn@i...> wrote:
        >
        > Hi all,
        >
        > Just new to the group.
        >
        > Does anybody experience interference from the PC on 40 meters?
        >
        > What about noise and garbage on the 5 V USB line?
        >
        > 73 Rein W6/PA0ZN
        >
        > http://www.nitehawk.com/linrad_dat/
        >
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