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Re: [softrock40] Re: Interference from PC?

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  • kd5nwa
    I bought a 16 foot USB extension in case I needed it, and I have matching long audio cables. The monitor is the culprit most of the time, but just in case I
    Message 1 of 41 , Sep 18, 2005
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      I bought a 16 foot USB extension in case I needed it, and I have
      matching long audio cables.

      The monitor is the culprit most of the time, but just in case I have
      a Industrial PC that they were throwing out at work, It's fully
      encased in metal including a grounded cover for the CD/Floppy drive
      area. With it came a 15.1" LCD monitor that I hope will be quieter
      that the regular monitors I have.

      I still have not received my SR-40. When it was first available I
      stayed late and bought some, then next day I was 8th on the list,
      with the current list I'm down to 50 or lower. And people all around
      me have received theirs. It's a conspiracy, I should have worn my
      aluminium hat!

      >I'm brand spankin' new to the group so didn't see the original thread.
      >
      >Expecting a sensitive receiver to operate just inches away from a
      >wideband noise source is optimistic (IMHO). For best results, it
      >needs shielding just like any other receiver and or transmitter does.
      >
      >Computer noise might not show up as clean carriers or be identifiable
      >by tuning across the band. It appears as an elevated noise floor most
      >of the time, which sounds like background noise. I'm sure many people
      >have interference from their own computers and most don't even
      >realize it's there because it sounds rather like normal atmospheric noise.
      >
      >For absolute best results, shield it. For casual listening on a
      >crowded band, don't worry about it and run it as supplied.
      >
      >My softrock-40 is going on LF when I get it and it will be located
      >away from the computer and shielded. Switching supplies, florescent
      >lamps and computer interference is pretty severe at 190 kHz and I
      >want to have good reception. I'm even considering magnetic shielding
      >due to the nature of the interference at these frequencies.
      >
      >Regards,
      >
      >Art
      >
      >
      >
      >
      >
      >>The supply from the USB connector is 5V. Are you using a separate power
      >>supply?
      >
      >
      >--
      >No virus found in this outgoing message.
      >Checked by AVG Anti-Virus.
      >Version: 7.0.344 / Virus Database: 267.11.1/104 - Release Date: 9/16/2005
      >
      >
      >
      >
      >
      >
      >Yahoo! Groups Links
      >
      >
      >
      >


      --
      Cecil
      KD5NWA
      <www.qrpradio.com>

      I fail to see why doing the same thing over and over and getting the
      same results every time is insanity: I've almost proved it isn't;
      only a few more tests now and I'm sure results will differ this time
      ...
    • 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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