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Re: [softrock40] A useful trick

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  • Cecilio Bayona
    ... The other day on the FlexRadio reflector there was a discussion of transformers to buffer the audio, there was a mention of Jensen transformers and I
    Message 1 of 2 , Sep 28, 2006
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      Edward Gisske wrote:
      > I was having a big problem with ground loops among my computer, station
      > ground, Softrock 40 and a MFJ switching power supply. This was evidenced by
      > a whole lot of really nasty hash showing up on the output of the sound card.
      > The spectrum display looked like a comb!
      >
      > The fix was to put a $14 Radio Shack dual isolation transformer in the sound
      > card input lines. I was worried that the transformer might roll off at the
      > ends of the spectrum, but it appears to be reasonably flat to 48 KHz. The
      > phase/amplitude balance between the sections of the transformer seems to be
      > acceptable as well, as the image rejection still seems fine.
      >
      > Easy!
      >
      > 73,
      > Ted
      > K9IMM
      >
      >
      The other day on the FlexRadio reflector there was a discussion of
      transformers to buffer the audio, there was a mention of Jensen
      transformers and I looked some of them up. 20H to 200KHz flat as a
      pancake, wow, so was the price, over $150 each.

      Mouser has some that are in that range for $15 each, not quite so low in
      frequency response which is OK since it helps get rid of any 50/60Hz pickup.


      --

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


      "Sacred Cows make the best Hamburger!" Don Seglio Batuna
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