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Re: [softrock40] image rejection help

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  • Alan
    ... Subject: [softrock40] image rejection help ... Are signals exactly the same each side? Is there absolutely no difference? I d think there would either have
    Message 1 of 3 , Mar 25, 2013
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      ----- Original Message -----
      Subject: [softrock40] image rejection help


      >I can use some help. I am finishing up the rx ensemble II. I am getting a mirror image on HDSRD. I have carefully gone through
      >the image reduction help link at end of the build. Here is what I am confident on:
      > 1 T1 and T2 have been wired for correct phasing per updates.
      > 2. Sound card, xonar ds is set to line in and I can get two separate inputs. tested inputs. monitoring is off.
      > 3. The left channel I has a lower input than the right side Q when both are set to the same input level. But op amp tests out.
      > 5. When performing the testing of the op amp.
      > 6. I have gone and checked all of the components, I am not seeing anything wrong.
      >

      Are signals exactly the same each side?
      Is there absolutely no difference?
      I'd think there would either have to be a very big difference in the IQ signal levels for no difference to be seen.
      Or that the signals were exactly the same because they were shorted together.
      If there is a big difference between each signal then component differences (R25/26?) or bad soldering around the mixer might cause
      it.
      As Warren says a good stable signal is useful for this kind of investigation.
      An alternative is to run a transceiver at low power into a dummy load.

      73 Alan G4ZFQ
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