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Re: HELP: EIA does not work

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  • sv1eia
    Uli, If you want some hints for debugging your rig, check to see if you get proper I and Q signals from its output. I ve indicated an approach with an
    Message 1 of 7 , Oct 31, 2009
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      Uli,

      If you want some hints for debugging your rig, check to see if you get proper I and Q signals from its output.

      I've indicated an approach with an oscilloscope but in case you do not have it, you can measure at least the amplitude of your rig's L and R output with just the PowerSDR-IQ.
      First plug just one channel (either left or right) and move to 7100KHz, set your generator to 7100KHz and see how many dBm you actually see as maximum on the panadapter (no need to do any image rejection since you will have only one channel) then un-plug this channel and plug in the other one, and do the same check.
      If both of the channels give the same dBm indication, at least you know that both channels are output from your rig equally and that is ok, if on the other hand the dBm readings on left alone and right alone channels differ, then you have started to spot the problem and need to see on your rig why one channel is not performing ok.

      I hope these help.

      73,
      Christos SV1EIA




      --- In powersdr-iq@yahoogroups.com, uli <uli@...> wrote:
      >
      > Hi Christos,
      >
      > many thanks for your quick reply.
      > I think the fault is in the hardware.
      > With my SoftRock EIA works very good.
      >
      > Many thanks for the hints.
      >
      > 73
      > Uli
      > DF5SF
      >
      > > Uli,
      > >
      > > See my remarks in '='
      > >
      > > --- In powersdr-iq@yahoogroups.com, "ulidf5sf2002" <uli@> wrote:
      > > >
      > > > Hi Christos,
      > > >
      > > > after new installation (I deleted the old directory) of PowerSDR-IQ the following happens:
      > > >
      > > > VFO A : 7024,0 kHz USB 2,4 kHz and the IF=9kHz
      > > >
      > > > now I use a signal generator for Level Calibration. The generator has an S9 Signal (-73dBm) on 7025kHz.
      > >
      > > = What is the level calibration you are performing? Level Calibration with a signal generator is performed to accurately set the S-Meter and dBm indication.
      > > Are you referring to the Rx Image Rejection Calibration button?
      > >
      > > > After level calibration the Image is at abt. 7004,950kHz with -99dBm. The 26dB are my hardware image rejection.
      > >
      > > = If you want to see your hardware rejection image you have to un-check the Effective Image Adjustment button and also place in the zero position the Phase and Gain sliders in Setup->DSP->Image Reject.
      > >
      > > > EIA has 0.9 and after clicking EIA (now yellow) and waiting for 1min -> nothing happend.
      > >
      > > = If you have a S9+30 signal in your panadapter and engage the EIA with 0.900 coefficient setting, it has to nullify immediately the image signal up to ~ your ADC dynamic range.
      > >
      > > >
      > > > Now I decreased the power of the generator to S9+30dB (-43dBm). Suddenly EIA works and the image is down to abt. -110dBm. So the rejection is 67dB.
      > >
      > > = I'm a bit confused here, you mention 'decreased' to -43dBm whereas before you mentioned -73dBm.. that is increased. If you had higher than S9+30 (+40,+50) you might reached a saturation point of your audio card (or your rig..) and ADC is overloading.
      > >
      > > >
      > > > Decreasing the generator level I get the following (EIA yellow):
      > > >
      > > > generator -54dBm image -102dBm rejection 48dB
      > > > generator -64dBm image -102dBm rejection 38dB
      > > > generator -73dBm image -92dBm rejection 20dB
      > > > generator -83dBm image -102dBm rejection 21dB
      > > > generator -92dBm image -108dBm rejection 16dB
      > > >
      > > > At the last 3 measurements there is no difference between EIA (yellow) and EIA inactive.
      > > >
      > > > My Soundcard is a EMU-0202 with ASIO and the SDR is a german project called LIMA,
      > > > (see here in German: http://www.darc.de/distrikte/l/02/sdr/con_anleitung.shtml)
      > > >
      > >
      > > = I do not reckon that this is normal behaviour, it seems that there are no proper quadrature I and Q signals. That comes down to Left and Right stereo audio. Check again your audio cables, your stereo/mono situation, possible gain problems in one channel either left or right.
      > >
      > > > Now what to do ?
      > > > Do you need more meassurements ?
      > >
      > > = As I said, disengage the EIA button and see with image calibration sliders in zero position (Phase/Gain) what is your image rejection.
      > > Check with EIA disengaged if you can have image rejection by using the Phase/Gain dials manually.
      > >
      > > = Check the I and Q signals if they are in quadrature and have a decent 90 degrees phase difference between them, that can be accomplished by setting your generator to 7100KHz, set your IF shift (from the expert setup page) to 0Hz and set VFOA to 7099KHz.
      > > = With this setup if you connect an oscilloscope in audio out of your rig directly, eg X osc channel to I (Left) and Y osc channel to Q (Right) you have to see on your oscilloscope two sinewaves of 1KHz each having 90 degrees phase difference between them. If the sinewaves do not have 90 degrees diff, or their amplitude is quite different between them, then there is something wrong in your rig.
      > >
      > > >
      > > > 73
      > > > Uli
      > > > DF5SF
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > 99d
      > > >
      > > > --- In powersdr-iq@yahoogroups.com, "sv1eia" <sv1eia@> wrote:
      > > > >
      > > > > Uli,
      > > > > One more thing, check the EIA setting, if it is 0.000 then it does not do any image rejection, put a value eg 0.900
      > > > >
      > > > > 73,
      > > > > Christos SV1EIA
      > > > >
      > > > >
      > > > >
      > > > >
      > > > > --- In powersdr-iq@yahoogroups.com, "sv1eia" <sv1eia@> wrote:
      > > > > >
      > > > > > Uli,
      > > > > >
      > > > > > Check if for some reason your audio is mono instead of stereo now with your new installation.
      > > > > > Also check to see if you have any kind of image rejection with the usual old way of the manual phase/gain sliders.
      > > > > >
      > > > > > 73,
      > > > > > Christos SV1EIA
      > > > > >
      > > > > >
      > > > > >
      > > > > >
      > > > > > --- In powersdr-iq@yahoogroups.com, "ulidf5sf2002" <uli@> wrote:
      > > > > > >
      > > > > > > Hallo,
      > > > > > >
      > > > > > > after new installation of my PC EIA is NOT working. If I click on EIA (yellow) there is no difference in the image.
      > > > > > > With the old installation it worked very fine, over 60dB rejection.
      > > > > > > I have the latest version of PowerSDR-IQ (Febr.21,2009)
      > > > > > >
      > > > > > > Any suggestions ?
      > > > > > >
      > > > > > > tnx
      > > > > > > Uli
      > > > > > > DF5SF
      > > > > > >
      > > > > >
      > > > >
      > > >
      > >
      > >
      > >
      > >
      > > ------------------------------------
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      >
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