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Re: [softrock40] Re: Align LandR with Ensemble RX II

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  • JOHN GREUSEL
    This may not be too relevant to this discussion but one thing I learned from building my Frankenstein sr6.3ng with a homebrew RX bandpass filter is that the
    Message 1 of 9 , May 27 5:41 AM
      This may not be too relevant to this discussion but one thing I learned from building my Frankenstein sr6.3ng with a homebrew RX bandpass filter is that the correct winding and connection of the transformer in that circuit is absolutely essential for good image rejection. I had plenty of signal with it wired wrong but the image rejection was non-existent.

      John
      KC9OJV



      ----- Original Message -----
      From: "nwmonitor@..." <nwmonitor@...>
      To: softrock40@yahoogroups.com
      Cc:
      Sent: Friday, May 27, 2011 7:17 AM
      Subject: Re: [softrock40] Re: Align LandR with Ensemble RX II

      The L/R channels always need to be equal on the sound card input.


      Sent from my BlackBerry® wireless device

      -----Original Message-----
      From: "homebrewer7" <moneycraft@...>
      Sender: softrock40@yahoogroups.com
      Date: Fri, 27 May 2011 09:47:15
      To: <softrock40@yahoogroups.com>
      Reply-To: softrock40@yahoogroups.com
      Subject: [softrock40] Re: Align LandR with Ensemble RX II

      Thanks for the responses. Turns out the image rejection is not that bad at all (unless i really turn one channel up over the other). As for now I found keeping both set all the way CCW to 0 seams to work fine and gives me a standard point for in software calibration.

      Using the auto-tune in winradhd then switching to AM seams to eliminate some of the crazy phase spinning issue.




      --- In softrock40@yahoogroups.com, Bruce Tanner <bet110@...> wrote:
      >
      > Thanks, Bob and Alan. Sorry! to others!  Mine is one of those 'spurious'
      > items mentioned in an earlier message. :)
      >
      > On 5/24/2011 2:23 PM, g8voip wrote:
      > >
      > > Hi Bruce,
      > >
      > > The phase meter in Winrad (HDSDR) has absolutely nothing to do with
      > > setting up the image rejection gain / phase adjustments.
      > >
      > > The phase meter does come in handy when accurately setting the Si570
      > > frequency using WWV or similar. In AM mode, that is when you fine tune
      > > the frequency to slow or halt the rotation when precisely tuned.
      > >
      > > To answer the question posed, the correct way to set up the image
      > > rejection is to input a large stable signal ideally from a generator,
      > > or a good off air signal. It needs to be at least 60 or 70dB larger
      > > than the noise floor to fully optimise the image rejection.
      > >
      > > On that sound device, you need to set a level and then not change it,
      > > otherwise that will affect the image rejection.
      > >
      > > If you set your signal to 15kHz below the centre (zero) frequency, you
      > > should see the image 15kHz above. Hopefully this is already smaller
      > > than the wanted (main signal). If they are the same amplitude then
      > > thereis a problem as the SoftRock hardware usually provides 20 - 30dB
      > > image rejection without any software correction.
      > >
      > > Go to the Winrad menu 'Channel Skew Calibration', then carefully
      > > adjusting the amplitude and phase sliders you should be able to
      > > progressively reduce the image to at least 50 or 60dB below the wanted
      > > signal. It does take a little time and you do need to resort to the
      > > fine sliders for the final adjustments. You will find you have to make
      > > adjustments to each slider in turn to achieve the best image rejection.
      > >
      > > Dont forget to press 'Ok' to save the settings.
      > >
      > > There is no way manually adjusting the level controls on the sound
      > > card will be able to achieve the best image rejection. To achieve 60dB
      > > rejection requires the amplitude of the I and Q signals to be matched
      > > to 0.01dB and phase within 0.1 degree. Very small adjustments make
      > > large differences.
      > >
      > > 73, Bob G8VOI
      > >
      > >
      > > --- In softrock40@yahoogroups.com
      > > <mailto:softrock40%40yahoogroups.com>, Bruce Tanner <bet110@> wrote:
      > > >
      > > > I believe the phase meter should be stationary or close thereto when
      > > the
      > > > phase/gain adjustment is properly set in all modes. You need to go very
      > > > slowly with it to see that occur as there is a bit of delay in the
      > > > action which is normal. Your external adjustments may help in some
      > > > manner but the software should take care of it internally.
      > > > You do not need to raise the gain on the sound card input much beyond
      > > > the point where you can see the signal amplitude stabilize.
      > > >
      > > > Bruce, K2BET
      > > >
      > > > Congrats on your successes so far.
      > > >
      > > > On 5/24/2011 1:10 PM, homebrewer7 wrote:
      > > > >
      > > > > So I got the Ensemble RX II up and running with an E-MU 0204.
      > > Seams to
      > > > > work great. I've used the HDSDR (winradHD) and the SDR-Radio software
      > > > > so far.
      > > > >
      > > > > I just adjust the L and R channel levels on the front of the 0204 to
      > > > > get rid of images. Is there a better way of me doing this? I've only
      > > > > had this up and running for a day now. What I'm looking for is when
      > > > > adjusting the phasing, in HDSDR for example, what am I looking for?
      > > > > Any standard method? Also in AM the phase meter thing just spins like
      > > > > crazy all the time. Is that normal?
      > > > >
      > > > > Thanks and take care.
      > > > >
      > > > >
      > > > >
      > > > >
      > > > > __________ Information from ESET Smart Security, version of virus
      > > > > signature database 6148 (20110524) __________
      > > > >
      > > > > The message was checked by ESET Smart Security.
      > > > >
      > > > > http://www.eset.com
      > > >
      > >
      > >
      > >
      > >
      > > __________ Information from ESET Smart Security, version of virus
      > > signature database 6149 (20110524) __________
      > >
      > > The message was checked by ESET Smart Security.
      > >
      > > http://www.eset.com
      >




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