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RE: [softrock40] Re: Softrock sensitivity.

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  • Tony Parks
    Hi Martin, The feedback resistors are supposed to be 4.99k resistors. The schematic page for the Lite II kit is included with this note. 73, -- Tony Parks
    Message 1 of 35 , Jun 1, 2011
    Hi Martin,

    The feedback resistors are supposed to be 4.99k resistors.  The schematic page for the Lite II kit is included with this note. 

    73,
    --
    Tony Parks
    kb9yig@...
    http://www.kb9yig.com
    
    


    On Wed, 2011-06-01 at 17:04 +0700, Martin Sole wrote:
     
    Okay, well I’m not convinced it’s working right yet. Here’s another thing I have just noted. In addition to the Lite I that  am referring to I also have a TXRX 6.2 partially built for 20 and 30 metres. The receiver seems noticeably livelier. Connecting an antenna makes the noise jump up a good 10dB on 30 or 20 but has no obvious effect on the noise with the Lite II. About the only thing I can figure is a difference with the op-amp. The 6.2 and 6.3 have LT6231 op amps with 4.99k resistors in the feedback but the Lite II has the same LT6231 op-amp (changed from a TLV2462) but with 1k resistors in the feedback. It also has 1 resistors in the op –amp output. Just wondering about that.

     

    Regards

    Martin, HS0ZED

     

     

    From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On Behalf Of Alan
    Sent: 01 June 2011 15:41
    To: softrock40@yahoogroups.com
    Subject: Re: [softrock40] Re: Softrock sensitivity.


     

     


    ----- Original Message -----
    Subject: RE: [softrock40] Re: Softrock sensitivity.

    >
    > I'm still left with not being able to hear much below 1uV and that seems
    > to
    > me to be about 20dB deafer than I would expect.
    >

    Martin,
    Sorry but I'm not familiar with how the figures compare with actual
    audibility.
    If you search the messages you will find what others have said.
    for example <http://groups.yahoo.com/group/softrock40/message/53438>

    73 Alan G4ZFQ



  • R. R. (Robby) Robson
    http://www.wb5rvz.com/sdr/sr_lite_ii/04_opamp.htm ... -- Cheers, Robby Richard R. (Robby) Robson Amateur Radio Station WB5RVZ www.wb5rvz.com
    Message 35 of 35 , Jun 2, 2011
    • 0 Attachment
      http://www.wb5rvz.com/sdr/sr_lite_ii/04_opamp.htm

      On Wed, Jun 1, 2011 at 5:35 AM, Tony Parks <kb9yig@...> wrote:
       
      [Attachment(s) from Tony Parks included below]

      Hi Martin,

      The feedback resistors are supposed to be 4.99k resistors.  The schematic page for the Lite II kit is included with this note. 

      73,

      --
      Tony Parks
      kb9yig@...
      http://www.kb9yig.com
      
      


      On Wed, 2011-06-01 at 17:04 +0700, Martin Sole wrote:
       
      Okay, well I’m not convinced it’s working right yet. Here’s another thing I have just noted. In addition to the Lite I that  am referring to I also have a TXRX 6.2 partially built for 20 and 30 metres. The receiver seems noticeably livelier. Connecting an antenna makes the noise jump up a good 10dB on 30 or 20 but has no obvious effect on the noise with the Lite II. About the only thing I can figure is a difference with the op-amp. The 6.2 and 6.3 have LT6231 op amps with 4.99k resistors in the feedback but the Lite II has the same LT6231 op-amp (changed from a TLV2462) but with 1k resistors in the feedback. It also has 1 resistors in the op –amp output. Just wondering about that.

       

      Regards

      Martin, HS0ZED

       

       

      From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On Behalf Of Alan
      Sent: 01 June 2011 15:41
      To: softrock40@yahoogroups.com
      Subject: Re: [softrock40] Re: Softrock sensitivity.


       

       


      ----- Original Message -----
      Subject: RE: [softrock40] Re: Softrock sensitivity.

      >
      > I'm still left with not being able to hear much below 1uV and that seems
      > to
      > me to be about 20dB deafer than I would expect.
      >

      Martin,
      Sorry but I'm not familiar with how the figures compare with actual
      audibility.
      If you search the messages you will find what others have said.
      for example <http://groups.yahoo.com/group/softrock40/message/53438>

      73 Alan G4ZFQ






      --
      Cheers,
      Robby
       
      Richard R. (Robby) Robson
      Amateur Radio Station WB5RVZ

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