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Re: Transmitting with HDSDR

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  • lc_hdsdr
    Hi Stuart, when in transmit mode you can measure with some equipment and calibrate with Channel Skew Calibration for TX from the Options menu. kind regards,
    Message 1 of 6 , Jan 5, 2013
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      Hi Stuart,

      when in transmit mode you can measure with some equipment and calibrate with "Channel Skew Calibration for TX" from the Options menu.

      kind regards,
      LC


      --- In softrock40@yahoogroups.com, "s_t_marsh" wrote:
      >
      > Hi,
      >
      > I've just got my ancient RXTX 6.2 working great on receive and using si570 kit for local oscillator tuning. Just about to try transmitting but wonder if I need to adjust output signals for minimum image rejection? I see documentation for doing this in Rocky (which I can't get working on Win7!) but not for HDSDR.
      >
      > Any help/advice greatly appreciated.
      >
      > Stuart
      >
    • s_t_marsh
      Hi LC, Is there any documentation for this feature? Regards, Stuart
      Message 2 of 6 , Jan 5, 2013
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        Hi LC,

        Is there any documentation for this feature?

        Regards,

        Stuart


        --- In softrock40@yahoogroups.com, "lc_hdsdr" wrote:
        >
        >
        > Hi Stuart,
        >
        > when in transmit mode you can measure with some equipment and calibrate with "Channel Skew Calibration for TX" from the Options menu.
        >
        > kind regards,
        > LC
        >
        >
        > --- In softrock40@yahoogroups.com, "s_t_marsh" wrote:
        > >
        > > Hi,
        > >
        > > I've just got my ancient RXTX 6.2 working great on receive and using si570 kit for local oscillator tuning. Just about to try transmitting but wonder if I need to adjust output signals for minimum image rejection? I see documentation for doing this in Rocky (which I can't get working on Win7!) but not for HDSDR.
        > >
        > > Any help/advice greatly appreciated.
        > >
        > > Stuart
        > >
        >
      • Alan
        ... Subject: [softrock40] Re: Transmitting with HDSDR ... Stuart You are familiar with the RX image rejection? Like RX the transmit image will be exactly
        Message 3 of 6 , Jan 5, 2013
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          ----- Original Message -----
          Subject: [softrock40] Re: Transmitting with HDSDR


          >
          > Is there any documentation for this feature?

          Stuart

          You are familiar with the RX image rejection?
          Like RX the transmit image will be exactly opposite from centre to the wanted TX frequency.
          As Warren says use AM/FM mode.
          You find the image on a RX, make sure it really is the weaker image, that IQ swap is correct.
          Then use the sliders to reduce this to a minimum.
          This needs checking every time you move frequency and certainly will vary as you move bands.
          Make notes of the settings at different frequencies.
          Note it is best to press "C" on the keyboard after selecting the TX frequency but before adjusting IQ. This moves the tuning so the
          TX frequency is at a constant audio frequency and reduces the variation as you change the tuning.

          This procedure is much the same for all SDR software with transmit capability.

          73 Alan G4ZFQ
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