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Re: DSP Radio OS X 10.7 Strange Behavior

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  • m0gzg
    Hi Chase ... I use DSP Radio with both an Ensemble RXTX 40/30/20 and a 40 M RX only Softrock, and the results are good. I also have the opportunity to use the
    Message 1 of 4 , Aug 8, 2011
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      Hi Chase

      --- In softrock40@yahoogroups.com, Chase Turner <ke4qdl@...> wrote:
      > >
      > > --- In softrock40@yahoogroups.com, "ke4qdl" <ke4qdl@> wrote:
      > > > Hello,
      > > >
      > > > I've assembled my 40 meter softock and it passed all the checks I was
      > > able to perform from the guide on the excellent WB5RVZ web site. However,
      > > when I attempt to use the SR with my iMac and DSP Radio, strange behavior
      > > occurs, regardless of whether the SR has power applied.
      > > >
      > > > When powered, the display looks like two sidebands on either side of the
      > > center frequency. When not powered, it appears as if I can see some sort of
      > > harmonic coming through, as I see some fairly even signal spacing on the
      > > display.
      > > >
      > > > Has this occurred to anyone else, and if so, what was the remedy? It
      > > seems so very strange that I am receiving a tone when I have no power
      > > applied.
      > > >
      > > > Any help is appreciated, and I will be happy to send along a picture of
      > > the display to anyone who would like one.
      > >
      > >
      > >
      >

      I use DSP Radio with both an Ensemble RXTX 40/30/20 and a 40 M RX only Softrock, and the results are good. I also have the opportunity to use the windows offerings but tend to stick with DSP Radio (so don't give up just yet!

      My Mac is as follows:

      2.4 GHz Intel Core 2 Duo (MAC Mini)

      2 GB 1067 MHz DDR3 Memory

      MAC Version 10.6.8

      I use 96KHz sampling speed at 32bit resolution (internal ADCs) and the CPU load is just 10% on my system.

      I believe I may have seen similar to what you are describing, and can make the following suggestions:

      1. Check you have the same output on both left and right from the output of your reciever (ie the Q and I signals which should sound identical albeit 90 degrees out of phase). You could try headphones, or plug into an amplifier (or garage band)!

      2. Spend some time experimenting with your audio / computer grounding system (I think you get a similar effect to that you describe if the _audio ground is broken_, but you may also have a ground loop etc.

      3. Run your receiver on a 9v or 12v battery to eliminate possible PSU problems (and associated grounding).

      4. If still no joy what happens to DSP Radio with no input at all, and with an audio input!

      If all else fails I will happily trade settings (there aren't actually very many).

      Incidentally there are allegedly at least two fuller-featured SDR Radios being developed for the Mac that I know of, but DSP Radio should suit you fine for now.

      GL and 73

      Martyn
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