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Who has played around feeding a DAX IQ output into PowerSDR?

Duane  N9DG
Duane N9DG Member ✭✭
edited March 2017 in SmartSDR for Windows
Spent some time this evening playing around with using a DAX IQ output into a PowerSDR session for RX use. It basically works, but found a few issues:

1. I/Q are inverted – so for example to hear 40M LSB in PowerSDR you must use USB, and of course the spectrum frequency display is also inverted. Unfortunately I do not see a way to swap left/right (I/Q) on the DAX set up side, and PowerSDR does not allow that either from what I can tell. HDSDR does allow this which has proven handy.
 
2. Even though I have DAX set up for 192 kHz there is a distinct roll-off of the signals at about 160 kHz of spectrum width. So my impressions are that the is the nature of the “filtering” to generate DAX I/Q output.

3. The signal and noise spectrum levels seen in PowerSDR seem to be about 40 dB “louder” than they should be. So that makes me wonder, is the DAX I/Q output 16 or 24 bits? I suspect that PowerSDR is expecting that a 192 kHz “unsupported” sound card to be 24 bits.


Why do this? Because it is possible. And I just want to see just how much of this kind of functionality is actually all possible. Though I do also want to peak at some signal processing and recovered audio traits of SmartSDR vs. PowerSDR vs. various other I/Q “sound card” SDR programs that are out there. And to do so simultaneously with each of those different SDR programs being fed from the 6K hardware.

Answers

  • DH2ID
    DH2ID Member ✭✭✭
    edited March 2017
    Duane, I think that you'll get more interesting results, if you feed DAX I/Q into a
    good spectrum analyzer program.

    I like DL4YHF's SpecLab (and his other programs):

    http://www.qsl.net/dl4yhf/spectra1.html

    You'll get exact measurement and time markers and a plethora of other
    possibilities out of this.

    This is a 96k spectrum of the 20m-band here at Karlsruhe with the center
    in the digimode sector at 14.076 (ignore the VFO setting, as CAT is
    not supported - and unecessary - for the Flex radios):

    image

    I also use this program to receive and measure VLF stations like the
    Alexanderson alternator at 17,2kHz with my SDR-IQ, which is directly
    supported.

    PowerSDR is - by itself - a great program for my older Flex radios, but methinks
    not a great program for signal detection and measurement.

    73, Alex-DH2ID
  • Cal Spreitzer - N3CAL
    edited March 2017
    I had once thought about feeding DAX IQ into HDSDR.  It would be nice to use HDSDR's recording feature but it's not possible unless someone comes up with a external .dll for the program??  I don't believe there is one out there anywhere? 

    Cal/N3CAL
  • DH2ID
    DH2ID Member ✭✭✭
    edited December 2016
    Cal, I run HDSDR here with OmniRig, works absolutely fine, CAT and
    PTT works, start up with HamLib, using ExtIO_HamLib.dll

    image

    OmniRig setup:

    image

    Notice that I have set up COM8, that is an extra port created in
    SmartCAT. All extra programs beside the main CAT program
    (In this case MiniDeluxe) should run on extra CAT ports:

    image

    I work 99,99% digital modes: PSK, JT, RTTY, Olivia, MFSK, **** and Domino
    on HF (and CW also, which is a semi-digital mode) and D-Star and FDV on
    HF and VHF.

    73, Alex DH2ID
  • Cal Spreitzer - N3CAL
    edited November 2015
    Thanks for the info Alex!  I'll have to give it a try. 

    73 de Cal/N3CAL
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    1. I/Q are inverted – so for example to hear 40M LSB in PowerSDR you must use USB, and of course the spectrum frequency display is also inverted. Unfortunately I do not see a way to swap left/right (I/Q) on the DAX set up side, and PowerSDR does not allow that either from what I can tell. HDSDR does allow this which has proven handy. 

    Yes, this is a known issue with PowerSDR.  The I/Q channels were swapped from the de facto standard in PowerSDR due to the channel being swapped with the FLEX-5000.

    2. Even though I have DAX set up for 192 kHz there is a distinct roll-off of the signals at about 160 kHz of spectrum width. So my impressions are that the is the nature of the “filtering” to generate DAX I/Q output.

    This is normal. 

    3. The signal and noise spectrum levels seen in PowerSDR seem to be about 40 dB “louder” than they should be. So that makes me wonder, is the DAX I/Q output 16 or 24 bits? I suspect that PowerSDR is expecting that a 192 kHz “unsupported” sound card to be 24 bits.

    SmartSDR is set for 192k @ 24-bit.  PowerSDR will be set to how the VAC cable is configured.


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