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

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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.
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Duane N9DG

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Posted 4 years ago

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Alex - DH2ID, Elmer

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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):



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
(Edited)
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Cal Spreitzer - N3CAL

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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
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Alex - DH2ID, Elmer

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Cal, I run HDSDR here with OmniRig, works absolutely fine, CAT and
PTT works, start up with HamLib, using ExtIO_HamLib.dll



OmniRig setup:



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:



I work 99,99% digital modes: PSK, JT, RTTY, Olivia, MFSK, Hell 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
(Edited)
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Cal Spreitzer - N3CAL

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Thanks for the info Alex!  I'll have to give it a try. 

73 de Cal/N3CAL
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Tim - W4TME, Customer Experience Manager

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Official Response
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.