QRPLabs QDX and SDRConsole issues?

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

QRPLabs QDX and SDRConsole issues?

#1

Unread post by KA6MOK »

Anyone try using a QDX with SDRConsole? https://qrp-labs.com/qdx.html Recent firmware has allowed a I/Q output, so the full 48khz bandwidth can be used. Someone on their forums mentioned he was able to get it working using one of the existing radio entries, OmniRig and the External Radio interface.

I've tried this and it sort of works, but I'm finding odd tuning effects. Offsets, the spectrum you were looking at changes and isn't what the dial indicates anymore when you change frequency a few khz, and such. Using the Softrock XTAL radio entry, with some nonzero freq, and Kenwood TS440 set in OmniRig (default control set that works fine for the QDX with other software) I'm still not sure this is some issue with the QDX, or just tuning interface issues.

I wouldn't mind coordinating debugging of this between Simon of QRPLabs and you on figuring this out. Would be very nice to have the Console be able to run the QDX for general coverage RX use.

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

Re: QRPLabs QDX and SDRConsole issues?

#2

Unread post by KA6MOK »

Nobody else trying a QDX?

I've looked at this a bit closer, what seems to be happening is that both the spectrum window and the RX window get moved, as the RX window gets tuned by the RX frequency. Normal operation is, of course, the RX window moving up and down inside the waterfall view, while the waterfall view stays the same piece of spectrum, unless you drag it around with the bar at the bottom, or maybe at some point beyond it's re centered on/near the RX window.

What I seem to be seeing is, when the main tuning is moved, both the RX window AND the waterfall window move, in opposite directions. Example, I'm tuned to WWV on 10.000mhz, if I move up to 10.010mhz, the RX window goes up to 10.010mhz, but the whole spectrum moves DOWN 10khz and I now see WWV appearing on 9.990mhz. The opposite happens if I tune down in frequency. Things are only lined up correctly when the the spectrum is centered on the RX frequency.

Just to mention, I have correct Console operation with RTL-SDR's and RSP2, this happens only on the QDX. I have no idea why the Softrock XTAL is a good (or bad) choice to emulate a QDX...

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

Re: QRPLabs QDX and SDRConsole issues?

#3

Unread post by KA6MOK »

Nobody else trying a QDX?

I've looked at this a bit closer, what seems to be happening is that both the spectrum window and the RX window get moved, as the RX window gets tuned by the RX frequency. Normal operation is, of course, the RX window moving up and down inside the waterfall view, while the waterfall view stays the same piece of spectrum, unless you drag it around with the bar at the bottom, or maybe at some point beyond it's re centered on/near the RX window.

What I seem to be seeing is, when the main tuning is moved, both the RX window AND the waterfall window move, in opposite directions. Example, I'm tuned to WWV on 10.000mhz, if I move up to 10.010mhz, the RX window goes up to 10.010mhz, but the whole spectrum moves DOWN 10khz and I now see WWV appearing on 9.990mhz. The opposite happens if I tune down in frequency. Things are only lined up correctly when the the spectrum is centered on the RX frequency.

Just to mention, I have correct Console operation with RTL-SDR's and RSP2, this happens only on the QDX. I have no idea why the Softrock XTAL is a good (or bad) choice to emulate a QDX...

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Simon G4ELI
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Re: QRPLabs QDX and SDRConsole issues?

#4

Unread post by Simon G4ELI »

Hi,

Doesn't look like it. Maybe ask in the mailing list? Bit fiddly and too time-consuming for me to build one, I'm sure I could get it working.
Simon Brown :shock:
www.sdr-radio.com

Do not send me direct e-mail, thank-you!

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

Re: QRPLabs QDX and SDRConsole issues?

#5

Unread post by KA6MOK »

Any ideas on what's going on with the tuning? Might there be a better radio choice? Have to find the mailing list, didn't know SDRConsole has one.

Edit:
Brief description from the QDX manual of the concerning radio architecture:

5. A high performance, double balanced Quadrature Sampling Detector to mix the incoming
RF signals to baseband and produce I and Q signals.
6. A low noise pre-amplifier for the I and Q signals.
7. High performance 24-bit 48ksps (Kilo Samples Per Second) stereo Analog To Digital
Converter (ADC) chip with 112dB of dynamic range.
8. An embedded Software Defined Radio (SDR) receiver which implements, digitally, a 12kHz
Intermediate Frequency superheterodyne receiver with excellent performance and
unwanted sideband suppression, also implementing a sharp digital filter.
9. An embedded 24-bit 48ksps stereo USB Sound card

Hope that sheds some light on the funny tuning or recommending setting changes.
I know that the QDX isn't a "mainstream" SDR, being optimized for certain digital Ham modes, but it does seem to be a decent radio in its range of operation. The digital mode SW's that run it don't allow any general coverage RX use, or even listening to AM or SSB stations in the ham bands, and that's a bit of a shame.

And, if you mean the QRPLabs list, I have an on going thread there.

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

Re: QRPLabs QDX and SDRConsole issues?

#6

Unread post by KA6MOK »

If you like, I can post some screenshots...

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

Re: QRPLabs QDX and SDRConsole issues?

#7

Unread post by KA6MOK »

At any rate, this seems to be a SDRConsole issue, in that somehow the waterfall window is being moved along with the actual RX window, whenever a "tuning" shift is made. Any idea how that might be happening?

jdow
Posts: 800
Joined: Mon Aug 10, 2020 8:17 pm

Re: QRPLabs QDX and SDRConsole issues?

#8

Unread post by jdow »

Pictures. Tour the tools->options. I believe there is a setting in there regarding tuning and automatically resetting the front end tuning.

Are you saying that the spectrum does not follow the waterfall in the main window? I suspect that would REALLY get Simon's interest.

{^_^}

KA6MOK
Posts: 21
Joined: Fri Jul 02, 2021 9:05 pm

Re: QRPLabs QDX and SDRConsole issues?

#9

Unread post by KA6MOK »

Well, not exactly, but overall, yes.

I'm probably not explaining it as well as I think I am...

Lets see: Arrgh... just put them in Photobucket, and found that no pay PB is no free link to share.
Double Arrgh, Amazon Photo is very clunky, or I just haven't found a way to make a link that will appear here...

Copy and open URL below, if it isn't going to work like we want. Link isn't just to the one pic I wanted to show, its to an album of the 3 pics.

https://www.amazon.com/photos/shared/NK ... Yly9nPdkNO

First pic I would show, look for the one with SDRConsole tuned to WWV on 10.000mhz. Nice known time and frequency reference station. The QDX is giving us a 48khz wide spectrum, with 10.000mhz centered in the middle. Everything is as you would expect.

Second pic, look for 10.010mhz. I tuned up 10khz to 1.010mhz, as you can see in the tuning indicator box. Now, you see the RX bandwidth box, i.e. the green box, is tuned up the waterfall to 10.010, but you see the waterfall tuning moved DOWN 10khz, and you see WWV is erroneously appearing on 9.990mhz, instead of staying where it was on the waterfall at 10.000. Same thing happens, in mirror image, in the other direction. if I tune down, RX tunes down, the waterfall tunes upwards.

Things seem to only line up and be normal, if you center the waterfall on the RX frequency, with the >|< button. And, if you look at the 3d pic, with the QDX tuned on the 20M ham band FT8 frequency of 14.074, you see it doesnt exactly line up, either. All those signals should be just above 14.074, from about 100hz above to about 3200hz above. There's a few khz offset. So, maybe only on round frequency numbers things line up properly? Overall, it seems like the waterfall somehow gets the main tuning info and moves when it shouldn't. Plus maybe a bit more in there.

Anyway, sorry for the difficult picture delivery. Hope with the pics this is a bit clearer.

jdow
Posts: 800
Joined: Mon Aug 10, 2020 8:17 pm

Re: QRPLabs QDX and SDRConsole issues?

#10

Unread post by jdow »

I don't see anything actually running. There are camera icons sprinkled around SDR Console for creating screen shots of the window with the camera button you used. Then for uploading videos click on "Full Editor & Preview". There is an icon for uploading images. At a guess you do not have communications between SDRC and your radio. The sdr-radio web site has instructions for setting that up. I doubt you can make it work with QDX unless it has some suitable command set OmniRig understands.
{o.o}

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