Re: [Discuss-gnuradio] QT Vector sink question?

[Glen I Langston]

Hi Marcus,

Thanks for your note.  Yes, certainly I know that I should have not had IQ 
balance running now,
but I falsely assumed leaving the default setting would not hurt anything.  
Really a
major time sink, finding this trivial problem…

Concerning your use of the Odroids  did you say use VNC with them or just ssh 
in and run
without graphics display?   If you do use VNC, which VNC program did you 
install?

Thanks again,

Glen



> On Jun 8, 2018, at 11:12 AM, Marcus D. Leech <address@hidden> wrote:
> 
> On 06/08/2018 11:04 AM, Glen I Langston wrote:
>> Hello Gnuradio Aficionados,
>> 
>> In case any has had similar problems with the AIRSPY and spectra aliases,
>> the problem is solved very simply.   Do not heave the IQ balance setting at 
>> “Automatic”
>> as this causes IQ balancing on Linux devices.  This was the cause of our 
>> problems
>> with aliases in the spectra.  The code seems to be OK on Macs but definitely 
>> causes
>> problems on Linux.
>> 
>> Who should I talk to about this and other OSMOSDR issues with Airspy code 
>> for Linux?
>> 
>> Thanks
>> 
>> Glen
>> 
>> PS there was an OSMOSDR Gnuradio companion interface change and I’m confused
>> over what, exactly, the settings for “linearity” and “sensitivity” do for 
>> AIRSPY.
> The I/Q balancing code in gr-osmosdr doesn't work very well with radio 
> astronomy--it will essentially never converge.  It's only really useful for
>  spectra that contain a number of narrow-band features, which, hopefully, 
> radio astronomy doesn't have :)
> 
> Automated I/Q balancing is a subject where there are NO universal "passive" 
> solutions.  Each approach has its place. Radio Astronomy isn't one of
>  them :(
> 
> 
>> 
>>> On May 21, 2018, at 2:50 PM, Glen I Langston <address@hidden> wrote:
>>> 
>>> Hello all,
>>> 
>>> Thanks for all the interesting discussion.  Very educational.
>>> 
>>> I’ve got a pair of questions concerning the QT vector sink.
>>> 
>>> My application uses the vector sink for plotting and diagnostics
>>> of averaged spectra.
>>> 
>>> I’m getting the impression that the QT vector sink is using a good fraction
>>> of my computer resources, despite trying to reduce the update intervals.
>>> 
>>> My question is 1) can I somehow turn off the Min and Max functions and any
>>> averaging of the data in the QT vector plotter?
>>> 
>>> The second question concerns a waterfall plot for the vectors I’m
>>> generating.   The QT waterfall plot does not accept a vector.
>>> If I turn the vector back into a stream, then the QT waterfall plot then
>>> Fourier transforms the spectra back. making a mess.
>>> 
>>> So the Second question: 2) is there a way to provide the QT water fall 
>>> plotter
>>> with a Vector and not have it FFT the data?
>>> 
>>> Thanks
>>> 
>>> Glen
>>> 
>>> FYI The code for Radio Astronomy is currently available
>>> (both observing interface and examples) at:
>>> 
>>> git clone http://www.github.com/glangsto/gr-nsf
>>> 
>>> 
>>> 
>>> 
>> 
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