# Smith Chart in GNU Radio

**URL:** <https://www.ruby-forum.com/t/smith-chart-in-gnu-radio/240316>\
**Category:** GNU Radio\
**Created:** [April 8, 2014, 10:53am UTC](https://www.ruby-forum.com/t/smith-chart-in-gnu-radio/240316 "2014-04-08T10:53:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [April 8, 2014, 10:53am UTC](https://www.ruby-forum.com/t/smith-chart-in-gnu-radio/240316/1 "2014-04-08T10:53:23Z")

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Hi

I am trying to figure out how to use smith chart as a sink in GNU Radio.  
I made an OOT ([GitHub - mitul93/gr-smithchart: pyQT based smith chart for GNU Radio](https://github.com/mitul93/gr-smithchart)) using pyQT by  
following Tim O’shea’s work.  
It is merely a skeleton, still lots of work to do.

I made two versions of smith chart - one using pyQT and another using  
matplotlib (ploar plot).  
After executing example\_smithsink\_numpy.py when I close the graph, the  
program won’t stop. I tried to write an close\_event() for the graph, but  
it  
didn’t work. Is it happening due to the fact I am using it with GNU  
Radio?

To display data point on graph, shall I use message passing or simple  
vector input?

Also please give me your feedback about expected function that I must  
implement in smith chart.

Thanks  
Mitul Vekariya  
Institute of Technology  
Nirma University

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**Author:** ![MITUL\_VEKARIYA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/57b2e6/32.png) [@MITUL\_VEKARIYA](https://www.ruby-forum.com/u/MITUL_VEKARIYA)\
**Post date:** [April 9, 2014, 4:26am UTC](https://www.ruby-forum.com/t/smith-chart-in-gnu-radio/240316/2 "2014-04-09T04:26:04Z")

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Hello

Problem solved. I removed the QApplication() from the example.  
Matplotlib  
was used for plotting, no need of qApp!!

Thanks  
Mitul Vekariya