# GNU Radio Companion doesn't show the QT GUI Sink

**URL:** <https://www.ruby-forum.com/t/gnu-radio-companion-doesnt-show-the-qt-gui-sink/233945>\
**Category:** GNU Radio\
**Created:** [January 24, 2015, 2:26am UTC](https://www.ruby-forum.com/t/gnu-radio-companion-doesnt-show-the-qt-gui-sink/233945 "2015-01-24T02:26:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [January 24, 2015, 2:26am UTC](https://www.ruby-forum.com/t/gnu-radio-companion-doesnt-show-the-qt-gui-sink/233945/1 "2015-01-24T02:26:00Z")

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Hi,

I am new to GNU Radio, so I built a FM receiver to get started on the  
journey. I created the following .grc file, and when I clicked  
\<\>, I saw the GUI window pop up and exit immediately. The sound  
came out only for less than a second and disappeared as the window sank.  
I’ve researched this problem in this forum awhile, and someone suggested  
it’s probably due to multiple version of gnuradio installed. But I  
cleaned everything related to uhd and gnuradio in my /usr/local  
directories, and reinstalled via the script “build-gnuradio”, it still  
didn’t work. So could you confirm with me whether this is the reason of  
my problem, and if so, where can I check to find the conflicted version?  
And what do you suggest me do?

I can do uhd\_fft successfully, which opens up a window and never quit.

I am using ubuntu 14.04, usrp b210. I used “build-gnuradio” to install  
everything. It turned out that grc is 3.7.6.1, with uhd being 3.8.1

Here’s the output of doing \<\>. It ended with “DONE”, and  
windows quit

* * *

linux; GNU C++ version 4.8.2; Boost\_105400;  
UHD\_003.008.001-105-g91ae742f

## – Loading firmware image: /usr/local/share/uhd/images/usrp\_b200\_fw.hex… done – Loading FPGA image: /usr/local/share/uhd/images/usrp\_b210\_fpga.bin… done – Operating over USB 3. – Detecting internal GPSDO… No GPSDO found – Initialize CODEC control… – Initialize Radio control… – Performing register loopback test… pass – Performing register loopback test… pass – Performing CODEC loopback test… pass – Performing CODEC loopback test… pass – Asking for clock rate 32.000000 MHz… – Actually got clock rate 32.000000 MHz. – Performing timer loopback test… pass – Performing timer loopback test… pass – Setting master clock rate selection to ‘automatic’. – Successfully tuned to 107.300000 MHz

Using Volk machine: avx\_64\_mmx\_orc

> > > Done

* * *

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<div class="post-metadata">

**Author:** ![dxi](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/278dde/32.png) [@dxi](https://www.ruby-forum.com/u/dxi)\
**Post date:** [February 5, 2015, 6:55am UTC](https://www.ruby-forum.com/t/gnu-radio-companion-doesnt-show-the-qt-gui-sink/233945/2 "2015-02-05T06:55:43Z")

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I have the same problem. I try to just use a Signal Source, a Throttle,  
and a QT GUI Sink. When I execute the flowgraph the QT GUI Sink window  
appears very briefly. The command window says that it generates  
top\_block.py and then it executes top\_block.py Using Volk machine:  
avx\_64\_mmx\_orc and then I get \>\>\>Done

If I change the top\_block to use the WX GUI and I use the WX GUI Scope  
Sink instead of the QT GUI Sink everything works fine. I use GNU Radio  
Companion 3.7.6.1 in Ubuntu 14.04/