# Help about gr-ieee802-11

**URL:** <https://www.ruby-forum.com/t/help-about-gr-ieee802-11/242658>\
**Category:** GNU Radio\
**Created:** [July 13, 2015, 5:56am UTC](https://www.ruby-forum.com/t/help-about-gr-ieee802-11/242658 "2015-07-13T05:56:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [July 13, 2015, 5:56am UTC](https://www.ruby-forum.com/t/help-about-gr-ieee802-11/242658/1 "2015-07-13T05:56:33Z")

</div>

hi.i am newbie using gnuradio.when i try run the wifi\_loopback is comes  
out with this,

Preferences file: /home/userr/.grc  
Block paths:  
/usr/local/share/gnuradio/grc/blocks  
/home/userr/.grc\_gnuradio

Loading: “/home/userr/gr-ieee802-11/examples/wifi\_loopback.grc”

> > > Done

Showing: “/home/userr/gr-ieee802-11/examples/wifi\_loopback.grc”

Generating: “/home/userr/gr-ieee802-11/examples/wifi\_loopback.py”

> > > Warning: This flow graph may not have flow control: no audio or RF hardware  
> > > blocks found. Add a Misc-\>Throttle block to your flow graph to avoid CPU  
> > > congestion.

Generating: “/home/userr/gr-ieee802-11/examples/wifi\_loopback.py”

> > > Warning: This flow graph may not have flow control: no audio or RF hardware  
> > > blocks found. Add a Misc-\>Throttle block to your flow graph to avoid CPU  
> > > congestion.

Executing: “/home/userr/gr-ieee802-11/examples/wifi\_loopback.py”

linux; GNU C++ version 4.8.2; Boost\_105500;  
UHD\_003.008.002-135-ga393ec83

Using Volk machine: avx\_64\_mmx  
OFDM MAPPER: encoding: 0  
set\_min\_output\_buffer on block 10 to 48000  
set\_min\_output\_buffer on block 14 to 100000  
set\_min\_output\_buffer on block 15 to 10000  
set\_min\_output\_buffer on block 17 to 48000  
set\_min\_output\_buffer on block 28 to 48000

> > > Done (return code -11)

i also try with this

(gdb) run /PATH\_TO\_THE\_WIFI\_LOOPBACK\_FILE/wifi\_loopback.py  
Starting program: /PATH\_TO\_THE\_WIFI\_LOOPBACK\_FILE/wifi\_loopback.py  
No executable file specified.  
Use the “file” or “exec-file” command.  
(gdb) exec-file  
No executable file now.  
(gdb) file  
No executable file now.  
No symbol file now.  
(gdb) backtrace  
No stack.

below is my system info:  
user@userr-X455LDB:~$ python -V  
Python 2.7.6  
user@userr-X455LDB:~$ gnuradio-config-info -v  
3.7.7.1  
user@userr-X455LDB:~$ uname -a  
Linux userr-X455LDB 3.13.0-53-generic #89-Ubuntu SMP Wed May 20 10:34:39  
UTC 2015 x86\_64 x86\_64 x86\_64 GNU/Linux  
user@userr-X455LDB:~$ gcc --version  
gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2  
Copyright © 2013 Free Software Foundation, Inc.  
This is free software; see the source for copying conditions. There is  
NO  
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR  
PURPOSE.

user@userr-X455LDB:~$ cat /etc/lsb-release  
DISTRIB\_ID=Ubuntu  
DISTRIB\_RELEASE=14.04  
DISTRIB\_CODENAME=trusty  
DISTRIB\_DESCRIPTION=“Ubuntu 14.04.2 LTS”

what can i do? i hope you can help me.  
thanks