# Simple fm tx

**URL:** <https://www.ruby-forum.com/t/simple-fm-tx/230720>\
**Category:** GNU Radio\
**Created:** [July 1, 2014, 3:30pm UTC](https://www.ruby-forum.com/t/simple-fm-tx/230720 "2014-07-01T15:30:04Z")\
**Posts on this page:** 1\
**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:** [July 1, 2014, 3:30pm UTC](https://www.ruby-forum.com/t/simple-fm-tx/230720/1 "2014-07-01T15:30:04Z")

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hello,  
recently i have started to work on usrp b200 and to learn gnuradio.  
for the beginning i have tried to run two example:

1. freq hopping
2. multi freq

when i ran the first one and some errors occurred (attached)  
the second (multi freq) was written to an old version ( not uhd driver)

can you help me to run those programs ?

in addition, i have design a simple fm transmitter that is modulated by  
10khz tone,  
it’s work but not good.  
the signal is stable for 1 minute and then many harmonies arise for few  
second.  
i have tried to fine tune many parameters with no success.  
what am i doing wrong?

tank you.