# Spectrum record

**URL:** <https://www.ruby-forum.com/t/spectrum-record/231218>\
**Category:** GNU Radio\
**Created:** [July 28, 2014, 5:25am UTC](https://www.ruby-forum.com/t/spectrum-record/231218 "2014-07-28T05:25:40Z")\
**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:** [July 28, 2014, 5:25am UTC](https://www.ruby-forum.com/t/spectrum-record/231218/1 "2014-07-28T05:25:40Z")

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Hi Marcus, list,  
Thanks for swift response.  
You are right about openBTS, but at the same time I am using really old  
system (12.04) havent formatted for years due to its required  
installation,  
which can turn into real time consuming tasks thats why dragging it as  
long  
as I can avoid above situation.  
Now Decimation, yes its seems right to me as well, but when I am trying  
to  
decode I am getting SCH errors (I am using channelizer.py given in GR  
example directory for this purpose) with following configuration  
channels= 10  
sample rate= clock rate/decimation  
pfb decimation= 4  
OSR= channels/pfb decimation= 2.5

but when I am recording single frequency with 156 decimation, it works  
just  
fine.  
partially I believe this question belongs to airprobe mailing list, but  
think there is very little or null development on it, thus thought to  
coin  
it here, a much active list.  
I want to make sure I am not doing anything wrong in spectrum recording  
and  
channelizing afterwards once it comes to airprobe, will give a head on  
Also if libusrp is the only bottelneck for me, I will change my system  
configuration and install GR-3.6 (which I think supports openBTS and UHD  
as  
well)  
at moment I am moving like headless chicken between GR and airprobe, not  
sure who is and what is going wrong, please spread some light here.  
Thankyou

---

<div class="post-metadata">

**Author:** ![gsmandvoip](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/e19adc/32.png) [@gsmandvoip](https://www.ruby-forum.com/u/gsmandvoip)\
**Post date:** [July 28, 2014, 10:28am UTC](https://www.ruby-forum.com/t/spectrum-record/231218/2 "2014-07-28T10:28:53Z")

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BTW, 12.04 is perfectly fine for GNU Radio dev.

M