# B210 two-channel operation

**URL:** <https://www.ruby-forum.com/t/b210-two-channel-operation/233977>\
**Category:** GNU Radio\
**Created:** [January 27, 2015, 8:30pm UTC](https://www.ruby-forum.com/t/b210-two-channel-operation/233977 "2015-01-27T20:30:15Z")\
**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 27, 2015, 8:30pm UTC](https://www.ruby-forum.com/t/b210-two-channel-operation/233977/1 "2015-01-27T20:30:15Z")

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Hello,

OS: Ubuntu 14.01.1  
gnu-radio: 3.7.6  
Dell Optiplex 765

I am having trouble using the B210 USRP in two channel mode.  
Things work well when I use grc to configure the B210 with one channel,  
but when I try using two channels, I get the error shown below. This  
is quite similar to a problem I had earlier with a TVRX2, which was  
fixed with a “-M build.” I am still using the same build and the  
TVRX2 continues to work fine. Perhaps I am not configuring the B210  
properly? I attach the .grc and top\_block.py files.

Any suggestions would be most welcome.

Sincerely,  
Dan Marlow

Executing: “/home/marlow/gnuradio/B210/top\_block.py”

linux; GNU C++ version 4.8.2; Boost\_105400; UHD\_003.008.000-50-gb228b755

Using Volk machine: ssse3\_64\_orc  
libGL error: failed to load driver: swrast  
– Operating over USB 2.  
– 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’.  
Traceback (most recent call last):  
File “/home/marlow/gnuradio/B210/top\_block.py”, line 178, in   
tb = top\_block()  
File “/home/marlow/gnuradio/B210/top\_block.py”, line 99, in **init**  
self.uhd\_usrp\_source\_0.set\_samp\_rate(samp\_rate)  
File  
“/usr/local/lib/python2.7/dist-packages/gnuradio/uhd/uhd\_swig.py”, line  
2774, in set\_samp\_rate  
return \_uhd\_swig.usrp\_source\_sptr\_set\_samp\_rate(self, \*args,  
\*\*kwargs)  
RuntimeError: LookupError: IndexError: multi\_usrp: RX channel 1 out of  
range for configured RX frontends

---

<div class="post-metadata">

**Author:** ![danmcb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/13edae/32.png) [@danmcb](https://www.ruby-forum.com/u/danmcb)\
**Post date:** [January 27, 2015, 8:34pm UTC](https://www.ruby-forum.com/t/b210-two-channel-operation/233977/2 "2015-01-27T20:34:56Z")

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On 01/27/2015 02:29 PM, Daniel M. wrote:

> TVRX2, which was fixed with a “-M build.” I am still using the same
> 
> libGL error: failed to load driver: swrast  
> – Performing timer loopback test… pass  
> RuntimeError: LookupError: IndexError: multi\_usrp: RX channel 1 out of  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)  
> Your subdev spec should be:

A:A A:B