Re: [Discuss-gnuradio] RX channel 1 out of range for configured RX frontends

[Daniel Marlow]

On Nov 3, 2014, at 5:59 PM, Marcus D. Leech wrote:

On 11/03/2014 05:55 PM, Daniel Marlow wrote:

Hello,

    We are using a TVRX2 board with a N200 USRP.    Until recently, the system was working properly with two channels using the attached flowgraph.    For reasons that are unclear, it stopped working and is no longer capable of two channel operation (if we set the Num channels parameter to 1, the system works, but with only one channel).    So far as we can 
tell, nothing in the S/W changed.

 Version details and the  error message appears below.  Suggestions what has gone wrong would be most appreciated.

--Dan

There's a fix for this problem in the most recent "master" of GR, which doesn't appear in the "maint" branch.

It was a wee problem in gr-uhd that was introduced by wanting to be more "strict" about master-clock LOCK, and, well, that provoked
  other underlying problems.

What are you using the TVRX2 for, BTW.  I'll note that it has cannot-be-defeated hardware AGC, so it's of only limited utility for
  radio astronomy, which I think you're probably using it for.... :)

Hi Marcus,

   Thanks.      Does that mean we need a new install of GR?   The one we have is quite recent.  

Regarding the TVRX2, I did not know about the AGC issue.   We are using it for RA (pulsar searches).     Since we are doing synchronous detection, it's not clear to me that the AGC will be a fundamental problem, since we don't need quantitative power measurements.  We wanted two channels since we are using crossed Yagi's.     I don't see any alternatives from Ettus.

--Dan

H/W:  Dell Optiplex  Dual 2.4 GHz, 2 GB / USRP N200  with TVRX2 GPSDO boards.
OS: Ubuntu 14 
gnuradio:  3.7.6

Traceback (most recent call last):
  File "/home/marlow/gnuradio/TVRX2/top_block.py", line 177, in <module>
    tb = top_block()
  File "/home/marlow/gnuradio/TVRX2/top_block.py", line 94, in __init__
    channels=range(2),
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/uhd/__init__.py", line 122, in constructor_interceptor
    return old_constructor(*args)
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/uhd/uhd_swig.py", line 1753, in make
    return _uhd_swig.usrp_source_make(*args)
RuntimeError: LookupError: IndexError: multi_usrp: RX channel 1 out of range for configured RX frontends

http://www.hep.princeton.edu/~marlow/gnuradio/TVRX2.png

http://www.hep.princeton.edu/~marlow/gnuradio/TVRX2.grc

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-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

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