address@hidden:/usr/local/share/gnuradio/examples/digital# ./benchmark_tx.py -f 900000000 --tx-amplitude=0.36 -v --tx-gain=0.0 -r 40000 -m bpsk

linux; GNU C++ version 4.5.3 20110311 (prerelease); Boost_104500; UHD_003.003.000-e0a7b8a

Traceback (most recent call last):
  File "./benchmark_tx.py", line 148, in <module>
    main()
  File "./benchmark_tx.py", line 112, in main
    tb = my_top_block(mods[options.modulation], options)
  File "./benchmark_tx.py", line 49, in __init__
    options.antenna, options.verbose)
  File "/usr/local/share/gnuradio/examples/digital/uhd_interface.py", line 135, in __init__
    freq, gain, antenna)
  File "/usr/local/share/gnuradio/examples/digital/uhd_interface.py", line 51, in __init__
    num_channels=1)
  File "/usr/local/lib/python2.6/site-packages/gnuradio/uhd/__init__.py", line 84, in constructor_interceptor
    return old_constructor(*args, **kwargs)
  File "/usr/local/lib/python2.6/site-packages/gnuradio/uhd/uhd_swig.py", line 2003, in usrp_sink
    return _uhd_swig.usrp_sink(*args, **kwargs)
RuntimeError: Network is unreachable