[Discuss-gnuradio] Full Duplex and RFX900 USRP2

[Sharif Shaher]

Hello,

 

I have an application that requires me to continuously recieve a signal, while

continuously transmitting a delayed version of that recieved signal.  As a result

I need full duplex. I have a USRP2 and the rfx900 daughter board.  My plan

is to use the TX/RX port to transmit while using the RX2 port to recieve.  However,

I can not seem to get anything to listen/recieve on port RX2.  For example when

I run usrp2_fft.py and insert

 

self.subdev.select_rx_antenna('RX2).

 

this gives the error shown below.  By searching this forum I see where someone

has suggested that I rebuild the firmware by making these changes (for the rfx_900),

.base.atr_txval=0  ------> .base.atr_txval=MIX_EN | ANT_SW

.base.atr_rxval= MIX_EN --------> base.atr_rxval= MIX_EN | ANT_SW

 

However, will this a) work, that is allow me to use the RX2 port to recieve and b)

will it fix the problem shown below when I insert the call to self.subdev.select_rx_antenna('RX2).

Any help would be greatly appreciated.

 

Traceback (most recent call last):

  File "./usrp2_fft.py", line 275, in <module>

    main ()

  File "./usrp2_fft.py", line 271, in main

    app = stdgui2.stdapp(app_top_block, "USRP2 FFT", nstatus=1)

  File "/usr/local/lib/python2.5/site-packages/gnuradio/wxgui/stdgui2.py", line 36, in __init__

    wx.App.__init__ (self, redirect=False)

  File "/usr/lib/python2.5/site-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7836, in __init__

    self._BootstrapApp()

  File "/usr/lib/python2.5/site-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7433, in _BootstrapApp

    return _core_.PyApp__BootstrapApp(*args, **kwargs)

  File "/usr/local/lib/python2.5/site-packages/gnuradio/wxgui/stdgui2.py", line 39, in OnInit

    frame = stdframe (self.top_block_maker, self.title, self._nstatus)

  File "/usr/local/lib/python2.5/site-packages/gnuradio/wxgui/stdgui2.py", line 60, in __init__

    self.panel = stdpanel (self, self, top_block_maker)

  File "/usr/local/lib/python2.5/site-packages/gnuradio/wxgui/stdgui2.py", line 81, in __init__

    self.top_block = top_block_maker (frame, self, vbox, sys.argv)

  File "./usrp2_fft.py", line 112, in __init__

    self.subdev.select_rx_antenna('RX2')

  File "/usr/local/lib/python2.5/site-packages/gnuradio/gr/top_block.py", line 94, in __getattr__

    return getattr(self._tb, name)

AttributeError: 'gr_top_block_sptr' object has no attribute 'subdev'