Problem with RFX900 daughterboard

Hi,everyone!
I’m trying to transmit square wave from one RFX900 at frequency
915MHz,and I use the spectrum analyser to receive the signal.That’s
right to work.But after several days,I want to transmit square wave from
TX/RX port and receive it from RX2 port with two antenna.First I execute
a terminal to run transmit program,then I execute the other terminal to
run usrp_oscope.py receive the square wave.Two program run at the same
time.At first I can see the square wave at scope sink,but in a moment
the signal degrade a lot and became more and more strange.At the last
test,I transmit the square wave from TX/RX and receive from spectrum
analyser,but I can’t see the signal anymore.I doubt RFX900 daughterboard
is breakdown.I add my square wave code.Could everybody tell me what’s
wrong about my experiment or my code?

Thanks for help
Henry

class filesource (stdgui.gui_flow_graph):
def init(self,frame,panel,vbox,argv):
stdgui.gui_flow_graph.init (self,frame,panel,vbox,argv)

    src=howto.mysource(1000000,gr.GR_SIN_WAVE,40000,1)
    amp=gr.multiply_const_cc(8000)
    aa=gr.binary_slicer_fb()
    bb=gr.char_to_float()
    cc=gr.float_to_complex()
    self.connect(src,aa,bb,cc,amp)

    inter=128000000/1000000
    freq=915e6
    sink=usrp.sink_c(0,inter)
    subdev=(0,0)
    m = usrp.determine_tx_mux_value(sink,subdev)
    sink.set_mux(m)
    subdev1=usrp.selected_subdev(sink,subdev)
    print "Using TX d'board %s" % (subdev1.side_and_name(),)
    r=usrp.tune(sink,0,subdev1,freq)
    subdev1.set_enable(True)

    self.connect(amp,sink)

    if 0:
       scope = scopesink.scope_sink_c(self, panel, 

sample_rate=1000000,
frame_decim=1,
v_scale=500,
t_scale=0.000025)
self.connect(amp,scope)
vbox.Add (scope.win, 1, wx.EXPAND)

if name == ‘main’:
app = stdgui.stdapp (filesource, “”)
app.MainLoop ()


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First, the RFX900 is not intended to transmit to itself.

Why don’t you try just sending a sine wave first? The whole slicer,
char to floar, float to complex thing does not do what you think it
does. Or, you could try sending the output of your system to a file
instead of a usrp. Then you can see what it wrong with it.

Matt