USRP2 Transmitter

I have tried transmitting an analog signal from one USRP2 to another,
but
when I run usrp2_fft.py on the rx computer, there is no receive signal.
The
analog signal is supposed to be two tones at 350 and 440 HZ transmitted
at
2.6GHz. Can anyone help me figure out what I am doing wrong?