Save data (newbie)

Hi all,

I went through the tutorial of GnuRadio, and got some basic idea of
it. I am using two FEX400 d’board on two different m’board, so one is
used to transmit, another is used to receive; and and are used. But I don’t think the signal is receiving at
receiver side. I want to save the output of the transmitter to a data
file, and also the receiver side, and see whether it has signal sending
and receiving. Can anyone tell me why doesn’t work, and
how to save signal to a .dat file?

BTW, I connect two USRP on one computer, it should work, right?

I really appreciate,