I'm using 2 USRP1s to send and receive a simple sine wave using UHD. The TX/RX frequencies are 2.45 GHz as I have RFX 2400 as daughterboards.
I use the UHD example tx_waveforms to transmit a sine wave of 10 kHz, sample rate 250ksps. I received the waveform at the other end using the UHD example rx_samples_to_file to dump the output to a binary file. I used a receiving sample rate of 250ksps. I used this file as a file source in a grc flowgraph, hooked up its output to the Oscope sink (after converting the interleaved short I,Q binary file to complex in the chain). I'm seeing a clear sine wave, but its frequency is 5kHz, rather than 10 kHz.