Hello,
A few issues in those flowgraphs:
-I am not sure what USRP model you are using, but your sampling rate does not sound correct. Your USRP probably don't support that sampling rate.
-Why are you multiplying the data by 5000 before putting it to the USRP sink?
-Your USRP probably don't support 100dB of TX gain. Also, increasing the TX/RX gain level do NOT always improve the data quality (especially when the transmitter and the receiver are located closely).
-Center freq for the USRP source and USRP sink are different.
-You are mixing DBPSK and DQPSK in your flowgraphs.
-PSK Demod block is just for a quick testing, and do not really work well if you start the receiver flowgraph before the transmitter. So, you should try executing the transmitter flowgraph before starting the receiver flowgraph.
Regards,
Kyeong Su Shin