This example will only receive 802.11b standard waveforms. I believe many routers do not transmit that beacon by default, you may have to edit the router setup to transmit this beacon. For this reason we are planning to remove this example in a future release.
This example is also designed to always receive data. Whether the data samples coming from the board to the host contain valid data or not is encoded into the sample stream. If you look in the subsystem "zynqRadioQPSKRxFPGAAD9361AD9364SL/QPSK Receiver/HDLRx/FPGA to Host" you will see that the valid signal is packed into one of the data samples. The host will receive a constant stream of data, but that doesn't necessarily mean that the data is good. Rest assured that the data path from your antenna, through the algorithm and back to MATLAB/Simulink should be good!