I'm trying to send packet data from between two USRPs wirelessly using the slightly modified uhd_packet_tx/rx examples (attached). It appears that whenever the packet_rx block "finds" a correlation the entire flow graph hangs. I say "find" because in order to get any output from the correlation estimator block within packet_rx I have to set the threshold very low, so I'm not very confident that it's finding what it needs. I've tried playing around with the different encodings and header formats that are part of the example, but it doesn't seem to change anything.
First question: what could be causing the rx flowgraph to hang? I know some of the downstream blocks in the packet_rx hier block use the tags the correlation estimator outputs.
Second question: what are some things I can try to improve the detection in the first place?