It's an error in grc. The block 'Modulate vector' is not proper
evaluated. Just open and close the block 'Modulate vector' in the
property editor then you get the error message :
Value "digital.modulate_vector_bc(mod.to_basic_block(), data, taps)"
cannot be evaluated:
'NoneType' object has no at
I am trying to make my own version of packet_rx.grc. I copied the
flowgraph and began modifying it. I found that at some point I started
getting this error when I open the flowgraph:
ERROR:gnuradio.grc.core.FlowGraph:Failed to evaluate variable block
modulated_sync_word
Traceback (most recent
