Looking for VERY simple example

Hi discuss-gnuradio,

I have what is likely a very simple question that I am hoping someone
answer without too much trouble. Perhaps I just overwhelmed at the
flexibility of GNURadio or have forgotten all my signal processing class
topics, but I haven’t been able to find an example of how to make
perform what I assume is a very simple task.

I want to be able to monitor an unmodulated 1 Mbps data stream at a
frequency, basically just turning the waveform into binary digits, and
analyze the stream to look for a certain pattern that identifies the
beginning of a data packet which I can then capture and unpack into a
structure for further processing.

Is this something that can be done with existing GNURadio blocks and
Python code or will I need to write my own custom block?

Any pointers to examples would be greatly appreciated.