reading rfm69 packet transmission

[Chris Gorman]

Hello All,

I have two rfm69 boards [1] connected to two avrs and they are sending
messages to each other over the airway.  Once I got this working I
thought it would be fun to inspect the messages being sent with my
rtl_sdr.  I can confirm the message is being sent over serial on the
receiver.

I went searching on the internet for a way to decode the transmission
and found some scripts to use gnuradio to do packetdemod on rfm69
boards [2].  The problem with this setup is it requires me to modify
the code to the rfm69 [3] to prevent whitening.  My software to run
the avrs isn't the same as the author of the packetdemod's and I can't
apply his patch.  I have looked at the code to see if I am using
whitening, but as far as I can tell I am not.  Regardless when I run
the packetdemod script, I get 'Invalid packets" instead of my message.

In my inbox this morning I found an email with a reference to packet
communications with gnuradio [4] and am wondering if I should be using
this method to decode the transmission between the two rfm69's?  I
will try it out anyway as it seems interesting, but is this the
correct direction to analyze the transmission between two boards like
the rfm69s?

Thanks in advance,

Chris

[1] https://www.sparkfun.com/products/12775
[2] https://github.com/fermitron2048/packetdemod
[3] https://github.com/nayem-cosmic/RFM69-Library-AVR
[4] https://wiki.gnuradio.org/index.php?title=Packet_Communications