I have some digital recordings of some received over-the-air CW broadcasts of known plain-text (W1AW code practice) at known WPM code speeds, but in moderate to heavy RF noise and fading.
Can I describe a S/N ratio for the Morse Code in these recordings? If so, how would I calculate this S/N ratio? What bandwidths should I use for the signal and for the noise? Should I use recordings with or without the radio receivers narrow-band CW filter enabled?
If possible, I would like to use these S/N numbers to try and plot the decoding error rates versus the S/N ratios for various "demodulators" (including both software decoders, as well as humans at different experience levels).