@profoundlynerdy Propagation is a function of wavelength, not of transmission mode; so propagation-wise, same. *But* CW needs only a few percent of the bandwidth of a narrow FM signal, so with good filters, you will be picking up a lot less noise around the frequency of interest. That alone is going to result in being able to communicate at distances where similarly powered FM would be untenable. Morse code is also decodable at a narrow margin above the noise floor; FM needs a strong S/N ratio.