On Mon, 23 Mar 2009 15:28:51 -0700, "Joel Koltner"
wrote:

I realized awhile back that noise is the primary factor that limits how far
you can transmit a signal and still recovery it successfully. (Granted, these
days it's often phase noise in oscillators rather than the noise figures in
amplifiers that determines this, but still.)

Hi Joel,

This is an antiquated consideration limited to amplitude modulation,
the same specie as noise. I suppose there are noise products that
fall into the phase/frequency category that lay claim to "primary
factor," but that is a rather limited appeal.

Deep space communications proceeds many dB below the noise floor
enabled through technology that has become ubiquitous in cell phones -
Spread Spectrum. I have developed pulsed measurement applications for
which any single pulse has a poor S+N/N, but through repetition
improves S+N/N response with the square root increase of samples
taken.

73's
Richard Clark, KB7QHC