When you say "machine" modes, are you meaning CW decoded by software or by
the brain (be it aurally or visually) ? There is a profound difference...
73, Alberto I2PHD
This is all-important. Extremely weak stations require considerable
additional work by the 'computer between the ears' to decipher
what is signal and what is noise on the screen - just like aural
Morse, but visual. This accounts for several extra dB of gain, and
however slow you send the Morse, this advantage is still available.
It would take a very sophisticated computer to be as good.
There are, of course, advantages in having modes with little or no
manual intervention. Suppose, for instance, it were possible to
monitor for a transatlantic beacon and raise an alarm when a
callsign (or some pattern) was recognised by the computer. This
may be where BPSK comes into its own as being superior other
purely machine-read modes.
Mike, G3XDV (IO91VT)
http://www.dennison.demon.co.uk/activity.htm
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