21 March 2015

FSK-CW (or FSK/Morse)

FSK-CW, also known as SFK/Morse, means Frequency Shift Keying CW and is a variant of QRSS (extreme slow speed CW, from Q-code QRS) that instead of activate/deactivate the carrier, the carrier is always activated as long as the transmission lasts. During pauses between dots, dashes or characters the frequency is shifted downwards. Whilst the upper trace shown on the screen contains the Morse information the lower trace is drawn during signal pauses. 
The advantage of this mode is its redundancy. If, for instance, a dash is falling into pieces caused by QRM there's still a chance to determine subsequently by checking the lower trace if the signal really had contained that dash or rather several dots. 

The copies in figures are from Russian Navy.

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