On 2/21/2020 10:27 PM, Ria, N2RJ wrote:
FT8 doesn’t have a carrier. It’s SSB suppressed carrier. It’s FSK and its signal shifts during transmission. The word “may” and not “required” is used. So the part about where 60m FT8 must operate dead center is not really backed by anything.Ria,
Your logic for "not dead center" flawed. Otherwise I'm with you. An FT8 signal is NOT an SSB signal, it is an FT8 signal. WSJT-X is written so that an SSB transmitter can generate any of a dozen or so different signals, including FT8, in much the same way that other software uses an SSB transmitter to RTTY, PSK31, Olivias, etc.
Put another way, every FT8 signal occupies that 50Hz bandwidth somewhere above the nominal SSB carrier, and there can be hundreds of them. Narrow down a receiver in CW mode and tune past them -- each is a different signal, using digital modulation.
73, Jim K9YC