On 05/04/2019 17:58, Frederic Beaulieu wrote:
Is FT8 a transmission of an audio 8-FSK signal that is then used to
modulated the amplitude of a carrier (USB) or a “pure” 8-FSK rf signal?
Hi Fred,
they are both correct. The term "pure" above is not relevant. The FT8
audio that is fed to an SSB transmitter is constant amplitude therefore
the modulated RF is also constant amplitude. Even though the transmitter
is set to an AM mode (SSB), the signal is not amplitude modulated.
The emission designation is F1B as opposed to J3E where voice is used to
modulate an SSB transmitter.
For a single carrier FSK signal the average power is equal to the PEP,
but that does not allow you to run 2,250 W RF, PEP must only be used to
measure SSB voice modulation. You should apply rule 10.2(a) or
10.2(b)(ii), i.e. the maximum power is either 1,000 W DC input or 750 W
average output power measured in an impedance-matched load.
73
Bill
G4WJS.
_______________________________________________
wsjt-devel mailing list
wsjt-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/wsjt-devel
