only a test with DFCW-Opera ;-). Just another idea to generate an Opera signal with an uninterrupted carrier, as a workaround for transmitters with flipflops. The upper frequency carries the desired
Ah 2FSK , Could call it Redundant Tone Transmitting sYstem or RTTY for short ; -) But , yes, Opera decoder is backwards compatible to FSK beacons , either shifting inside the decoder pass band or out