On 04/07/17 18:37, Jim Brown wrote: > The split mode in WSJT-X is simply a crutch for those who don't know (or > don't care) how to set audio levels so that distortion is not produced > in the audio chain. Sorry, but that's nonsense.
With a strong signal, just 1% distortion will produce audio harmonics that are only 40-ish dB down on the fundamental. That's plenty to cause QRM. With these modes it's possible to have work a station that's 60 dB down on another just a few Hz away. WSJT-X, being based on 16-bit digital audio, has an inherently high dynamic range. The split mode exists (a) to enable people to work over a wider range of frequencies than a single SSB channel, and (b) to ensure that the Tx audio frequency is always at least 1500 Hz, ensuring that *low-level* harmonics get filtered out. Even with a clean TX and audio levels set just so, it's well worth having that extra filtering in place. 73, Richard G4DYA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
