[Elecraft] K3S Shift Setting for WSJTX

[Richard Lamont]

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