[Elecraft] K3 SSB Noise Reduction

[Lyle Johnson]

> OK, I accept what you are all saying about the gain, I was just 
> postulating :)
> I agree it does drop off, but I didn't think that much.
> Anyone tried it with CONFIG:AF GAIN set LO? I haven't, just wondered.
> If there was a config control for an offset, it would need to be based 
> on the 4 'strenghts' I think, not on the Fx number, but the digit after 
> the -

The first value you see -- the Fx -- has to do with the aggressiveness 
of the filter.  The second value you see specifies the blend of 
processed and unprocessed audio.

Keep in mind always that the denoiser is not a denoiser; it is a signal 
enhancer.  It will act to suppress *everything* until it decides there 
is some sort of signal present, then act to pass that signal.  The more 
the signal appears to be a pure tone (like CW) the faster and more 
decisively the algorithm acts.  The less it looks like a signal (noisy 
SSB comes to mind) the slower and less decisively the algorithm acts.
This is why the audio level is low to begin with.

For CW with reasonable S/N, it usually quickly builds up to the same 
overall amplitude as without the NR.

For SSB with poor S/N, it builds up slowly and to a lesser overall 
amplitude.

Thus, observations that the signal amplitude sometimes or often appears 
reduced are correct.  The disagreements about how much it is reduced are 
also correct.

It depends on the NR settings, the S/N of the signal you are listening 
to at the moment, the type of signal, the IF and AF bandwidth...

FWIW, I usually have mine set to F1-1 or F1-2 for SSB operation. YMMV.

73,

Lyle KK7P