[Elecraft] DSP question

[Lyle Johnson]

Hello Vic!

> My question is:  does the NR work as well with narrow DSP filters as
> with wide?  Or does the same effect occur as with the crystal filters,
> limiting the effectiveness of the NR when the bandwidth is narrowed?

The nature of the noise reduction algorithm is that it is looking for
"coherence" in the signal.  Noise, passed through a sufficiently narrow
filter, sounds more and more like a signal.  So, you can expect that the
denoise will be less effective as the filter bandwidth is narrowed - but
then, the narrower bandwidth is taking care of much of the noise.

I think the real value of the denoiser in CW operation is when the IF/AF
bandpass is opened up so you can hear more stations not on your frequency,
like listening to an otherwise quiet band.  If the QRM gets bad, narrow
filters are probably your most effective weapons.

73,

Lyle KK7P