Why no NR in Data modes

[Mike K2MK]

I was wondering why the NR feature is unavailable in data modes. During the
WPX using AFSK A on 80 meters it seems like it would have been beneficial to
have some noise reduction. (I use MixW).

Mike K2MK

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[Julian, G4ILO]

K2MK wrote

I was wondering why the NR feature is unavailable in data modes. During the
WPX using AFSK A on 80 meters it seems like it would have been beneficial to
have some noise reduction. (I use MixW).

The DSP demodulators that are used by programs like MixW to decode data modes aren't bothered by the noise at all. Or at least, the effect of the noise is less than it would be if NR was used, which will inevitably remove some useful information along with the noise.

Possibly the NR would be useful if someone was using the K3 audio output to feed an analog decoder. But nobody would do that, would they?

[David Woolley (E.L)]

K2MK wrote:
> I was wondering why the NR feature is unavailable in data modes.
> During the WPX using AFSK A on 80 meters it seems like it would have
> been beneficial to have some noise reduction. (I use MixW).

Because it would remove the signal.  One of the main functions is, I
believe, to act as an adaptive notch filter, which would mean that, most
likely, it would notch out the spacing tone on RTTY.  Also the most
optimal digital modes tend to be almost indistinguishable from random
noise to anything other than the matched demodulator.

Basically, NR reduces subjective noise for speech, but will play havoc
with digital modulation.


--
David Woolley
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Elecraft products and more general topics related ham radio"
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