[Elecraft] [K3] Noise on wsjt-x waterfall

Bill Frantz frantz at pwpconsult.com
Thu Nov 30 22:16:28 EST 2017


Jim, K9YC suggested some places to look that I hadn't thought 
of. When I turned off the "Flatten" option in the waterfall 
window, the noise bands went away. What I think is happening is 
that the algorithm in wsjt-x that flattens the response for the 
window sees the total lack of energy outside the K3's selected 
band and boosts the levels of the signals and noise near it as 
part of its compensation strategy.

73 Bill AE6JV

On 11/30/17 at 2:11 PM, frantz at pwpconsult.com (Bill Frantz) wrote:

>I have a K3 which has been upgraded to have the Elecraft internal USB sound card.
>
>I tried adjusting the DSP bandwidth when running FT8 to 
>eliminate a strong signal above the FT8 subband and noticed 
>that there was a strong noise bar on the water fall for about 
>400 Hz below the high cutoff. Further playing with the controls 
>showed a similar noise bar just above the low cutoff. Note that 
>these noise bars are in the requested pass band.
>
>Has anyone else observed this noise? Does anyone have an explanation?
>
>73 Bill AE6JV

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