[Elecraft] Trying to get to grips with the KDSP2 Filter

[Ken Alexander]

Hi Ray,

I'm not an expert on the DSP, but my K2 has one and I'm happy with it.  
To answer your questions:

1.  The CW filters, like the SSB and RTTY filters are activated by using 
the AFIL button on the front panel.  nr = noise reduction  I think the 
DSP filter comes already configured, although I'm not positive about 
that because I didn't buile mine either.  Hopefully, some smarter person 
will jump in and help.  Regardless, you can cownload a copy of the KDSP2 
manual from the Manuals and Downloads section of the Elecraft website.  
It will tell you how to configure and use the filter.

2.  The settings shown are perfectly good.  The manual explains what 
everything means.  My interpretation is that the left hand number is the 
frequency where the low pass filter kicks in and the right hand number 
is the bandwidth...1 kHz for general uncrowded conditions and 200 Hz 
during contests when the band is packed with signals.

3.  The noise reduction works well on CW signals, although it softens 
them somewhat, which some people don't like.  But it does get rid of a 
lot of noise!  There are several "strengths" to which the noise 
reduction can be set.  I've always found the lowest setting to be the 
best but that's a personal preference.  Noise reduction isn't available 
with the RTTY filters because it degrades the signal too much and makes 
decoding difficult.

Definitely download yourself a copy of the manual!

Happy New Year,

Ken Alexander
VE3HLS


On 03/01/2012 6:47 AM, Ray G3XLG wrote:
> I am the 2nd owner of my K2 and have so far largely "ignored" the DSP filter
> but I thought I'd look into it further following my poor performance in a
> recent RTTY contest where some contacts were difficult but eventually OK and
> others were unable to decode my signals at all.
> So far I have found the DSP filter settings currently in the K2 are as
> follows:
> SSB
> S1. .00  2.9
> S2. .20  .2.5
> S3. .30  .1.9
> S4.  .30 .1.6
> Which I understand show that the denoiser is not currently activated, the
> notch is on and the other figures are the lower&  upper cutoff frequencies
> in kHz.
> CW
> CF1  nr
> CF2  nr
> CF3  nr
> CF4  nr
> So it appears my DSP is not active on CW?
> RTTY
> r1  LPA.SS
> r2 2.5  .1.0
> r3 2.2  .30
> r4 1.0  .20
> I think this shows the centre frequencies of 1 to 2.5kHz&  the width of 0.2
> to 1.0kHz with filters r2, r3&  r4?
>
> My questions are:
> - why would the CW filters not be active&  what does "nr" mean?
> - what are typical DSP settings for RTTY, and are the ones in use OK?
> - any other comments re these settings?
>
> Still learning about this rig!
> 73
> Ray, G3XLG
>
>
> -----
> Ray G3XLG
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/Trying-to-get-to-grips-with-the-KDSP2-Filter-tp7146478p7146478.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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