[Elecraft] K3: Peculiar BW behavior?

[pd0psb]

Hi Walter,

A few things to look at:
In CW mode check how you've configured your roofing flters.
Could it be you switch to the 0.4 roofer at BW 0.2 ? >> CONFIG: FLx BW
Could it be the 0.4 roofer needs some more filter gain ? >> CONFIG: FLx GN

The "click" you hear at 0.1 is caused by the FIR-IIR filter switch-over.
Under 0.1 BW K3 switches over to Infinite Impulse Response to prevent
ringing.
NB: This switch-in of the IIR filter also bypasses the RX EQ.

So if you have RX EQ attenuating the CW freq ranges, you'll notice a gain-up
when narrowing under 0.1 BW. You can check this setting RX EQ flat.
Note that EQ will also be flat for all other modes then.
It's also possible to disable IIR switch over CONFIG: FLx BW>tap 7>IIR
on/off

I think you'll be able to solve by some reconfiguring.
The fact that you notice a difference on some bands will probably be caused
by a varying noisefloor throughout different bands.

73'
Paul
PD0PSB









Walter V. Gilles wrote:
> 
> Greetings,
>  
> I just came across what seems to be a rather peculiar operational quirk in
> my K3/100 while reducing the BW on CW.  I have 13, 2.8, 1.8 and 0.4
> roofing, running current firmware release suite.
>  
> On 20M CW for example, as I reduced the DSP BW down, and as I hit 0.20 the
> signal dropped significantly; at 0.15 it completely cut out; at 0.10 it
> popped in again at a normal volume but shifted enough in freq such that it
> took a goodly RIT input to find signal pitch again, but stayed there at
> 0.05.  Going back up in BW, it just reversed the process, going out at
> 0.15 and coming back in at 0.20 weak and shifted back in freq, then back
> to normal on up in BW.  This behavior seems mostly to show up on 20M, and
> fairly repeatable.  Occassioannly it will show up on other bands, but not
> as severe.
>  
> Also, on all bands, I hear a distinct click as the BW hits 0.10 going
> down, then another click as it hits 0.15 on the way up.  No clicking
> sounds anywhere else on BW changes (i.e. no clicks as the roofing filters
> switch in/out). Clicks can be heard in the K3 speaker, and headphones. 
> This clicking is repeatable on all bands.
>  
> The clicking is mildly annoying but new, and the BW behavior begs some
> words of wisdom if anybody has some ideas.  I have not reloaded the
> firmware yet, as that would be my next step to see if something got
> corrupted.  Note that this peculiar behavior was not present after I
> loaded the latest firmware - that went without a hitch as usual.
>  
> Soooo.....anybody have any ideas?  Thanks.  73
>  
> Walter   WB2IDK
> 
> 
>       
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