[Elecraft] K2-CW-Filter-Response: is that ok?

[Vic Rosenthal]

Karsten Eppert(DK4AS) wrote:

> I have set the wide CW-Filter (Fil1) to 1,5 and aligned the BFO to a 
> pitch of 700 Hz. I applied HF of constant frequency to the 
> receiver-input with a signal strength that generated S9+10 db max. and 
> plotted the S-meter versus variation of the VFO from high pitch to low 
> pitch in 100 hz-steps. So I could determine a filter-curve. What strikes 
> me is, that even at very low pitch-frequencies there is hardly 
> attenuation and even at zero beat the S-meter still shows approx. S3. 
> Turning the VFO "behind" zero-beat lets the S-meter decrease but it 
> takes another 300 Hz until S0 is reached. The tone of the "wrong" 
> sideband remains audible at even higher frequencies.

There's probably nothing wrong with your filter.  If you wish to have a wide CW 
filter setting, you should locate the BFO during the CAL FIL adjustment so that 
the filter passband is higher with respect to zero beat.  If you use Spectrogram 
-- see <http://www.n0ss.net/index.html#Spectrogram> -- you can see this graphically.

With correct adjustment, you should not hear any signal on the 'wrong' side of 
zero beat.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco