[Elecraft] K3 SSB Contour Filter (reduce total bandwidth)

[Lyle Johnson]

>>  I am quite aware that the gurus at Elecraft 
>> are extremely busy and need evidence that firmware changes are 
>> beneficial. That is why I asked that those with the KRX3 should try my 
>> method and report their findings.
>> 	The K3 has a great CW receiver but SSB improvements seem to be on the 
>> back burner.
>>
> Tony, I verified that intelligibility is maintained with a null in the
> passband center as you suggested, and it's an interesting effect.  But I'm
> not convinced that this will bring an improvement in QRM immunity...

The NBVM people took this a step further.  Once the spectrum was 
notched, they shifted the upper frequency range down by the notch width, 
resulting in a narrower overall spectrum while maintaining intelligibility.

Ignoring the bandwidth for the moment, the question becomes, "Is the 
resulting voice signal acceptable under crowded band conditions?"

73,

Lyle KK7P