[Elecraft] K2: CW passband tuning

[Don Wilhelm]

Tom,

The K2 always uses the FL1 BFO for transmitting, so that must be set 
properly for transmit (do not shift that one - for SSB, visually center 
that passband between 300 and 2600 Hz on Spectrogram (assuming you have 
the 2.4 kHz SSB filter width).

I have found that SSB intelligibility degrades significantly if the low 
frequency corner of the passband is set higher than 300 Hz.  I typically 
align the SSB filters FL2 thru FL4 to progressively more narrow widths 
than the FL1 (OP1) filter.  Each filter 200 to 300 Hz more narrow than 
the previous one.  Set the low frequency corner of each filter at 300 Hz 
and try it.
By aligning the SSB filters this way, you can tap XFIL to reduce any 
QRM/QRN you hear at a high audio frequency and the desired signal will 
still be intelligible.  If you attempt to cut the low frequency end 
significantly, the signal quickly become unintelligible.

73,
Don W3FPR

Tom Z wrote:
> I am finally getting comfortable with the K2 in CW contests. One thing
> I want to do is set up my filters ( I have KDSP2), so I can shift the
> passband slightly to either side. I nkow I heard this discussed
> before. Does anyone have a good set of filter parameters that have
> given good performance in really crowded conditions?
>
> Can I assume that my transmit frequency will stay fixed as I shift the
> receiver passband? I think only the sidetone freq. will change.
>
> 73,
>
> Tom KG3V
>
>