[Elecraft] K2 SSB Receive issue

[Don Wilhelm]

  I am going to make 2 assumptions - correct me if they are wrong.
1) You do not have the KSB2 installed with its fixed 2.4 kHz width 
filter, and you are attempting to use the variable IF filter at wide widths.
2) Your K2 has a serial number somewhere near 6800.

If those conditions are true, the 1SV149 varactors in your kit have a 
greater capacitance range than with the older varactors.
What that means is that your wide filters (above about 1.00 kHz) are 
much wider than indicated on the K2 display.  On one K2 I recently 
aligned a filter indicated as 1.70 was actually 2.4 kHz wide.  That is 
the most variation I have observed in many K2s that I have aligned, more 
typically an indicated filter width of 1.90 would be about 2.4 kHz wide.

What that means is that the BFO frequencies listed in the manual will be 
about correct for the LSB filters, but are nowhere near correct for USB.

The only way I know to correct this situation is to use Spectrogram to 
measure the actual filter width.  Set the BFO for LSB about correct 
first, then reduce the width of the filter to whatever width you would 
like - I use 2.4 kHz for FL1, 2.2 for FL2, 2.0 for FL3 and 1.8 for FL4.  
Those are the Spectrogram measured widths, not the K2 indicated widths.

After setting the filter widths, then trim up the LSB BFOs to place the 
upper "corner" of the left passband slope close to 300 Hz and then 
switch to USB and adjust the BFO so the upper passband corner is 
positioned also at 300 Hz.

You can find some information about using Spectrogram on Tom Hammond's 
website www.n0ss.net and also in part 3 of the K2 Dial Calibration 
article on my website www.w3fpr.com.

73,
Don W3FPR





On 1/15/2011 1:36 PM, KA1YMX wrote:
> I recently finished aligning my K2 with the spectrogram software and with the
> procedures from Elecraft. I am able to receive SSB on all bands except on
> 21m and 12m. The SSB signal is very distorted and sounds like the filter is
> not wide enough to receive the SSB signal.  I completed all of the
> alignments in the manual without any issues. I know I must have missed
> something small but cannot figure it out. Before I start to adjust anything
> on the K2, does anyone have any suggestions?