[Elecraft] K2 CW Filter Characteristics

[Bill Tippett]

         Doing a little research on the K2 and have a few questions about
the CW filters.  I've searched the list archives and also the K2 manual but
figure some of you may be able to answer answer my questions.

Page 109 of the current K2 manual states:

 >"A 5-pole variable-bandwidth crystal filter is used on CW (X7-X11). This
filter is optimized for use at low bandwidths (~200 to 500 Hz), but can be set
both narrower and wider as needed with only a small additional loss. The
shape factor and passband ripple content are optimized at around 300 Hz."

  I've seen varying reports of what the K2's actual bandwidths are (e.g. 
ARRL's Test Report).

 >ARRL Expanded Test report ( 
http://www2.arrl.org/members-only/prodrev/pdf/lab/k2.pdf )
1. The crystal filter option selected was 700 Hz nominal bandwidth. 
However, the actual bandwidth of the filter was
considerably narrower (about 350 Hz), making this option closer to the 
desired 500 Hz width than the 400 Hz option.

Questions:

1.  What is the actual 6 dB BW, combined 6/60 dB shape factor (X7-11
plus X5-6) and passband ripple for various "selected" bandwidths from
minimum (200 Hz?) to about 1 kHz?  What I'm looking for is actual data
from measurements (Spectragarm if it has 60 dB DR or spectrum analyzer)
similar to the following:

Selected BW   Actual BW  Shape Factor  Passband Ripple
      700            350         2.1:1           3 dB

2.  What is the minimum "selectable" BW  (Spec sheet says only "~200 Hz")
and what is its actual BW?

3.  Why aren't "selectable" and "actual" bandwidths closer?

                                         73,  Bill W4ZV