[Elecraft] [K2} Xtal filter calibration numbers

[Don Wilhelm]

Brian,

For the SSB option - yes, that number can be used to set the BFO 
frequency to the value listed in the KSB2 manual and will produce a 
workable filter setting for SSB OP1 filter (with a 2.4 kHz width).

There is no similar chart for the basic K2.  Add to that the fact that 
the varactor characteristics have changed recently (same type number, 
different characteristics, but usable), and the wide filter widths 
(those above 1.00) can be much wider than indicated by the K2 display 
and make the use of Spectrogram or other audio spectrum display 
application be used to properly set the width of these wide filters (the 
SSB filters and CW FL1).  This situation is present in K2s sold over the 
last couple years - for older K2s the displayed width and the actual 
filter widths track nicely.  Fortunately, when the filter width is at 
the more normal CW widths, the tracking is still quite good, so the 
default settings work OK.  To obtain optimum settings, it is still 
necessary to either have an ear that will detect pitch quite well or use 
Spectrogram or other to set the BFOs.

In short, do not believe the filter widths greater than 1.00 in K2s 
having serial numbers above 6000, but use a tool to measure the actual 
filter width.  I have seen cases where a width setting of 2.00 produced 
a filter that was in excess of 3 kHz wide.

73,
Don W3FPR

Brian Denley wrote:
> The K2 manual and the SSB option manual urge builders to save the xtal 
> calibration numbers written on the envelops they came in with the statement 
> that those numbers will be useful later for filter calibration.  But I don't 
> see where these numbers ever get used.  Has anyone else actually used those 
> numbers?
> Brian
> http://home.comcast.net/~b.denley/index.html 
>
>