[Elecraft] K2 working on 40M

[Don Wilhelm]

Garry,

You don't need WWV to do the "N6KR" method - you can use any reference 
signal of known frequency and accuracy.  Subtract the BFO frequency from 
the VFO frequency and that should be the frequency of your reference - 
if it is not, then adjust C22 until that condition is true..  With WWV 
(or any other signal on a xxx0.00 frequency), the math is easy and one 
needs only to match the 3 low order digits in the K2 display.
Note - do not attempt to use 15 meters and above - the VFO and BFO are 
additive on those bands.

73,
Don W3FPR

2rGarry wrote:
> Thank you Don.   I think the most confusing part of all was, I was
> looking for various width settings for the ssb filters.  Eventually I
> came to realize that I had to use the other filters for reduced
> bandwidth for ssb.  After that dawned on me it was relatively easy.
> Or perhaps I still have not got it correct.  Still can't get the
> display on frequency.  I guess I need a decent freq counter.  Can't
> seem to manage with wwv.
>
> cheerio and 73.
>
> Garry
>
> On Thu, Feb 11, 2010 at 8:52 PM, Don Wilhelm-4 [via Elecraft]
> <ml-node+4559453-248936129 at n2.nabble.com> wrote:
>   
>> Garry and all - at least those who are building new K2s.
>>
>> Yes, the filter setup is a bit "tricky", especially when using filter
>> widths wider than 1.00 kHz.  The reason is in the varactors that have
>> shipped with the more recent K2 kits.  What that means is that a filter
>> width that is indicates as 2.00 kHz wide on the K2 may actually be 2.5
>> kHz wide (this is not exact, it all depends on the varactors).  The
>> result of this is that the LSB filter settings listed in the manual will
>> be about right, but the USB settings will be way off.  In other words,
>> the manual settings will give you a workable filter for the lower
>> sideband response, but will not work for the upper sideband (USB, RTTYr,
>> and CWr) settings. (NOTE: the OP1 filter width is not affected by the
>> varactors - there are no varactors on the KSB2 board).
>>
>> The only cure I know is to use Spectrogram or another audio spectrum
>> analyzer to measure the actual width of the filter (in LSB or CW - not
>> CWr -  or RTTY - not RTTYr).  When you use LSB, CW or RTTY, you should
>> be on the lower sideband, and you can change the width without much
>> movement of the lower end of the passband frequency.  After getting the
>> filer width as you like it, then refine the low frequency end of the
>> lower sideband filter (by changing the BFO setting) and then set the USB
>> BFOs to properly place the sideband.
>>
>> If you want specifics on how to set the filters, look at part 3 of the
>> article on K2 Dial Calibration at my website www.w3fpr.com (while you
>> are there, you may just want to go through the entire K2 Dial
>> Calibration procedure which includes adusting the filters.
>> I have not yet updated the webpage information to include how to handle
>> this "varactor problem", but since you can see the passband width on the
>> Spectrogram display, it should be obvious.  Just adjust the width of the
>> filter until the actual width is what you want, and use the K2 display
>> only as a relative indicator.
>>
>> 73,
>> Don W3FPR
>>     
>