[Elecraft] K2: Help, I messed up the dial calibration!!!

[Steve Kallal]

Don,

I got back it in the ball park. I read the W5YR instructions on your web 
site, about the 5th harmonic of 4 MHz of 20 MHz. Fortunately WWV on 20 
MHz is still coming in on the west coast, but fading out. After all this 
work, I am back where I was except about 40 Hz low for zero beat on 10 
MHz, instead of the former 30 Hz, before exercise in futility hi hi.

Yes I am using CW mode, but not in the way you think. My CW Pitch is set 
of 450 Hz. I turn on the CW spot, adjust the volume, listen for zero 
beat against the WWV carrier. CW Reverse is usually within 10 Hz using 
this method.

I don't like zero beating with LSB/USB  because of the guess work of 
determining the 0 Hz beat with such a wide frequency range of 
sub-audible tones.

One thing I discovered is that C22 can't be adjust while listening for 
zero beat with a known reference like WWV. I suspect after each tweak of 
C22, CAL PLL and CAL FIL should be rerun. Is this correct?

Also CAL FIL seems to change zero beat anyway. You say on you web site 
that 30 Hz is a reasonable ball park figure. I'd prefer to be closer. 
WWV 10 MHz is zero beat at 99999.97 MHz LSB & 99999.95 MHz USB. That is 
a little much for me. I am not sure if C22 needs re-tweaking or maybe a 
slight change in CAL FIL for LSB/USB OP1.

I don't have a frequency counter here. But I do have another rig with a 
2nd receiver. It picks up the 4 MHz clock (and its 5th harmonic) easily 
with a pickup loop. What do you think the  easiest way is for me get it 
closer with these tools?

At least I am in the ball park again!

73,

Steve N6VL
K2/100 #2289


Don Wilhelm wrote:
> Steve,
>
> Your steps are correct.
>
> It sounds like you are off by the amount of your sidetone pitch.
> Were you receiving WWV in LSB or USB mode?  If you used CW mode, that 
> would explain the difference.
>
> Are you quite certain that you tuned WWV accurately?   Do not 'set the 
> dial at 10,000.00', but instead, ignore the dial and tune until WWV is 
> received correctly.  I use Spectrogram for that with markers 
> (pointers) set at 500 and 600 Hz for that.   When correctly tuned, you 
> will see the tones alternate each minute from 500 to 600 Hz (yes, I 
> know there are no-tone minutes, and one minute shortly after the hour 
> is 440 Hz, but mostly they alternated between 500 and 600 Hz.).
>
> When done correctly (mostly tuning WWV accurately), you results will 
> be within 20 Hz of WWV.  One cannot expect much better than that due 
> to the DAC resolution used in the K2.  I do this most every day, and 
> it has become 'old hat' to me - use Spectrogram to verify the correct 
> tuning - ignore the K2 dial display until the last verification step.
>
> 73,
> Don W3FPR