Secret to K2 calibration programming?

[WE0H]

OK, here the deal. My K2 S/N 6698 doesn't have the same freq offset on
all the bands. How can I program that so it is dead nuts on every band?
Here's the freq measurement spots and what the radio is showing as a
center freq using Spectrogram.

Signal freq then radio's displayed freq...
1.90000   1.90003
3.90000   3.90003
5.50000   5.50003
7.20000   7.20003
10.1000   10.1004
14.2000   14.2005
18.5000   18.5005
21.2000   21.2000
24.9000   24.9001
28.2000   28.2001


See how it is not the same offset across the bands? Something funny is
going on here...

Thanks for the help.

--
Mike
WE0H
K2 #6698
SKCC #5446

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[Don Wilhelm-4]

Mike,

First there is up to a +/- 20 Hz tolerance that can be attributed to the
K2 DAC, so "dead nuts on" may not actually be achievable, but you can
get close.  First question is - what are you using for a reference?  How
much do you trust its frequency accuracy?  That is one potential source
of error.

Secondly, you are reporting discrepancies up to 500 Hz, and that is more
than is to be expected after doing the K2 dial calibration.

I suggest you go to my website www.w3fpr.com and look at the article
dealing with K2 Dial Calibration.  Follow the 3 steps mentioned in that
article, and then re-check the calibration.  The 4 MHz reference
oscillator must be set before any other step.  Use the N6KR method when
setting the reference, and I highly recommend observing the WWV
transmitted tones with Spectrogram to determine the correct tuning of
WWV.  Accuracy in setting the reference is critical to the result -
allow your K2 to warm up for an hour or more before attempting to set
the 4 MHz reference.

73,
Don W3FPR

Mike-WE0H wrote:

> OK, here the deal. My K2 S/N 6698 doesn't have the same freq offset on
> all the bands. How can I program that so it is dead nuts on every band?
> Here's the freq measurement spots and what the radio is showing as a
> center freq using Spectrogram.
>
> Signal freq then radio's displayed freq...
> 1.90000   1.90003
> 3.90000   3.90003
> 5.50000   5.50003
> 7.20000   7.20003
> 10.1000   10.1004
> 14.2000   14.2005
> 18.5000   18.5005
> 21.2000   21.2000
> 24.9000   24.9001
> 28.2000   28.2001
>
>
> See how it is not the same offset across the bands? Something funny is
> going on here...
>
> Thanks for the help.
>
>  
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>
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[WE0H]

Copying this to the reflector in case someone else has seen the same
issue. This is K2 S/N 6698.

OK here is the run down on all bands:

Band         Displayed error

160m          .98      20hz low
75m            .99      10hz low
60m            .99      10hz low
40m            .99      10hz low
30m            .00      perfect
20m            .00      perfect
17m            .02      20hz high
15m            .09      90hz high
12m            .11      110hz high
10m            .11      110hz high

All bands were dialed to a even number and the last two digits are what
I listed above. Something is not right above 15mc.

Now I know the CAL PLL is done right and verified with my DDS & oven
oscillator showing the exact calibration as the radio now. Something is
not right somewhere. Hardware problem? I don't know. At least I have the
10mc calibration spot on.

Mike
WE0H
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