Fw: C22

[Gordon Gibson-2]

Hi Elecrafter's

When I built my K2 #2746 4 years back now I set C22 near enough using an
external frequency counter, then last year I added the SSB board, I noted
that I was about 200 Hz high as I do not work near band edges I left it at
that, but recently decided I would get it a bit nearer however I now find
that moving C22 does absolutely nothing, the trimmer cant be open or short
circuit as I am still pretty near correct on CW.

a local pal who has recently built a K2 has found the same problem when he
built his K2 he calibrated C22 okay but now finds that moving C22 does
nothing I have studied the circuit and I just can not figure out why this
should be so

I am quite happy to leave it as it is but if anyone has any idea why it
would be appreciated

73 de Gordon G3ZFZ

Remember that a lone amateur built the Ark.
 A large group of professionals built the Titanic.


[hidden email]

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[Vic K2VCO]

Gordon Gibson wrote:

> a local pal who has recently built a K2 has found the same problem when
> he built his K2 he calibrated C22 okay but now finds that moving C22
> does nothing I have studied the circuit and I just can not figure out
> why this should be so

The exact frequency of the 4 MHz oscillator is only relevant during the
calibration procedure.  If you change the setting, you *must* run CAL
PLL followed by CAL FIL (and you must change the BFO settings in CAL FIL
even if you return them to their previous values) before you will see a
change.

For details, see:
<http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf>
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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[Don Wilhelm-3]

Gordon,

During operation of the K2, the reference oscillator is not used except as
the oscillator for the microprocessor - so there will be no observed effect
from changing the C22 setting.

During the calibration steps (for an accurate CAL FCTR reading, and before
running CAL PLL or CAL FIL), the reference oscillator accuracy is important,
and should be set properly before any of these operations.

73,
Don W3FPR

> -----Original Message-----
>
> When I built my K2 #2746 4 years back now I set C22 near enough using an
> external frequency counter, then last year I added the SSB board, I noted
> that I was about 200 Hz high as I do not work near band edges I
> left it at
> that, but recently decided I would get it a bit nearer however I now find
> that moving C22 does absolutely nothing, the trimmer cant be open
> or short
> circuit as I am still pretty near correct on CW.
>
> a local pal who has recently built a K2 has found the same
> problem when he
> built his K2 he calibrated C22 okay but now finds that moving C22 does
> nothing I have studied the circuit and I just can not figure out why this
> should be so
>
> I am quite happy to leave it as it is but if anyone has any idea why it
> would be appreciated
>
>

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