Bernie,
My first suspicion is in the BFO area. Unfortunately, some of those
connections are under the L33 BFO inductor.
It is possible that you have a bad BFO crystal. But think about it a
bit before doing anything to decide if it is the BFO or the PLL/VFO
causing the problem.
Since you have a significant shift in frequency, if you use the most
narrow CW filter, has the audio pitch the same as you had set for the
filter center, or is the pitch substantially different. You can observe
the frequency at the center of the filter passband with Spectrogram.
What I am getting at is that if the BFO is changing frequency, the audio
pitch when the signal is tuned to the center of the narrow CW filter
will be different than you chosen center frequency.
OTOH, if the audio pitch stays the same, but you can retune (to that
same pitch) with the RIT or by moving the VFO, then the problem is in
the PLL/VFO area.
73,
Don W3FPR
On 4/11/2015 3:06 PM, Bernie and Cheryl wrote:
Dear Frank and Don:
My K2 serial number is 6922.
With regard to Don's suggestion about improper filter setup, I have
redone the filters several times, always following the instructions on
Don's website. Always, I come out of that with the filters working
properly, and only after a long time, I find I have to adjust the RIT
in order to get the signal within the filter's bandpass.
Since my serial number is above 3000, then that means that I have the
new BFO inductor and the Temperature
Compensated PLL Don refers to. Thus, I wonder if it is a bad solder
connection.
Where would I look for the bad solder connection? And also, is that
the possible cause of my periodic need to readjust the filter settings?
Thanks and 73 de Bernie, KF0QS
At 10:34 AM 4/11/2015, Frank Krozel wrote:
Bernie,
What is your serial number?
Frank KG9H
> On Apr 11, 2015, at 11:13 AM, Bernie KF0QS <ham...@ix.netcom.com>
wrote:
>
> Dear OM's and YL's:
>
> Twice, I've had people tell me my K2 (which I've had on the air for
over 3
> years) drifts a bit in frequency. Both times have occurred during
long
> QSO's so it appears to be a slight drift.
>
> This phenomenon may also explain something else that happens.
Whenever I
> set up the filter settings, they work well for a while. After a
while, the
> sweet spot (i.e., the point at which the heard signal is in the
middle of
> the filter bandpass) seems to migrate eventually to about 1khz below
> wherever I set it (at least that's where I have to move the RIT to
hear the
> signal when I switch in the filters).
>
> Is there a common fix for both these problems, or am I experiencing
two
> different things. Any help you can give would be appreciated.
>
> 73 de Bernie, KF0QS
>
>
>
> --
> View this message in context:
http://elecraft.365791.n2.nabble.com/K2-drift-tp7601236.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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