http://elecraft.85.s1.nabble.com/K2-power-on-frequency-problem-tp6756612p6759570.html
This is my problem. I have 120Hz drift. I have been unable to
correct it and I sent my K2 to you and others without results. Let
I come into the shack in the morning, it is about 65 degrees. I turn
on the rig. The display says 7000.004 Khz. I hit the band button and
shift to 10Mhz WWV. I hit the "zero beat" button and it gives me a
matching tone. I zero the main tuning knob, and it verifies that WWV
CQ. If I don't find one in about 1/2 hour I go back to 10Mhz
WWV. It now zeros at -3Hz ie. 9999.997 Khz.
Now I get lucky. I find a CQ, I crank up the power to 100 Watts and
I call him. I'm not fooling around, we do a real rag chew and we
talk for perhaps 30 minutes. As I notice him drifting, and my
beat with my QSO. He stops drifting when my dial reads 7043.993
KHz. Now the QSO ends and my K2 has stabilized. I return to 10MHz
>John,
>
>You are reporting a shift of 128 Hz in one case, and 117 Hz in another
>case. The difference between the two is close to 20 Hz which is the K2
>BFO DAC limit, so that is not surprising, particularly if the BFO
>voltage to the DAC is right on the "edge".
>
>Yet, I do not understand what approximately 120 Hz has to do with CW or
>CWr - unless you have the K2 sitting close to an AC transformer, sine
>120 Hz is twice the 60 Hz line frequency and the shift is coming from
>the VFO.
>
>You may have some inconsistency in addressing the EEPROM. If that is
>the case, it will be cured by a Master Reset - BUT record all your menu
>settings before doing the reset and restore them afterwards. The K2 A
>to B Instructions contain nice tables for recording the menu values, and
>I encourage you to download those instructions to record the menu
>parameters.
>
>I would suggest you use the N6KR method to set the 4 MHz reference - the
>precise setting may be slightly different than exactly 4 MHz, and the
>N6KR method erases any variables other than your ability to tune WWV (or
>any other "standard" station) with precision in SSB mode.
>For the full K2 Dial Calibration procedure, see the article dealing with
>that subject on my website www.w3fpr.com. If you only want to set the 4
>MHz reference using the N6KR method and then run CAL PLL and CAL FIL,
>you can refer to Wayne's document from the Elecraft reflector archives
>of 8/20/03.
>
>Remember, setting the 4 MHz Reference Oscillator by itself does nothing
>to the dial calibration, one must run CAL PLL and CAL FIL to set the new
>values (based on the new setting of the Reference) into EEPROM before
>any chance in tuning is made.
>
>73,
>Don W3FPR
>
>On 9/3/2011 9:24 AM, John Oppenheimer wrote:
> > I am a new K2 (#7212) user. I have been baffled by what I thought was my
> > inability to properly perform the frequency alignments. My last attempt
> > was to perform a factory reset and re-do PLL and BFO (Table 8-1 values)
> > calibrations.
> >
> > I believe that I have found the issue, sometimes it appears that the VFO
> > frequency offset look-up tables are not used and a toggle through two
> > "CW REV" changes are needed.
> >
> > Used a K3 CWT SPOT as a 4MHz monitor to adjust C22.
> >
> > Using a K3, CWT, SPOT and K2 in in TUNE (with dummy load) to measure the
> > K2's frequency. Test process is:
> >
> > Note: only the events in the below text were performed.
> >
> > Power off K2 with F set to 7026.00
> > Power on: K2 F=7026.00 K3 F = 7026.146
> > "CW REV" "CW REV", K3 F = 7026.018
> > Power off K2
> > Power on K2 F=7026.00, K3 F = 7026.025
> > Power off K2
> > Power on K2, Move K2 F to 7027.00, K3 F = 2027.028
> > Power off K2
> > Power on K2 F = 7027.00, K3 F = 2027.145
> > "CW REV" "CW REV", K3 F = 7027.000
> >
> > I was listening to the audio during the above process. There was a
> > notable change in the resulting pass-band audio when the "CW REV" "CW
> > REV" toggle was performed and the K2 frequency changed. Leading me to
> > believe that the VFO offset frequency was changed.
> >
> > Though I can't find a reproducible process, I have found events where
> > during a K2 power on session, sometimes a "CW REV" "CW REV" is needed to
> > acquire correct K2 frequency.
> >
> > Is this normal K2 operation, or do I have an issue with this K2?
> >
> > John, KN5L
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