http://elecraft.85.s1.nabble.com/K2-power-on-frequency-problem-tp6756612p6759807.html
is only 70 Hz. I am downstairs with my laptop and my memory is
you have given my this advice before. I owe you an apology! Please
>TR,
>
>What are you measuring the drift with? The K2 dial shows only 2
>decimal digits, so you can only read 7000.00 and not 7000.004 on the display.
>
>Drifting from 10000.004 to 9999.997 is only 7 Hz drift, and well
>within the K2 specifications.
>If you really mean 70 Hz drift (and you have inserted an extra zero
>after the decimal), then please provide that correction. Even 70 Hz
>is within the cold start spec for the K2.
>
>In addition, you are starting from a cold start - the K2
>specification is for less than 100 Hz from a cold start, so if your
>cold start drift is actually 70 Hz, it is well within spec.
>After warmup, the spec drift should be less than 30 Hz. to be within
>spec. Most are more stable than that. The 1/4 watt resistor on the
>Thermistor board can be altered to tighten this drift spec, but it
>takes some experimentation. I would not recommend trying to alter
>the resistor to reduce the cold start drift because that could
>result in the normal operating drift to be worse.
>
>Please let your K2 warm up for at least 5 minutes and re-check the
>drift with respect to WWV (choose the interval that you want to use
>for the test, and do at least 3 samples over time and average them).
>
>It would seem that the original poster in this thread had a problem
>different than drift.
>
>73,
>Don W3FPR
>
>On 9/4/2011 9:24 PM, wreese wrote:
>>Don,
>>
>>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
>>me give you an example.
>>
>>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
>>reads out at 10000.004 Khz
>>
>>Now, I do nothing.
>>
>>I go back to 7000.004 Khz and I tune around the band looking for a
>>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.
>>
>>I adjust the zero on 40 meters to read 6999.997 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
>>experience tells me that it isn't him drifting, it's me, I use the
>>tone zero beat and I adjust the main tuning knob to maintain zero
>>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
>>WWV and my dial reads 9999.993 KHz.
>>
>>Thanks,
>>
>>K6GC, TR
>>K2/100 S/N 838
>>________________
>>
>>At 05:07 PM 9/4/2011 -0400, Don Wilhelm wrote:
>>>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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