Posted by
Scott Ellington-2 on
Apr 06, 2011; 3:15pm
URL: http://elecraft.85.s1.nabble.com/Elecraft-K3-Frequency-Calibration-using-Sidetone-tp6243828p6251009.html
My procedure is only a slight modification of Method 2 in the manual. The AGC will keep the audio level nearly constant under all but the worst conditions.
1. Select fine VFO resolution (1 Hz).
2. Select CW mode, fast AGC, and set bandwidth to 500 Hz. (You don't have to have a CW xtal filter.)
3. If using WWV, do the calibration only when the carrier is unmodulated. If you try it when there are audio tones, you may end up tuning to one of the sidebands.
4. Using CWT, tune to the calibration signal. This will get you very close to zero beat.
5. Locate CONFIG:REF CAL.
6. Tap SPOT to enable the sidetone, and adjust its level to be about the same as that of the signal. You should hear the "beat", a fluctuation in volume. If necessary, adjust the sidetone level for the strongest beat. (If you can't hear it when adjusting the sidetone level, shift the VFO a few Hz.) Tune the VFO for the slowest possible fluctuation, probably less than 1 per second. If you have trouble hearing the fluctuations, try feeding the audio to an analog voltmeter or oscilloscope.
7. Note the VFO display frequency. If it isn't within about 100 Hz of the calibration signal, adjust the REF CAL frequency in small increments, always retuning the VFO for zero beat as above, until the VFO display reads with 100 Hz of the calibration frequency. Once you get within about 100 Hz, set the VFO for exactly the calibration frequency, and adjust REF CAL for zero beat as above. (You may be close enough initially.)
8. Using the K3 utility, save the configuration. (Or record the REF CAL value.)
9. Cancel SPOT and exit the menu.
73,
Scott K9MA
On Apr 6, 2011, at 9:33 AM, Wes Stewart wrote:
> Or you can try this that I wrote exactly two years ago.
>
>
http://elecraft.365791.n2.nabble.com/Ref-Osc-Cal-Method-4-tc2595451.html>
> Wes N7WS
>
> --- On Wed, 4/6/11, Pete Smith <
[hidden email]> wrote:
>
>> From: Pete Smith <
[hidden email]>
>> Subject: Re: [Elecraft] [Elecraft K3] Frequency Calibration using Sidetone
>> To:
[hidden email]
>> Date: Wednesday, April 6, 2011, 4:47 AM
>> If you don't have perfect pitch, you
>> can use a technique I recently
>> described on the Reverse Beacon Network blog, substituting
>> Spectran for
>> a good ear, which I don't have. See
>> <
http://reversebeacon.blogspot.com/2010/12/frequency-calibration-and-rbn.html>
>>
>> for the full story.
>>
>> 73, Pete N4ZR
>>
>> The World Contest Station Database, updated daily at
>> www.conteststations.com
>> The Reverse Beacon Network at
http://reversebeacon.net, blog at
>> reversebeacon.blogspot.com,
>> spots at telnet.reversebeacon.net, port 7000
>>
>>
>>
>> On 4/5/2011 5:08 PM, David Robertson wrote:
>>> On usb mode I tune the K3 to the reference standard
>> you are using ( Any AM station such as WWV or any station of
>> a known frequency). I set the readout to the exact known
>> frequency of that station. I note the pitch of the sound I
>> hear from the station (the tone from WWV or CHU works best)
>> . Next I switch to LSB and note the pitch of the sound. If
>> they are identical then the K3 is calibrated. If the pitch
>> changes then you have to configure the master oscillator's
>> frequency so the pitch between USB and LSB match. I
>> relies the above method requires a good ability to note
>> slight changes in pitch. Some of us do not posses that
>> ability and must use a different method. For those that do,
>> this method works.
>> ______________________________________________________________
>>
> ______________________________________________________________
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http://www.qsl.net/donate.htmlScott Ellington
Space Science and Engineering Center
University of Wisconsin-Madison
[hidden email]
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