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Calibrating the Elecraft K3 reference oscillator with WWV

February 14, 2008

As already mentioned I have just finished building my K3. After construction there are a few settings to be adjusted, one stage being to calibrate the reference oscillator. Besides using a frequency counter (which I do not have) the suggested method is to zero beat with a signal of a known frequency, such as WWV. Now, I know how to zero beat and used that method with my K2, however I wondered if there was an alternative and more accurate method. A quick search of the internet came up with this posting from an archive of the Elecraft reflector, by Don Wilhelm, W3FPR.

The method is to use the tones in in WWV schedule to make the calibration. WWV has a regular format to its transmissions which can be seen here. Within a 2 minute cycle there is a 600 Hz and 500 Hz tone. It was these tones that I used to calibrate my reference oscillator. As I use Linux I used the baudline application for the spectral analysis. Baudline is an excellent tool, which is not open source but is free to use. Tuning to 5.0 MHz for WWV (5.0 MHz was a better signal than 10.0 MHz) I fed the audio into the computer and baudline. I adjusted the calibration setting (read your K3 Manual on how to do this) and soon had the 500 Hz and 600 Hz tones lined up. See the screenshots below by clicking on the thumbnails.

500 Hz tone 500 Hz tone from WWV

600 Hz tone 600 Hz tone from WWV

1000 Hz tone 1000 Hz tone from WWV

The calibration is easy and as Don suggests it is probably a very accurate method of alignment.

Thanks to Don, W3FPR for this tip on the calibration.

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2 Comments leave one →
  1. May 8, 2008 8:11 am

    You can use soundcard and frequency analyser on your computer to calibrate

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