I've just completed soldering the K2, and have WWV at 10Mhz tuned in. The display shows it at +380 hz high. According to the manual, on page 60, the K2 can be calibrated using WWV. Unfortunately I do not see the procedure to do this. Is it published ? Could I have a link to a a procedure on how to do
this ? Thank you in advance. Douglas Todd ------------------------------ Yeah, it's sort of buried on the Elecraft Web site under "Notes on Adjusting C22 to Put the K2 on Frequency". I'll send you a PDF directly. For any lurkers who are also curious, it's there on the web site somewhere under "Construction Notes" I think. The title says it all. It's not about "calibrating the dial", it's all about putting the K2's internal clock on exactly 4.000 MHz (or as close as you can) so that when you run CAL PLL and CAL FIL, the K2 in CAL FCTR mode accurately measures the frequencies produced. Then the firmware can put the rig more accurately on frequency when you set the dial. The absolute accuracy is limited by a couple of factors. One is the stability of the oscillators themselves. While crystal oscillators are used for the BFO and the PLL reference oscillator, they still can drift slightly. Indeed, both of those oscillators are designed to be adjusted in frequency. The BFO frequency is adjusted to properly position the filter bandpass during CAL FIL. The PLL Reference oscillator (the "local oscillator") is actually tuned over a range to provide the nice smooth K2 tuning within each 'step' in the PLL. Whenever you make an oscillator that is supposed to change frequency, it will naturally try to change frequency on its own. That is, it will drift, at least somewhat. Finally the logic circuits limit how accurate the dial calibration can be even if there was no drift at all in the oscillators. When you tune in a frequency, the firmware generates a certain digital value for the BFO and PLL Reference oscillators that puts them on the right frequencies (it's these values that are measured and stored during CAL PLL and CAL FIL). Logic circuits change these digital values into analog voltages that actually control the oscillator frequencies. There's a finite limit to the accuracy with which the conversion from the digital value to the analog voltage can take place. The residual error in the logic affects the dial accuracy. Because of all those factors, the dial accuracy will typically be somewhere within 30 Hz or so of the actual frequency, but may be off as much as 30 Hz or so. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
